Tag Archives: 5G NR

5G NR Cyclic Prefix (CP) Design

15 Dec

Cyclic prefix (CP) refers to the prefixing of a symbol, with a repetition of the end In OFDM wireless systems. The receiver is typically configured to discard the cyclic prefix samples A CP  can be used to counter the effects of multipath propagation. The basics of CP is available in following post.

Multipath Signal Transmission

Radio channel between the base station and UE introduces delay spread in the time domain. This delay spread is generated by the transmitted signal reaching the receiver from multiple paths which have different distances environment, terrain, and clutter result in different delays.

Delay spread of the received signal pulse caused by multi-path is the difference between the maximum transmission latency in largest path and the minimum transmission latency in shorted path. The latency varies with the varies with the environment, terrain, and clutter, and does not have an absolute mapping relationship with the cell radius. This multi path delay spread can cause following:

  • Inter-Symbol Interference (ISI), which severely affects the transmission quality of digital signals
  • Inter-Channel Interference (ICI), the orthogonality of the subcarriers in the OFDM system is damaged, which affects the demodulation on the receive side

How Cyclic Prefix reducing ISI and ICI

  • Guard Period: To avoid Inter Symbol Interference a guard period can be inserted between OFDM symbols in the form of Cyclic Prefix. This guard period provides a time window for the delay spread components belonging to the previous symbol to arrive before the start of the next symbol. The guard period could be a period of discontinuous transmission or could be a transmission of anything else. The length (Tg) of the guard period is generally greater than the maximum delay over the radio channel
  • Cyclic Prefix: CP can be inserted in the guard interval to reduce ICI. Replicating a sampling point following each OFDM symbol to the front of the OFDM symbol. This ensures that the number of waveform periods included in a latency copy of the OFDM symbol is an integer in an FFT period, which guarantees sub carrier orthogonality. Copying the end of the payload and transmitting as the cyclic prefix ensures that there is a ‘circular’ convolution between the transmitted signal and the channel  response. This allows the receiver to apply a simple multiplication to capture the energy from all delayed components. If a ‘circular’ convolution was not completed then the receiver would experience ICI when completing the frequency domain multiplication

Key Factors to Determining CP Length

  • Multi path Delay: The multiple and CP length is directly proportional. The larger the multipath delay, requires longer Cyclic Prefix
  • Length of OFDM Symbol: Given the same OFDM symbol length, a longer CP can be  a large system overhead, so to control over overhead the length of CP shall be selected as appropriate.

CP Design in 5G NR

The basic desing of CP in NR is similar to LTE and same overhead as that in LTE. CP design ensure that it aligned symbols between different SCS values and the reference numerology (15 kHz). For example, µ=15 khz a single slot have about 7 symbols resides in 0.5 mili seconds including the CPs for each symbols and µ=30 khz a single slot have about 14 symbols including CPs for each symbols within same 0.5 milli sec. So here the length of CP is adapted based on subcarrier spacing (fsc).

Properties of CP in 5G NR

  • 3GPP has specified two types of cCPs, Normal Cyclic Prefix (NCP) and Extended Cyclic Prefix (ECP).
  • The NCP is specified for all subcarrier spacings
  • ECP is currently only specified for the 60 kHz subcarricr spacing.
  • If normal CP (NCP) is used, the CP of the first symbol present every 0.5 ms is longer than that of other symbols
  • Cyclic prefix durations decrease as the subcarrier spacing increases

CP Length for Different Subcarriers

The CP length for different sub-carrier can be calculated using following formula.

and CP time duration can be using following formula.

is numerology, l is the symbol index here and   is a constant  to relate NR basic time unit and LTE basic time unit and can be represented by following equation.

Ts is LTE basic time unit and  T is NR basic time unit. The details for timing can be read from following post.

Below is the summary of Cyclic Prefix duration based on above formula. Each numerology has 2 long symbols per 1 ms sub frame. These longer symbols are generated by increasing the duration of the normal cyclic prefix, to ensure that each numerology has an integer number of symbols within each 0.5 ms time window, while also ensuring that as many symbol boundaries as possible coincide, e.g. every symbol boundary belonging to the 15 kHz subcarrier spacing coincides with every second symbol boundary belonging to the 30 kHz subcarrier spacing.

Calculating CP Overhead

The CP overhead is a percentage ratio of CP time duration and Symbol time duration, for example 15KHz the NR symbol duration is 66.67 μs and CP duration is 5.2 µs. Then overhead can be calculated 5.2/66.67 = 7.8 % . Here the long symbol shall have more overhead as CP where as other symbols shall have less overhead. below table provides a summary of overhead for Normal CP for different sub carrier spacing.

Calculating Multi path support of each CP

The CP duration defines how much multiple distance is can support without affecting the Inter symbol interference (ISI) and Inter Carrier Interference (ICI). The distance be calculated using a simple Time, distance formula. For example, let’s take 15 KHz having CP for long symbol as 5.2 µs. The radio signal travel with velocity of light which is C= 3.0 x 108 m/s, then distance can be calculated as  velocity x time = (3.0 x 108 ) x (5.2 x 10-6 ) = 1560 meter. Similarly,  it calculated for other CPs and sub carrier spacing and summary is available in below table.

Source: http://www.techplayon.com/5g-nr-cyclic-prefix-cp-design/
15 12 19

Channel Coding NR

25 Aug

In 5G NR two type of coding chosen by 3GPP.

  • LDPC : Low density parity check
  • Polar code 

Why LDPC and Polar code chosen for 5G Network

Although many coding schemes with capacity achieving performance at large block lengths are available, many of those do not show consistent good performance in a wide range of block lengths and code rates as the eMBB scenario demands. But turbo, LDPC and polar codes show promising BLER performance in a wide range of coding rates and code lengths; hence, are being considered for 5G physical layer. Due to the low error probability performance within a 1dB fraction from the the Shannon limit, turbo codes are being used in a variety of applications, such as deep space communications, 3G/4G mobile communication in Universal Mobile  Telecommunications System (UMTS) and LTE standards and Digital Video Broadcasting (DVB). Although it is being used in 3G and 4G, it may not satisfy the performance requirements of eMBB for all the code rates and block lengths as the implementation complexity is too high for higher data rates.

Invention of LDPC

LDPC codes were originally invented and published in 1962.

(5G) new radio (NR) holds promise in fulfilling new communication requirements that enable ubiquitous, low-latency, high-speed, and high-reliability connections among mobile devices. Compared to fourth-generation (4G) long-term evolution (LTE), new error-correcting codes have been introduced in 5G NR for both data and control channels. In this article, the specific low-density parity-check (LDPC) codes and polar codes adopted by the 5G NR standard are described.

Turbo codes, prevalent in most modern cellular devices, are set to be replaced by LDPC codes as the code for forward error correction, NR is a pair of new error-correcting channel codes adopted, respectively, for data channels and control channels. Specifically, LDPC codes replaced turbo codes for data channels, and polar codes replaced tail-biting convolution codes (TBCCs) for control channels.This transition was ushered in mainly because of the high throughput demands for 5G New Radio (NR). The new channel coding solution also needs to support incremental-redundancy hybrid ARQ, and a wide range of block lengths and coding rates, with stringent performance guarantees and minimal description complexity. The purpose of each key component in these codes and the associated operations are explained. The performance and implementation advantages of these new codes are compared with those of 4G LTE.

Why LDPC ?

  • Compared to turbo code decoders, the computations for LDPC codes decompose into a larger number of smaller independent atomic units; hence, greater parallelism can be more effectively achieved in hardware.
  • LDPC codes have already been adopted into other wireless standards including IEEE 802.11, digital video broadcast (DVB), and Advanced Television System Committee (ATSC).
  • The broad requirements of 5G NR demand some innovation in the LDPC design. The need to support IR-hybrid automatic repeat request (HARQ) as well as a wide range of block sizes and code rates demands an adjustable design.
  • LDPC codes can offer higher coding gains than turbo codes and have lower error floors.
  • LDPC codes can simultaneously be computationally more efficient than turbo codes, that is, require fewer operations to achieve the same target block error rate (BLER) at a given energy per symbol (signal-to noise ratio, SNR)
  • Consequently, the throughput of the LDPC decoder increases as the code rate increases.
  • LDPC code shows inferior performance for short block lengths (< 400 bits) and at low code rates (< 1/3) [ which is typical scenario for URLLC and mMTC use cases. In case of TBCC codes, no further improvements have been observed towards 5G new use cases.

 

 The main advantages of 5G NR LDPC codes compared  to turbo codes used in 4G LTE 

 

  •         1.Better area throughput efficiency (e.g., measured in Gb/s/mm2) and substantially                 higher achievable peak throughput.
  •         2. reduced decoding complexity and improved decoding latency (especially when                     operating at high code rates) due to higher degree of parallelization.
  •        3. improved performance, with error floors around or below the block error rate                       (BLER) 10¯5 for all code sizes and code rates.

These advantages make NR LDPC codes suitable for the very high throughputs and ultra-reliable low-latencycommunication targeted with 5G, where the targeted peak data rate is 20 Gb/s for downlink and 10 Gb/s for uplink.

 

Structure of LDPC

 

Structure of NR LDPC Codes

 

The NR LDPC coding chain contain

  • code block segmentation,
  • cyclic-redundancy-check (CRC)
  • LDPC encoding
  • Rate matching
  • systematic-bit-priority interleaving

code block segmentation allows very large transport blocks to be split into multiple smaller-sized code blocks that can be efficiently processed by the LDPC encoder/decoder. The CRC bits are then attached for error detection purposes. Combined with the built-in error detection of the LDPC codes through the parity-check (PC) equations, very low probability of undetected errors can be achieved. The rectangular interleaver with number of rows equal to the quadrature amplitude modulation (QAM) order improves performance by making systematic bits more reliable than parity bits for the initial transmission of the code blocks.

NR LDPC codes use a quasi-cyclic structure, where the parity-check matrix (PCM) is defined by a smaller base matrix.Each entry of the base matrix represents either a Z # Z zero matrix or a shifted Z # Z identity matrix, where a cyclic shift (given by a shift coefficient) to the right of each row is applied.

The LDPC codes chosen for the data channel in 5G NR are quasi-cyclic and have a rate-compatible structure that facilitates their use in hybrid automatic-repetition-request (HARQ) protocols

General structure of the base matrix used in the quasi-cyclic LDPC codes selected for the data channel in NR.

To cover the large range of information payloads and rates that need to be supported in 5G NR,
two different base matrices are specified.

Each white square represents a zero in the base matrix and each nonwhite square represents a one.

The first two columns in gray correspond to punctured systematic bits that are actually not transmitted.

The blue (dark gray in print version) part constitutes the kernel of the base matrix, and it defines a high-rate code.

The dual-diagonal structure of the parity subsection of the kernel enables efficient encoding. Transmission at lower code rates is achieved by adding additional parity bits,

The base matrix #1, which is optimized for high rates and long block lengths, supports LDPC codes of a nominal rate between 1/3 and 8/9. This matrix is of dimension 46 × 68 and has 22 systematic columns. Together with a lift factor of 384, this yields a maximum information payload of k = 8448 bits (including CRC).

The base matrix #2 is optimized for shorter block lengths and smaller rates. It enables transmissions at a nominal rate between 1/5 and 2/3, it is of dimension 42 × 52, and it has 10 systematic columns.
This implies that the maximum information payload is k = 3840.

 

Polar Code 

Polar codes, introduced by Erdal Arikan in 2009 , are the first class of linear block codes that provably achieve the capacity of memoryless symmetric  (Shannon) capacity of a binary input discrete memoryless channel using a low-complexity decoder, particularly, a successive cancellation (SC) decoder. The main idea of polar coding  is to transform a pair of identical binary-input channels into two distinct channels of different qualities: one better and one worse than the original binary-input channel.

Polar code is a class of linear block codes based on the concept of Channel polarization. Explicit code construction and simple decoding schemes with modest complexity and memory requirements renders polar code appealing for many 5G NR applications.

Polar codes with effortless methods of puncturing (variable code rate) and code shortening (variable code length) can achieve high throughput and BER performance better.

At first, in October 2016 a Chinese firm Huawei used Polar codes as channel coding method in 5G field trials and achieved downlink speed of 27Gbps.

In November 2016, 3GPP standardized polar code as dominant coding for control channel functions in 5G eMBB scenario in RAN 86 and 87 meetings.

Turbo code is no more in the race due to presence of error floor which make it unsuitable for reliable communication.High complexity iterative decoding algorithms result in low throughput and high latency. Also, the poor performance at low code rates for shorter block lengths make turbo code unfit for 5G NR.

Polar Code is considered as promising contender for the 5G URLLC and mMTC use cases,It offers excellent performance with variety in code rates and code lengths through simple puncturing and code shortening mechanisms respectively

Polar codes can support 99.999% reliability which is mandatory for  the ultra-high reliability requirements of 5G applications.

Use of simple encoding and low complexity SC-based decoding algorithms, lowers terminal power consumption in polar codes (20 times lower than turbo code for same complexity).

Polar code has lower SNR requirements than the other codes for equivalent error rate and hence, provides higher coding gain and increased spectral efficiency.

Framework of Polar Code in 5G Trial System

The following figure is shown for the framework of encoding and decoding using Polar code. At the transmitter, it will use Polar code as channel coding scheme. Same as in Turbo coding module, function blocks such as segmentation of Transmission Block (TB) into multiple Code Blocks (CBs), rate matching (RM) etc. are also introduced when using Polar code at the transmitter. At the receiver side, correspondingly, de-RM is firstly implemented, followed by decoding CB blocks and concatenating CB blocks into one TB block. Different from Turbo decoding, Polar decoding uses a specific decoding scheme, SCL to decode each CB block. For the encoding and decoding framework of Turbo.

  NR polar coding chain

 

Source: https://cafetele.com/channel-coding-in-5g-new-radio/

5G mobile networks: A cheat sheet

17 Aug

As LTE networks become increasingly saturated, mobile network operators are planning for the 5G future. Here is what business professionals and mobile users need to know about 5G networks.

What is 5G?

5G refers to the fifth generation of mobile phone networks. Since the introduction of the first standardized mobile phone network in 1982, succeeding standards have been adopted and deployed approximately every nine years. GSM, the 2nd generation wireless network, was first deployed in 1992, while a variety of competing 3G standards began deployment in 2001. The 4G LTE wireless technology standard was deployed by service providers in 2010. Now, technology companies and mobile network operators are actively deploying 5G cellular networks around the world for new mobile devices. These 5G deployments accompany transitional LTE technologies such as LTE Advanced and LTE Advanced Pro, which are used by network operators to provide faster speeds on mobile devices.

Principally, 5G refers to “5G NR (New Radio),” which is the standard adopted by 3GPP, an international cooperative responsible for the development of the 3G UMTS and 4G LTE standards. Other 5G technologies do exist. Verizon’s 5G TF network operates on 28 and 39 GHz frequencies, and is used only for fixed wireless broadband services, not in smartphones. Verizon’s 5G TF deployments were halted in December 2018, and will be transitioned to 5G NR in the future. Additionally, 5G SIG was used by KT for a demonstration deployment during the 2018 Winter Olympics in Pyeongchang.

5G NR allows for networks to operate on a wide variety of frequencies, including the frequencies vacated by decommissioning previous wireless communications networks. The 2G DCS frequency bands, the 3G E-GSM and PCS frequency bands, and the digital dividend of spectrum vacated by the transition to digital TV broadcasts are some of the bands available for use in 5G NR.

5G standards divide frequencies into two groups: FR1 (450 MHz – 6 GHz) and FR2 (24 GHz – 52 GHz). Most early deployments will be in the FR1 space. Research is ongoing into using FR2 frequencies, which are also known as extremely high frequency (EHF) or millimeter wave (mmWave) frequencies. Discussions of the suitability of millimeter wave frequencies have been published in IEEE journals as far back as 2013.

Millimeter wave frequencies allow for faster data speeds, though they do come with disadvantages. Because of the short distance of communication, millimeter wave networks have a much shorter range; for densely-populated areas, this requires deploying more base stations (conversely, this makes it well suited to densely-populated places such as arenas and stadiums). While this would be advantageous in certain use cases, it would be a poor fit for use in rural areas. Additionally, millimeter wave communication can be susceptible to atmospheric interference. Effects such as rain fade make it problematic for outdoor use, though even nearby foliage can disrupt a signal.

Tests of early 5G mmWave networks by sister site CNET surfaced a number of performance problems, with the Moto Z3Samsung Galaxy S10 5G, and LG V50 depleting their battery faster than on 4G networks. In the case of the Moto Z3—which uses a pogo-pin connected Moto Mod add-on to deliver 5G—four hours of testing completely drained the battery in the attachment; the use of sub-6 GHz 5G networks is expected to lessen this effect. Likewise, increased efficiency in Qualcomm’s upcoming Snapdragon X55 modem will alleviate some performance issues.

It is vital to remember that 5G is not an incremental or backward-compatible update to existing mobile communications standards. It does not overlap with 4G standards like LTE or WiMAX, and it cannot be delivered to existing phones, tablets, or wireless modems by means of tower upgrades or software updates, despite AT&T’s attempts to brand LTE Advanced as “5G E.”While upgrades to existing LTE infrastructure are worthwhile and welcome advances, these are ultimately transitional 4G technologies and do not provide the full range of benefits of 5G NR.

For an overview of when 5G smartphones are being released, as well as the benefits and drawbacks of 5G smartphones, check out TechRepublic’s cheat sheet about 5G smartphones.

What constitutes 5G technology?

For mobile network operators, the 3GPP has identified three aspects for which 5G should provide meaningful advantages over existing wireless mobile networks. These three heterogenous service types will coexist on the same infrastructure using network slicing, allowing network operators to create multiple virtual networks with differing performance profiles for differing service needs.

eMBB (Enhanced Mobile Broadband)

Initial deployments of 5G NR focused on eMBB, which provides greater bandwidth, enabling improved download and upload speeds, as well as moderately lower latency compared to 4G LTE. eMBB will be instrumental in enabling rich media applications such as mobile AR and VR, 4K and 360° video streaming, and edge computing.

URLLC (Ultra Reliable Low-Latency Communications)

URLLC is targeted toward extremely latency sensitive or mission-critical use cases, such as factory automation, robot-enabled remote surgery, and driverless cars. According to a white paper (PDF link) by Mehdi Bennis, Mérouane Debbah, and H. Vincent Poor of the IEEE, URLLC should target 1ms latency and block error rate (BLER) of 10−9 to 10−5, although attaining this “represents one of the major challenges facing 5G networks,” as it “introduces a plethora of challenges in terms of system design.”

Technologies that enable URLLC are still being standardized; these will be published in 3GPP Release 16, scheduled for mid-2020.

mMTC (Massive Machine Type Communications)

mMTC is a narrowband access type for sensing, metering, and monitoring use cases. Some mMTC standards that leverage LTE networks were developed as part of 3GPP Release 13, including eMTC (Enhanced Machine-Type Communication) and NB-IoT (Narrowband IoT). These standards will be used in conjunction with 5G networks, and extended to support the demands of URLLC use cases on 5G networks and frequencies in the future.

The ways in which 5G technologies will be commercialized are still being debated and planned among mobile network operators and communications hardware vendors. As different groups have differing priorities, interests, and biases, including spectrum license purchases made with the intent of deploying 5G networks, the advantages of 5G will vary between different geographical markets and between consumer and enterprise market segments. While many different attributes are under discussion, 5G technology may consist of the following (the attributes are listed in no particular order).

Proactive content caching

Particularly for millimeter wave 5G networks, which require deploying more base stations compared to LTE and previous communications standards, those base stations in turn require connections to wired backhauls to transmit data across the network. By providing a cache at the base station, access delays can be minimized, and backhaul load can be reduced. This has the added benefit of reducing end-to-end delay. As 4K video streaming services—and smartphones with 4K screens—become more widespread, this caching capability will be important to improve quality of service.

Multiple-hop networks and device-to-device communication

In LTE networks, cellular repeaters and femtocells bridge gaps in areas where signal strength from traditional base stations is inadequate to serve the needs of customers. These can be in semi-rural areas where population density complicates serving customers from one base station, as well as in urban areas where architectural design obstructs signal strength. Using multiple-hop networks in 5G extends the cooperative relay concept by leveraging device-to-device communication to increase signal strength and availability.

Seamless vertical handover

Although proposals for 5G position it as the “one global standard” for mobile communications, allowing devices to seamlessly switch to a Wi-Fi connection, or fall back to LTE networks without delay, dropped calls, or other interruptions, is a priority for 5G.

Who does 5G benefit?

Remote workers / off-site job locations

One of the major focuses of 5G is the ability to use wireless networks to supplant traditional wireline connections by increasing data bandwidth available to devices and minimizing latency. For telecommuters, this greatly increases flexibility in work locations, allowing for cost-effective communication with your office, without being tied to a desk in a home office with a wireline connection.

For situations that involve frequently changing off-site job locations, such as location movie shoots or construction sites, lower technical requirements for 5G deployment allow for easily set up a 5G connection to which existing devices can connect to a 5G router via Wi-Fi. For scenes of live breaking news, 5G technologies can be used to supplant the traditional satellite truck used to transmit audio and video back to the newsroom. Spectrum formerly allocated to high-speed microwave satellite links has been repurposed for 5G NR communication.

Internet of Things (IoT) devices

One priority for the design of 5G networks is to lower barriers to network connectivity for IoT devices. While some IoT devices (e.g., smartwatches) have LTE capabilities, the practical limitations of battery sizes that can be included in wearable devices and the comparatively high power requirements of LTE limit the usefulness of mobile network connectivity in these situations. Proposals for 5G networks focusing on reducing power requirements, and the use of lower-power frequencies such as 600 MHz, will make connecting IoT devices more feasible.

Smart cities, office buildings, arenas, and stadiums

The same properties that make 5G technologies a good fit for IoT devices can also be used to improve the quality of service for situations in which large numbers of connected devices make extensive use of the mobile network in densely populated areas. These benefits can be realized easily in situations with variable traffic—for instance, arenas and stadiums are generally only populated during sporting events, music concerts, and other conventions. Large office towers, such as the 54-story Mori Tower in Tokyo’s Roppongi Hills district, are where thousands of employees work during the week. Additionally, densely populated city centers can benefit from the ability of 5G networks to provide service to more devices in physically smaller spaces.

When and where are 5G rollouts happening?

Early technical demonstrations

The first high-profile 5G rollout was at the 2018 Winter Olympic Games in Pyeongchang, South Korea. KT (a major mobile network operator) Samsung, and Intel collaborated to deliver gigabit-speed wireless broadband, and low-latency live streaming video content. During the games, 100 cameras were positioned inside the Olympic Ice Arena, which transmitted the video to edge servers, then to KT’s data center to be processed into “time-sliced views of the athletes in motion,” and then transmitted back to 5G-connected tablets for viewing. This demonstration used prototype 5G SIG equipment, which is distinct from the standardized 5G NR hardware and networks being commercialized worldwide.

Similarly, Intel and NTT Docomo have announced a partnership to demonstrate 5G technology at the 2020 Tokyo Olympic Games. The companies will use 5G networks for 360-degree, 8K-video streaming, drones with HD cameras, and smart city applications, including “pervasive facial recognition, useful for everything from stadium access to threat reduction.”

Other 5G tests and rollouts have occurred worldwide. Ericsson and Intel deployed a 5G connection to connect Tallink cruise ships to the Port of Tallinn in Estonia. Huawei and Intel demonstrated 5G interoperability tests at Mobile World Congress 2018. In China, ZTE conducted tests in which the company achieved speeds in excess of 19 Gbps on a 3.5 GHz base station. Additionally, in tests of high-frequency communications, ZTE exceeded 13 Gbps using a 26 GHz base station, and a latency of 0.416 ms in a third test for uRLLC.

Where is 5G available in the US?

Verizon Wireless deployed mmWave-powered 5G, marketed as “Ultra Wideband (UWB),” in Chicago, IL and Minneapolis, MN on April 3, 2019; in Denver, CO on June 27, 2019; in Providence, RI on July 1, 2019; in St. Paul, MN on July 18, 2019; and in Atlanta, GA, Detroit, MI, Indianapolis, IN, and Washington, DC on July 31, 2019.

Future deployments of Verizon’s 5G services have been announced for Boston, MA, Charlotte, NC, Cincinnati, Cleveland, and Columbus, OH, Dallas, TX, Des Moines, IA, Houston, TX, Little Rock, AR, Memphis, TN, Phoenix, AZ, Providence, RI, San Diego, CA, and Salt Lake City, UT, as well as Kansas City, by the end of 2019.

Verizon Wireless started deployments of its 5G fixed wireless internet service on October 1, 2018 in Los Angeles and Sacramento, CA, Houston, TX, and Indianapolis, IN. Verizon’s initial 5G network deployments use its proprietary 5G TF hardware, though the company plans to transition these networks to 5G NR in the future. Verizon’s 5G TF network is only used for home internet service, not in smartphones.

AT&T has active 5G deployments in Atlanta, GA, Austin, Dallas, Houston, San Antonio, and Waco, TX, Charlotte, NC, Indianapolis, IN, Jacksonville and Orlando, FL, Las Vegas, NV, Los Angeles, San Diego, San Francisco, and San Jose, CA, Louisville, KY, Nashville, TN, New Orleans, LA, New York City, NY, Oklahoma City, OK, and Raleigh, NC. Deployments have also been announced for Chicago, IL, Cleveland, OH, and Minneapolis, MN.

AT&T has deployed LTE Advanced nationwide; the company is marketing LTE Advanced as a “5G Evolution” network, though LTE-Advanced is not a 5G technology. AT&T has a history of mislabeling network technologies; the company previously advertised the transitional HSDPA network as 4G, though this is commonly considered to be an “enhanced 3G” or “3.5G” standard.

Sprint started deployments of 5G on May 30, 2019 in the Dallas / Ft. Worth and Houston, TX, Kansas City / Overland Park, KS, and Atlanta, GA metro areas. Sprint’s 5G networks run on 2.5 GHz, providing more widespread coverage throughout a region than is possible on line-of-sight mmWave connections, though with a modest decrease in speed compared to mmWave networks. Sprint activated 5G service in Chicago on July 11, 2019. The company has also announced plans to deploy 5G in Los Angeles, CA, New York, NY, Phoenix, AZ, and Washington, DC.

T-Mobile USA has active 5G services in Atlanta, GA and Cleveland, OH, with future plans to bring 5G services to Dallas, TX, Los Angeles, CA, Las Vegas, NV, and New York, NY. T-Mobile’s deployment is powered by Ericcson AIR 3246 modems, which support both 4G LTE and 5G NR. This equipment allows for 5G and LTE networks to be operated from the same equipment.

The purchase of Sprint by T-Mobile has been approved by the Justice Department, though a multi-state lawsuit is aiming to prevent the deal from proceeding. If the merger goes forward, “only the New T-Mobile will be able to deliver… real, game-changing 5G,” according to T-Mobile CEO John Legere in a June 2019 blog post. Following a merger, the New T-Mobile will have 600 MHz low-band, 2.5 GHz mid-band, and mmWave spectrum holdings, putting it at an advantage relative to AT&T and Verizon.

Where is 5G available in the UK?

EE debuted 5G services in Belfast, Birmingham, Cardiff, Edinburgh, London, and Manchester on May 30, 2019. Availability of 5G by the end of 2019 is planned for Bristol, Coventry, Glasgow, Hull, Leeds, Leicester, Liverpool, Newcastle, Nottingham, and Sheffield. Availability of 5G in 2020 is planned for Aberdeen, Cambridge, Derby, Gloucester, Peterborough, Plymouth, Portsmouth, Southampton, Wolverhampton, and Worcester.

BT, which owns EE, is anticipated to deploy separate BT-branded 5G services in London, Manchester, Edinburgh, Birmingham, Cardiff, and Belfast in autumn 2019.

Vodafone provides 5G services in Birkenhead, Birmingham, Bolton, Bristol, Cardiff, Gatwick, Glasgow, Lancaster, Liverpool, London, Manchester, Newbury, Plymouth, Stoke-on-Trent, and Wolverhampton at present, with deployments planned for Blackpool, Bournemouth, Guildford, Portsmouth, Reading, Southampton, and Warrington by the end of 2019.

Three will begin rollout of 5G services in London in August 2019, with services for Birmingham, Bolton, Bradford, Brighton, Bristol, Cardiff, Coventry, Derby, Edinburgh, Glasgow, Hull, Leeds, Leicester, Liverpool, Manchester, Middlesbrough, Milton Keynes, Nottingham, Reading, Rotherham, Sheffield, Slough, Sunderland, and Wolverhampton expected before the end of the year.

Three and Vodafone do not charge a premium for 5G network services in the UK, compared to their rate plans for 4G.

O₂ announced availability of 5G services for Belfast, Cardiff, Edinburgh, London, Slough, and Leeds “from October 2019,” with plans to bring expand 5G services to “parts of 20 towns and cities, before rolling out to a total of 50 by summer 2020.”

Where is 5G available in Australia?

Optus has 100 5G-capable sites in service, and has pledged to build 1,200 by March 2020.

Telstra commenced rollout of 5G networks, starting with the Gold Coast in August 2018. Telstra services select neighborhoods in Adelaide, Brisbane, Canberra, Gold Coast, Hobart, Launceston, Melbourne, Perth, Sydney, and Toowoomba.

Australia’s National Broadband Network (NBN) operator has declared its intent to provide 5G fixed wireless internet access in a statement to ZDNet.

Chinese vendors Huawei and ZTE have been banned by the Australian government from providing 5G networking equipment to mobile network operators due to national security concerns.

Where else in the world is 5G available?

South Korea was the first country to have a commercially available 5G network, with SK Telecom, KT, and LG Uplus activating 5G networks on April 3, 2019, two hours before Verizon Wireless activated 5G in the US, according to ZDNet’s Cho Mu-Hyun. By April 30, 2019, 260,000 subscribers in South Korea were using 5G networks. KT, the country’s second-largest mobile carrier, is working on deployments of in-building repeaters for use in crowded buildings such as airports and train stations.

5G is also seen as vital for economic development among Gulf states, with Saudi Arabia including 5G as part of the Vision 2030 economic development plan, and Qatari network operator Ooredoo claiming “the first commercially available 5G network in the world” on May 14, 2018, prior to the availability of smartphones that can use 5G.

Ookla maintains a map of 5G network services worldwide, with networks categorized into Commercial Availability, Limited Availability, and Pre-Release to demonstrate the extent of availability for each observed deployment.

How does a 5G future affect enterprises and mobile users?

As technology advances, older devices will inevitably reach end-of-life; in the mobile space, this is an outsized concern, as wireless spectrum is a finite resource. Much in the same way that the digital switchover occurred for over-the-air TV broadcasts, older mobile networks are actively being dismantled to free spectrum for next-generation networks, including transitional LTE Advanced, LTE Advanced Pro, and “true” 5G networks.

In the US, AT&T disabled its 2G network on January 1, 2017, rendering countless feature phones—as well as the original iPhone—unusable. Verizon plans to disable its legacy 2G and 3G networks by the end of 2019, which will render most feature phones and older smartphones unusable, as well as IoT devices such as water meters. Verizon stopped activations of 3G-only phones in July 2018. End-of-life plans for the 2G networks of Sprint and T-Mobile have not been publicly disclosed.

Additionally, as 5G is used increasingly to deliver wireless broadband, wireline broadband providers will face competition as the two services approach feature parity. With many people using smartphones both as their primary computing device and for tethering a traditional computer to the internet, the extra cost of a traditional wireline connection may become unnecessary for some people, and enable those outside the reach of traditional wireline connections to have affordable access to high-speed for the first time.

Business customers may also integrate 5G technology in proximity-targeted marketing. 5G’s reliance on microcells can be used as a secondary means of verification to protect against GPS spoofing, making proximity-targeted marketing resistant to abuse.

As 5G specifications are designed around the needs of businesses, the low-power and low-latency attributes are expected to spark a revolution in IoT deployments. According to Verizon Wireless President Ronan Dunne, 5G will enable the deployment of 20 billion IoT devices by 2020, leading to the creation of the “industrial internet,” affecting supply chain management, as well as agriculture and manufacturing industries. These same attributes also make 5G well suited to use cases that require continuous response and data analysis, such as autonomous vehicles, traffic control, and other edge computing use cases.

Source: https://clearcritique.com/5g-mobile-networks-a-cheat-sheet/

Five wireless inventions that define 5G NR — the global 5G standard

13 Aug

3GPP standardization efforts to develop a global specification for this unified, more capable wireless air interface called 5G New Radio (5G NR) have been ongoing since March 2016. And this week, at a 3GPP RAN Plenary meeting in Lisbon, Portugal, it is expected that 3GPP will successfully complete the first 5G NR specification — a significant industry milestone toward making 5G NR a commercial reality in 2019. This first 5G NR specification not only supports 2019 enhanced mobile broadband deployments, it also establishes the foundation for expanding 5G networks to virtually every industry, every object, and every connection.

So, what wireless technologies define this first 5G NR specification?

5G NR must meet an expanding and radically diverse set of connectivity requirements and deployment types. 5G NR also needs to get the most out of every bit of spectrum across a wide array of available spectrum regulatory paradigms and bands — from low bands below 1 GHz, to mid bands from 1 GHz to 10 GHz, to high bands above 24 GHz loosely known as millimeter-wave (mmWave). Therefore, there is no one single technology component that defines 5G NR. Instead, 5G NR will be built out of multiple technology inventions.

At Qualcomm, we have been developing these 5G building blocks for years — inventing new 5G technologies that are pushing, and often redefining, the boundaries of wireless. One of the most rewarding aspects of my work in Qualcomm Research is seeing our advanced system designs and wireless techniques progress from theory through design, standardization, implementation, and ultimately commercialization. And now, with the first 5G NR specification about to be completed, we are seeing our wireless technology inventions (summarized in Figure 1 below), make 5G NR — and our 5G vision — a reality.


Figure 1: Five wireless inventions that define 5G NR

Invention #1: Scalable OFDM numerology with 2n scaling of subcarrier spacing

One of the foremost decisions for 5G NR design is the choice of radio waveforms and multiple access techniques. While many approaches have been evaluated and will continue to be, we have found through extensive studies (published in a Qualcomm Research paper in November 2015) that the OFDM family — specifically CP-OFDM1 and DFT-Spread (DFT-S) OFDM2, are the right choices for 5G enhanced mobile broadband (eMBB) and beyond.

Since OFDM is used today, you might ask where’s the further innovation? One key 5G NR innovation is scalable OFDM multi-tone numerology (Figure 2). Today, LTE supports carrier bandwidths up to 20 MHz with a mostly fixed OFDM numerology of 15 kHz spacing between OFDM tones (often called subcarriers). With 5G NR, we have introduced scalable OFDM numerology to support diverse spectrum bands/types and deployment models. For example, 5G NR must be able to operate in mmWave bands that have wider channel widths (e.g., 100s of MHz). 3GPP 5G NR Rel-15 specification will utilize scalable OFDM numerology with 2N scaling of subcarrier spacing that can scale with the channel width, so the FFT size scales such that processing complexity does not increase unnecessarily for wider bandwidths.


Figure 2: Scalable OFDM multi-tone numerology

 

Invention #2: Flexible self-contained slot structure

Another key component of the 5G NR design is a flexible slot-based framework that will allow network operators to efficiently multiplex the envisioned (and unforeseen) 5G services on the same frequency. A key technology invention to deliver this flexible framework is the 5G NR self-contained slot structure. With the new self-contained slot structure (see TDD example in Figure 3 below), each 5G NR transmission is a modular transaction with the ability to independently decode slots and avoid static timing relationships across slots. By confining transmissions in time and frequency, the flexible design simplifies adding new 5G NR features/services in future — delivering a more forward-compatible design than previous generations.

The 5G NR self-contained slot structure also delivers significantly lower latency than LTE thanks to support for fast UL/DL turn-around and scalable slot durations of e.g. 500 µs at 30 kHz tone spacing to 125 µs at 120 kHz tone spacing. This slot structure framework includes the opportunity for UL/DL scheduling, data, and acknowledgement to occur in the same slot. Beyond lower latency, this modular slot structure design enables more adaptive TDD UL/DL configuration, advanced reciprocity-based antenna techniques (e.g., downlink Massive MIMO steering based on fast uplink sounding) as well as additional use cases enabled by adding subframe headers (e.g., contention resolution headers for shared/unlicensed spectrum) — making this invention, which is part of the 3GPP 5G NR specification, a key enabler to meeting many of the 5G NR requirements.


Figure 3: Benefits of the 5G NR TDD self-contained slot structure

 

Invention #3: Advanced ME-LDPC and CA-Polar channel coding

Along with the scalable numerology and flexible framework for 5G NR services, the physical layer design should include an efficient channel coding scheme that can provide robust performance and flexibility. Although Turbo codes have been well suited for 3G and 4G, Qualcomm Research has demonstrated that low-density parity check (LDPC) codes, and specifically advanced Multi-Edge LDPC (ME-LDPC) codes pioneered by Qualcomm Technologies, have advantages from both complexity and implementation standpoints when scaling to very high throughputs and larger block lengths as demonstrated in Figure 4. As a result, the 3GPP 5G NR Rel-15 specification will utilize ME-LDPC as the coding scheme for the eMBB data channel.

In addition, 3GPP selected Polar channel coding as the coding scheme for the eMBB control channel. Performance gains of CRC-Aided Polar (CA-Polar) channel coding, with significant design contributions from Qualcomm Technologies, led to its adoption across many 5G NR control use cases.


Figure 4: Throughput scaling with advanced ME-LDPC codes

 

Invention #4: Massive MIMO

Our 5G design is also advancing MIMO antenna technologies. By using more antennas intelligently, one can improve both network capacity and coverage. That is, more spatial data streams can significantly increase spectral efficiency (e.g., with multiuser massive MIMO), allowing more bits to be transmitted per Hertz, and smart beamforming techniques can extend the reach of base stations by focusing RF energy in specific directions on the downlink and similarly enabling the base station receiver to capture energy from a specific direction with less noise and interference on the uplink.

5G NR massive MIMO technology will make use of 2D antenna arrays at the base station capable of 3D beamforming, to make use of the higher frequency bands of mid-band spectrum. Accurate and timely channel knowledge is essential to realizing the full benefits of this 3D beamforming. Our optimized design for fast reciprocity-based TDD Massive MIMO, which is part of the 5G NR specification, will make use of the self-contained slot structure and enhanced Reference Signals to support much faster and more accurate channel feedback. Our test results have shown that it is possible to reuse existing macro cell sites (e.g., at 2 GHz) for new 5G NR deployments that operate in mid-bands between 3 GHz and 5 GHz. Our test results with new multiuser user 5G NR massive MIMO designs have shown significant gains in both capacity and cell-edge user throughput as shown in Figure 5, which is key to delivering a more uniform 5G mobile broadband user experience.


Figure 5: 5G NR massive MIMO simulations

 

Invention #5: Mobile mmWave

Our 5G NR design does not only enable the use of higher frequencies in mid-band spectrum for macro/small cell deployments, but it will also bring new mmWave opportunities at spectrum bands above 24 GHz for mobile broadband. The abundant spectrum available at these high frequencies supports extreme data speeds and capacity that will reshape the mobile experience. However, increased propagation loss, susceptibility to blockage (e.g., hand, head, body, foliage, building penetration), and RFIC complexity and power-efficiency, has historically made these high-bands not feasible for mobile communications. That is, until now. 5G NR mmWave is changing this, and Qualcomm is leading the way.

We have been working many years on the key design elements necessary to harness mmWave bands for usage in mobile broadband communication systems — proving to both ourselves and the industry what is feasible. As we demonstrated at Mobile World Congress earlier this year, our Qualcomm Research 5G mmWave prototype system (Figure 6 below) is utilizing a large number of antenna elements in both the base station and the device, along with intelligent/fast beamforming and beam-tracking algorithms, to showcase sustained broadband communications even for non-line-of-sight communications and device mobility.  Although there is still work to do, we are confident that we can achieve this next big moment in the mobile industry, making 5G NR mmWave a commercial reality in 2019 mobile networks and mobile devices, including smartphones.


Figure 6: Qualcomm Research 5G mmWave prototype system operating at 28 GHz

 

And that’s only the beginning…

The 3GPP Release-15 5G NR specification will establish the foundation for enhanced mobile broadband and beyond, but the 5G technology roadmap has just begun. We have already begun work on many new technology inventions that will drive future evolution and expansion of 5G NR networks and devices. Pioneering new technologies like 5G NR Spectrum Sharing to unlock more spectrum and support new deployment types, 5G NR Ultra-Reliable Low-Latency Communications (URLLC) to support new mission-critical services, 5G NR Cellular-V2X (C-V2X) to bring new capabilities for automated driving, 5G NR Integrated Access and Backhaul (IAB) to reduce backhaul costs more efficient network densification, and 5G NR massive IoT (mIoT) to address the low-power, wide-area Internet of Things.

Want to learn more about these five 5G NR inventions and what’s coming next? Download our new presentation — Making 5G NR a Commercial Reality.

 

1 OFDM waveform with Cyclic-Prefix insertion to help maintain orthogonality despite multi-path fading – utilized in LTE DL today

2 Use of DFT spreading to produce single-carrier OFDM waveform to reduce power variations in uplink – utilized in LTE UL today

Qualcomm Research is a division of Qualcomm Technologies, Inc.

Source: https://www.rcrwireless.com/20171220/5g/five-wireless-inventions-define-5g-nr-global-5g-standard

5G Mobile Wireless Technology

18 Nov

The new 5G mobile communications system will enable many new mobile capabilities to be realised – offering high speed, enormous capacity, IoT capability, low latency and much more it provides the bearer for many new applications.

 

The 5G mobile cellular communications system provides a far higher level of performance than the previous generations of mobile communications systems.

The new 5G technology is not just the next version of mobile communications, evolving from 1G to 2G, 3G, 4G and now 5G.

Instead 5G technology is very different. Previous systems had evolved driven more by what could be done with the latest technology. The new 5G technology has been driven by specific uses ad applications.

5G has been driven by the need to provide ubiquitous connectivity for applications as diverse as automotive communications, remote control with haptic style feedback, huge video downloads, as well as the very low data rate applications like remote sensors and what is being termed the IoT, Internet of Things.

5G Mobile Technology

5G standardisation

The current status of the 5G technology for cellular systems is very much in the early development stages. Very many companies are looking into the technologies that could be used to become part of the system. In addition to this a number of universities have set up 5G research units focussed on developing the technologies for 5G

In addition to this the standards bodies, particularly 3GPP are aware of the development but are not actively planning the 5G systems yet.

Many of the technologies to be used for 5G will start to appear in the systems used for 4G and then as the new 5G cellular system starts to formulate in a more concrete manner, they will be incorporated into the new 5G cellular system.

The major issue with 5G technology is that there is such an enormously wide variation in the requirements: superfast downloads to small data requirements for IoT than any one system will not be able to meet these needs. Accordingly a layer approach is likely to be adopted. As one commentator stated: 5G is not just a mobile technology. It is ubiquitous access to high & low data rate services.

5G cellular systems overview

As the different generations of cellular telecommunications have evolved, each one has brought its own improvements. The same will be true of 5G technology.

  • First generation, 1G:   These phones were analogue and were the first mobile or cellular phones to be used. Although revolutionary in their time they offered very low levels of spectrum efficiency and security.
  • Second generation, 2G:   These were based around digital technology and offered much better spectrum efficiency, security and new features such as text messages and low data rate communications.
  • Third generation, 3G:   The aim of this technology was to provide high speed data. The original technology was enhanced to allow data up to 14 Mbps and more.
  • Fourth generation, 4G:   This was an all-IP based technology capable of providing data rates up to 1 Gbps.

Any new 5th generation, 5G cellular technology needs to provide significant gains over previous systems to provide an adequate business case for mobile operators to invest in any new system.

Facilities that might be seen with 5G technology include far better levels of connectivity and coverage. The term World Wide Wireless Web, or WWWW is being coined for this.

For 5G technology to be able to achieve this, new methods of connecting will be required as one of the main drawbacks with previous generations is lack of coverage, dropped calls and low performance at cell edges. 5G technology will need to address this.

5G requirements

As work moves forwards in the standards bodies the over-riding specifications for the mobile communications system have been defined by the ITU as part of IMT2020.

The currently agreed standards for 5G are summarised below:

 

SUGGESTED 5G WIRELESS PERFORMANCE
PARAMETER SUGGESTED PERFORMANCE
Peak data rate At least 20Gbps downlink and 10Gbps uplink per mobile base station. This represents a 20 fold increase on the downlink over LTE.
5G connection density At least 1 million connected devices per square kilometre (to enable IoT support).
5G mobility 0km/h to “500km/h high speed vehicular” access.
5G energy efficiency The 5G spec calls for radio interfaces that are energy efficient when under load, but also drop into a low energy mode quickly when not in use.
5G spectral efficiency 30bits/Hz downlink and 15 bits/Hz uplink. This assumes 8×4 MIMO (8 spatial layers down, 4 spatial layers up).
5G real-world data rate The spec “only” calls for a per-user download speed of 100Mbps and upload speed of 50Mbps.
5G latency Under ideal circumstances, 5G networks should offer users a maximum latency of just 4ms (compared to 20ms for LTE).

5G communications system

The 5G mobile cellular communications system will be a major shift in the way mobile communications networks operate. To achieve this a totally new radio access network and a new core network are required to provide the performance required.

  • 5G New Radio, 5G NR:   5G new radio is the new name for the 5G radio access network. It consists of the different elements needed for the new radio access network. Using a far more flexible technology the system is able to respond to the different and changing needs of mobile users whether they be a small IoT node, or a high data user, stationary or mobile.
  • 5G NextGen Core Network:   Although initial deployments of 5G will utilise the core network of LTE or possibly even 3G networks, the ultimate aim is to have a new network that is able to handle the much higher data volumes whilst also being able to provide a much lower level of latency.

5G technologies

There are many new 5G technologies and techniques that are being discussed and being developed for inclusion in the 5G standards.

These new technologies and techniques will enable 5G to provide a more flexible and dynamic service.

The technologies being developed for 5G include:

  • Millimetre-Wave communications:   Using frequencies much higher in the frequency spectrum opens up more spectrum and also provides the possibility of having much wide channel bandwidth – possibly 1 – 2 GHz. However this poses new challenges for handset development where maximum frequencies of around 2 GHz and bandwidths of 10 – 20 MHz are currently in use. For 5G, frequencies of above 50GHz are being considered and this will present some real challenges in terms of the circuit design, the technology, and also the way the system is used as these frequencies do not travel as far and are absorbed almost completely by obstacles. Different countries are allocating different spectrum for 5G.
  • Waveforms :   One key area of interest is that of the new waveforms that may be seen. OFDM has been used very successfully in 4G LTE as well as a number of other high data rate systems, but it does have some limitations in some circumstances. Other waveform formats that are being discussed include: GFDM, Generalised Frequency Division Multiplexing, as well as FBMC, Filter Bank Multi-Carrier, UFMC, Universal Filtered MultiCarrier. There is no perfect waveform, and it is possible that OFDM in the form of OFDMA is used as this provides excellent overall performance without being too heavy on the level of processing required.
  • Multiple Access:   Again a variety of new access schemes are being investigated for 5G technology. Techniques including OFDMA, SCMA, NOMA, PDMA, MUSA and IDMA have all been mentioned. As mentioned above it appears that the most likely format could be OFDMA
  • Massive MIMO with beamsteering:   Although MIMO is being used in many applications from LTE to Wi-Fi, etc, the numbers of antennas is fairly limited. Using microwave frequencies opens up the possibility of using many tens of antennas on a single equipment becomes a real possibility because of the antenna sizes and spacings in terms of a wavelength. This would enable beams to be steered to provide enhanced performance.
  • Dense networks:   Reducing the size of cells provides a much more overall effective use of the available spectrum. Techniques to ensure that small cells in the macro-network and deployed as femtocells can operate satisfactorily are required. There is a significant challenge in adding huge numbers of additional cells to a network, and techniques are being developed to enable this.

These are a few of the main techniques being developed and discuss for use within 5G.

5G timeline & dates

5G is developoing rapidly and it needs to meet some demanding timelines. Some trial deployments have occurred and some of the first real deploymets are anticipayed in 2020.

Many countries are rushing to deply 5G as effective communications enable economimc growth and are seen as an essential element of modern day life and industry.

5G is rapidly developing and it is becoming the technology that everyone is moving towards. Not only will it be able to accommodate the superfast speeds required of it, but it will also be possible to accommodate the low data rate requiremets for IoT and IIoT applications. As such 5G will be able to encompass a huge number of different applications, and accommodate very many differnet data types.

The new 5G mobile communications system will enable many new mobile capabilities to be realised – offering high speed, enormous capacity, IoT capability, low latency and much more it provides the bearer for many new applications.

The 5G mobile cellular communications system provides a far higher level of performance than the previous generations of mobile communications systems.

The new 5G technology is not just the next version of mobile communications, evolving from 1G to 2G, 3G, 4G and now 5G.

Instead 5G technology is very different. Previous systems had evolved driven more by what could be done with the latest technology. The new 5G technology has been driven by specific uses ad applications.

5G has been driven by the need to provide ubiquitous connectivity for applications as diverse as automotive communications, remote control with haptic style feedback, huge video downloads, as well as the very low data rate applications like remote sensors and what is being termed the IoT, Internet of Things.

5G standardisation

The current status of the 5G technology for cellular systems is very much in the early development stages. Very many companies are looking into the technologies that could be used to become part of the system. In addition to this a number of universities have set up 5G research units focussed on developing the technologies for 5G

In addition to this the standards bodies, particularly 3GPP are aware of the development but are not actively planning the 5G systems yet.

Many of the technologies to be used for 5G will start to appear in the systems used for 4G and then as the new 5G cellular system starts to formulate in a more concrete manner, they will be incorporated into the new 5G cellular system.

The major issue with 5G technology is that there is such an enormously wide variation in the requirements: superfast downloads to small data requirements for IoT than any one system will not be able to meet these needs. Accordingly a layer approach is likely to be adopted. As one commentator stated: 5G is not just a mobile technology. It is ubiquitous access to high & low data rate services.

5G cellular systems overview

As the different generations of cellular telecommunications have evolved, each one has brought its own improvements. The same will be true of 5G technology.

  • First generation, 1G:   These phones were analogue and were the first mobile or cellular phones to be used. Although revolutionary in their time they offered very low levels of spectrum efficiency and security.
  • Second generation, 2G:   These were based around digital technology and offered much better spectrum efficiency, security and new features such as text messages and low data rate communications.
  • Third generation, 3G:   The aim of this technology was to provide high speed data. The original technology was enhanced to allow data up to 14 Mbps and more.
  • Fourth generation, 4G:   This was an all-IP based technology capable of providing data rates up to 1 Gbps.

Any new 5th generation, 5G cellular technology needs to provide significant gains over previous systems to provide an adequate business case for mobile operators to invest in any new system.

Facilities that might be seen with 5G technology include far better levels of connectivity and coverage. The term World Wide Wireless Web, or WWWW is being coined for this.

For 5G technology to be able to achieve this, new methods of connecting will be required as one of the main drawbacks with previous generations is lack of coverage, dropped calls and low performance at cell edges. 5G technology will need to address this.

5G requirements

As work moves forwards in the standards bodies the over-riding specifications for the mobile communications system have been defined by the ITU as part of IMT2020.

The currently agreed standards for 5G are summarised below:

SUGGESTED 5G WIRELESS PERFORMANCE
PARAMETER SUGGESTED PERFORMANCE
Peak data rate At least 20Gbps downlink and 10Gbps uplink per mobile base station. This represents a 20 fold increase on the downlink over LTE.
5G connection density At least 1 million connected devices per square kilometre (to enable IoT support).
5G mobility 0km/h to “500km/h high speed vehicular” access.
5G energy efficiency The 5G spec calls for radio interfaces that are energy efficient when under load, but also drop into a low energy mode quickly when not in use.
5G spectral efficiency 30bits/Hz downlink and 15 bits/Hz uplink. This assumes 8×4 MIMO (8 spatial layers down, 4 spatial layers up).
5G real-world data rate The spec “only” calls for a per-user download speed of 100Mbps and upload speed of 50Mbps.
5G latency Under ideal circumstances, 5G networks should offer users a maximum latency of just 4ms (compared to 20ms for LTE).

5G communications system

The 5G mobile cellular communications system will be a major shift in the way mobile communications networks operate. To achieve this a totally new radio access network and a new core network are required to provide the performance required.

  • 5G New Radio, 5G NR:   5G new radio is the new name for the 5G radio access network. It consists of the different elements needed for the new radio access network. Using a far more flexible technology the system is able to respond to the different and changing needs of mobile users whether they be a small IoT node, or a high data user, stationary or mobile.
  • 5G NextGen Core Network:   Although initial deployments of 5G will utilise the core network of LTE or possibly even 3G networks, the ultimate aim is to have a new network that is able to handle the much higher data volumes whilst also being able to provide a much lower level of latency.

5G technologies

There are many new 5G technologies and techniques that are being discussed and being developed for inclusion in the 5G standards.

These new technologies and techniques will enable 5G to provide a more flexible and dynamic service.

The technologies being developed for 5G include:

  • Millimetre-Wave communications:   Using frequencies much higher in the frequency spectrum opens up more spectrum and also provides the possibility of having much wide channel bandwidth – possibly 1 – 2 GHz. However this poses new challenges for handset development where maximum frequencies of around 2 GHz and bandwidths of 10 – 20 MHz are currently in use. For 5G, frequencies of above 50GHz are being considered and this will present some real challenges in terms of the circuit design, the technology, and also the way the system is used as these frequencies do not travel as far and are absorbed almost completely by obstacles. Different countries are allocating different spectrum for 5G.
  • Waveforms :   One key area of interest is that of the new waveforms that may be seen. OFDM has been used very successfully in 4G LTE as well as a number of other high data rate systems, but it does have some limitations in some circumstances. Other waveform formats that are being discussed include: GFDM, Generalised Frequency Division Multiplexing, as well as FBMC, Filter Bank Multi-Carrier, UFMC, Universal Filtered MultiCarrier. There is no perfect waveform, and it is possible that OFDM in the form of OFDMA is used as this provides excellent overall performance without being too heavy on the level of processing required.
  • Multiple Access:   Again a variety of new access schemes are being investigated for 5G technology. Techniques including OFDMA, SCMA, NOMA, PDMA, MUSA and IDMA have all been mentioned. As mentioned above it appears that the most likely format could be OFDMA
  • Massive MIMO with beamsteering:   Although MIMO is being used in many applications from LTE to Wi-Fi, etc, the numbers of antennas is fairly limited. Using microwave frequencies opens up the possibility of using many tens of antennas on a single equipment becomes a real possibility because of the antenna sizes and spacings in terms of a wavelength. This would enable beams to be steered to provide enhanced performance.
  • Dense networks:   Reducing the size of cells provides a much more overall effective use of the available spectrum. Techniques to ensure that small cells in the macro-network and deployed as femtocells can operate satisfactorily are required. There is a significant challenge in adding huge numbers of additional cells to a network, and techniques are being developed to enable this.

These are a few of the main techniques being developed and discuss for use within 5G.

5G timeline & dates

5G is developoing rapidly and it needs to meet some demanding timelines. Some trial deployments have occurred and some of the first real deploymets are anticipayed in 2020.

Many countries are rushing to deply 5G as effective communications enable economimc growth and are seen as an essential element of modern day life and industry.

5G is rapidly developing and it is becoming the technology that everyone is moving towards. Not only will it be able to accommodate the superfast speeds required of it, but it will also be possible to accommodate the low data rate requiremets for IoT and IIoT applications. As such 5G will be able to encompass a huge number of different applications, and accommodate very many differnet data types.

5G NextGen Core Network

The 5G NG NextGen core network will play a crucial role in enabling the overall performance of the 5G mobile communications system to meet its performance goals.

 

The 5G NextGen, NG core network will play a key role in enabling the performance of the 5G mobile communications system.

Defining the next-generation architecture is the responsibility of the 3GPP’s System Architecture (SA) Technical Specification Group on Service and System Aspects.

The study phase, completed last year in 2016, outlines what this new core network, known as NG Core, or NextGen core network, will look like.

5G NextGen NG core network basics

The requirements for the network for 5G will be particularly diverse. In one instance, very high bandwidth communications are needed, and in other applications there is a need for exceedingly low latency, and then there are also requirements for low data rate communications for machine to machine and IoT applications.

In amongst this there will be normal voice communications, Internet surfing and all the other applications that we have used and become accustomed to using.

As a result the 5G NextGen network will need to accommodate a huge diversity in types of traffic and it will need to be able to accommodate each one with great efficiency and effectiveness. Often it is thought that type suits all approach does not give the optimum performance in any application, but this is what is needed for the 5G network.

To achieve the requirements for the 5G network a number of techniques are being employed. These will make the 5G network considerably more scalable, flexible and efficient.

  • Software defined networking, SDN:   Using software defined networks, it is possible to run the network using software rather than hardware. This provides significant improvements in terms of flexibility and efficiency
  • Network functions virtualisation, NFV :   When using software defined networks it is possible to run the different network function purely using software. This means that generic hardware can be reconfigured to provide the different functions and it can be deployed as required on the network.
  • Network slicing:   As 5G will require very different types of network for the different applications, a scheme known as network slicing has been devices. Using SDN and NFV it will be possible to configure the type of network that an individual user will require for his application. In this way the same hardware using different software can provide a low latency level for one user, whilst providing voice communications for another using different software and other users may want other types of network performance and each one can have a slice of the network with the performance needed.

The performance required for the 5G NextGen network has been defined by the NGMN (Next Generation Mobile Network Alliance). The Next Generation Mobile Networks Alliance is a mobile telecommunications association of mobile operators, vendors, manufacturers and research institutes and by using the experience of all parties, it is able to develop the strategies for the next generation mobile networks, like that for 5G.

As such the 5G NG, NextGen core network will be able to utilise far greater levels of flexibility to enable it to serve the increased and diverse requirements placed upon it by the radio access network and the increased number of connections and traffic.

5G Waveform: CP-OFDM & DFT-SOFDM

The waveform that has been adopted for the 5G New Radio is based on OFDM but with updates to that used with LTE

 

The standard for the 5G New Radio phase one has been released and within this the waveform to be used has been defined.

A number of candidate waveforms were investigated for 5G, and after much discussion it was decided that a waveform based n OFDM would provide the optimum results.

Accordingly cyclic prefix OFDM, or CP-OFDM was chosen as the main candidate with DFT-SOFDM, discrete Fourier transform spread orthogonal frequency division multiplexing being used in some areas.

5G waveform background

Orthogonal frequency division multiplexing has been an excellent waveform choice for 4G. It provides excellent spectrum efficiency, it can be processed and handled with the processing levels achievable in current mobile handsets, and it operates well with high data rate stream occupying wide bandwidths. It operates well in situations where there is selective fading.

However with the advances in processing capabilities that will be available by 2020 when 5G is expected to have its first launches means that other waveforms can be considered.

There are several advantages to the use of new waveforms for 5G. OFDM requires the use of a cyclic prefix and this occupies space within the data streams. There are also other advantages that can be introduced by using one of a variety of new waveforms for 5G.

One of the key requirements is the availability of processing power. Although Moore’s Law in its basic form is running to the limits of device feature sizes and further advances in miniaturisation are unlikely for a while, other techniques are being developed that mean the spirit of Moore’s Law is able to continue and processing capability will increase. As such new 5G waveforms that require additional processing power, but are able to provide additional advantages are still viable.

5G waveform requirements

The potential applications for 5G including high speed video downloads, gaming, car-to-car / car-to-infrastructure communications, general cellular communications, IoT / M2M communications and the like, all place requirements on the form of 5G waveform scheme that can provide the required performance.

Some of the key requirements that need to be supported by the modulation scheme and overall waveform include:

  • Capable of handling high data rate wide bandwidth signals
  • Able to provide low latency transmissions for long and short data bursts, i.e. very short Transmission Tine Intervals, TTIs, are needed.
  • Capable of fast switching between uplink and downlink for TDD systems that are likely to be used.
  • Enable the possibility of energy efficient communications by minimising the on-times for low data rate devices.

These are a few of the requirements that are needed for 5G waveforms to support the facilities that are needed.

Cyclic Prefix OFDM: CP-OFDM

The specific version of OFDM used in 5G NR downlink is cyclic prefix OFDM, CP-OFDM and it is the same waveform LTE has adopted for the downlink signal.

Basic concept of OFDM, Orthogonal Frequency Division Multiplexing used in 5G NR, showing how the sidebands from adjacent carriers cancel at the point of the main carriers
Basic concept of OFDM, Orthogonal Frequency Division Multiplexing

The 5G NR uplink has used a different format to 4G LTE. CP-OFDM- and DFT-S-OFDM-based waveforms are used in the uplink. Additionally, 5G NR provides for the use of flexible subcarrier spacing. LTE subcarriers normally had a 15 kHz spacing, but 5G NR allows the subcarriers to be spaced at 15 kHz x 2s with a maximum spacing of 240 kHz. The integral s carrier spacing rather than fractional carrier spacing is required to preserve the orthogonality of the carriers.

The flexible carrier spacing is used to properly support the diverse spectrum bands/types and deployment models that 5G NR will need to accommodate. For example, 5G NR must be able to operate in mmWave bands that have wider channel widths of up to 400 MHz. 3GPP 5G NR Rel-15 specification details the scalable OFDM numerology with 2s scaling of subcarrier spacing that can scale with the channel width, so the FFT size scales so that processing complexity does not increase unnecessarily for wider bandwidths. The flexible carrier spacing also gives additional resilience to the effects of phase noise within the system.

The use of OFDM waveforms offers a lower implementation complexity compared to that which would be needed if some of the other waveforms considered for 5G had been implemented. In addition to this, OFDM is well understood as it has been used for 4G and many other wireless systems.

5G Modulation Schemes

– the modulation scheme or schemes adopted for 5G will play a major role in determining the performance and complexity of the handsets and other nodes used.

 

The modulation schemes used for 5G will have a major impact on performance.

Whilst there are requirements to ensure that the data rates needed can be carried and the 5G modulation schemes performance issues including peak to average power ratio, spectral efficiency, and performance in the presence of interference and noise need to be included in any decisions made.

Peak to average power ratio, PAPR

The peak to average power ratio is one aspect of performance that needs to be considered for any 5G modulation scheme.

The peak to average ratio has a major impact on the efficiency of the power amplifiers. For 2G GSM, the signal level was constant and as a result it was possible to run the final RF amplifier in compression to obtain a high level of efficiency and maximise the battery life.

With the advent of 3G, then its HSPA enhancements and then 4G, the modulation schemes and waveforms have meant that the signals have become progressively more ‘peaky’ with higher levels of peak to average power ratio. This has meant that the final RF amplifiers cannot be run in compression and as the PAPR has increased, so the efficiency of the RF amplifiers has fallen and this is one factor that has shortened battery life.

The opportunity now arises to utilise 5G modulation schemes that can reduce the PAPR and thereby improve efficiency.

Spectral efficiency

One of the key issues with any form of 5G modulation scheme is the spectral efficiency. With spectrum being at a premium, especially in frequencies below 3 GHz, it is essential that any modulation scheme adopted for 5G is able to provide a high level of spectral efficiency.

There is often a balance between higher orders of modulation like 64 QAM as opposed to 16 QAM for example and noise performance. Thus higher order modulation schemes tend to be only sued when there is a good signal to noise ratio.

Accordingly any 5G modulation scheme will need to accommodate high levels of performance under a variety of conditions.

5G modulation schemes

3G and 4G have used modulation schemes including PSK and QAM. These schemes provide excellent spectral efficiency and have enabled the very high data rates to be carried but fall short in terms of their peak to average power ratio.

To overcome the PAPR issue, one option being considered for a 5G modulation scheme is APSK or amplitude Phase Shift Keying.

However in view of the fact that amplitude components of a signal are more subject to noise, which is substantially amplitude based, it is likely that any overall 5G modulation scheme will be adaptive, enabling the system to switch to the most optimum for of modulation for the given situation.

5G Multiple Access Schemes

– preliminary details and information about the multiple access schemes and technology being developed for 5th generation or 5G mobile wireless or cellular telecommunications systems.

 

One key element of any cellular communications system is the multiple access technology that is used.

As a result the 5G multiple access schemes are being carefully considered and researched to ensure that the optimum technique or techniques are adopted.

There are several candidate 5G multiple access schemes that are in the running. Each has its own advantages and disadvantages and as a result, no single technique is likely to meet all the requirements.

5G multiple access schemes

There are several candidate systems that are being considered as the 5G multiple access scheme. They include a variety of different ideas.

  • Orthogonal frequency division multiple access, OFDMA:   OFDMA has been widely used and very successful for 4G and could be used as a 5G multiple access scheme. However it does require the use of OFDM and requiring orthogonality between carriers and the use of a cyclic prefix has some drawbacks. As a result other multiple access schemes are being investigated.
  • Sparse Code Multiple Access, SCMA:   SCMA is another idea being considered as a 5G multiple access scheme and it is effectively a combination of OFDMA and CDMA. Normally with OFDMA a carrier or carriers is allocated to a given user. However if each carrier has a spreading code added to it, then it would be able to transmit data to or from multiple users. This technique has been developed to use what are termed sparse code and in this way significant numbers of users can be added while maintaining the spectral efficiency levels.
  • Non-orthogonal multiple access, NOMA:   NOMA is one of the techniques being considered as a 5G multiple access scheme. NOMA superposes multiple users in the power domain, using cancellation techniques to remove the more powerful signal. NOMA could use orthogonal frequency division multiple access, OFDMA or the discrete Fourier transform, DFT-spread OFDM. .

There are several multiple access schemes that could be used with 5G. The one or ones used will be chosen as a result of the standardisation process which is currently onging.

5G Millimetre Wave

– preliminary details and information the millimetre wave technologies being developed for 5G mobile communications

 

One of the options that is most likely to be incorporated into the 5G technologies that are being developed for the 5G cellular telecommunications systems is a millimetre wave capability.

With spectrum being in short supply below 4GHz, frequencies extending up to 60GHz are being considered.

5G millimetre wave basics

One of the interfaces being considered for 5G mobile communications uses millimetre wave frequencies.

It is estimated that bandwidths of several GHz may be required by operators to provide some of the extremely high data rates being forecast.

Currently frequency below 4GHz are being used by cellular communications systems, and by the very nature, these frequencies could only offer a maximum bandwidth of 4 GHz, even if they were all clear for use which is obviously not possible.

By having a 5G millimetre wave interface, much wider bandwidths are possible, and there are several candidate millimeter bands that are being considered for allocation to this type of service.

5G millimeter wave propagation

The propagation characteristics of millimetre wave bands are very different to those below 4GHz. Typically distances that can be achieved are very much less and the signals do not pass through walls and other objects in buildings.

Typically millimetre wave communication is likely to be used for outdoor coverage for dense networks – typically densely used streets and the like. Here, ranges of up to 200 or 300 metres are possible.

One of the issues of using millimetre wave signals is that they can also be affected by natural changes such as rain. This can cause a considerable reduction in signal levels for the duration of the precipitation. This may result in reduced coverage for some periods.

Often these 5G millimetre wave small cells may use beamforming techniques to target the required user equipment and also reduce the possibility of reflections, etc.

Millimetre wave coverage

Simulations have shown that when millimetre wave small cells are set up they provide a good level of coverage. Naturally, typically being lower down than macro cells, the coverage will not be as good, but when considering the level of data they can carry, they provide an excellent way forwards for meeting the needs of 5G systems.

A further issue to be considered when looking at 5G millimetre wave solutions is that they will incur a much greater number of handovers than a normal macro cell. The additional signalling and control needs to be accommodated within the system. Also backhaul issues need to be considered as well.

Source: https://www.electronics-notes.com/articles/connectivity/5g-mobile-wireless-cellular/technology-basics.php

3GPP Burns Midnight Oil for 5G

10 Sep

Long hours, streamlined features to finish draft. The race is on to deliver some form of 5G as soon as possible.

An Intel executive painted a picture of engineers pushing the pedal to the metal to complete an early version of the 5G New Radio (NR) standard by the end of the year. She promised that Intel will have a test system based on its x86 processors and FPGAs as soon as the spec is finished.

The 3GPP group defining the 5G NR has set a priority of finishing a spec for a non-standalone version by the end of the year. It will extend existing LTE core networks with a 5G NR front end for services such as fixed-wireless access.

After that work is finished, the radio-access group will turn its attention to drafting a standalone 5G NR spec by September 2018.

“Right now, NR non-standalone is going fine with lots of motivation, come hell or high water, to declare a standard by the end of December,” said Asha Keddy, an Intel vice president and general manager of its next-generation and standards group. “The teams don’t even break until 10 p.m. on many days, and even then, sometimes they have sessions after dinner.”

To lighten the load, a plenary meeting of the 3GPP radio-access group next week is expected to streamline the proposed feature set for non-standalone NR. While a baseline of features such as channel coding and subcarrier spacing have been set, some features are behind schedule for being defined, such as MIMO beam management, said Keddy.

It’s hard to say what features will be in or out at this stage, given that decisions will depend on agreement among carriers. “Some of these are hit-or-miss, like when [Congress] passes a bill,” she said.

It’s not an easy job, given the wide variety of use cases still being explored for 5G and the time frames involved. “We are talking about writing a standard that will emerge in 2020, peak in 2030, and still be around in 2040 — it’s kind of a responsibility to the future,” she said.

The difficulty is even greater given carrier pressure. For example, AT&T and Verizon have announced plans to roll out fixed-wireless access services next year based on the non-standalone 5G NR, even though that standard won’t be formally ratified until late next year.

N

An Intel 5G test system in the field. (Images: Intel)

An Intel 5G test system in the field. (Images: Intel)

Companies such as Intel and Qualcomm have been supplying CPU- and FPGA-based systems for use in carrier trials. They have been updating the systems’ software to keep pace with developments in 3GPP and carrier requests.

For its part, Intel has deployed about 200 units of its 5G test systems to date. They will be used on some of the fixed-wireless access trials with AT&T and Verizon in the U.S., as well as for other use cases in 5G trials with Korea Telecom and NTT Docomo in Japan.

Some of the systems are testing specialized use cases in vertical markets with widely varied needs, such as automotive, media, and industrial, with companies including GE and Honeywell. The pace of all of the trials is expected to pick up next year once the systems support the 5G non-standalone spec.

Intel’s first 5G test system was released in February 2016 supporting sub-6-GHz and mm-wave frequencies. It launched a second-generation platform with integrated 4×4 MIMO in August 2016.

The current system supports bands including 600–900 MHz, 3.3–4.2 GHz, 4.4–4.9 GHz, 5.1–5.9 GHz, 28 GHz, and 39 GHz. It provides data rates up to 10 Gbits/second.

Keddy would not comment on Intel’s plans for dedicated silicon for 5G either in smartphones or base stations.

In January, Intel announced that a 5G modem for smartphones made in its 14-nm process will sample in the second half of this year. The announcement came before the decision to split NR into the non-standalone and standalone specs.

Similarly, archrival Qualcomm announced late last year that its X50 5G modem will sample in 2017. It uses eight 100-MHz channels, a 2×2 MIMO antenna array, adaptive beamforming techniques, and 64 QAM to achieve a 90-dB link budget and works with a separate 28-GHz transceiver and power management chips.

Source: http://www.eetimes.com/document.asp?doc_id=1332248&page_number=2

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