5th generation radio access network is expected to meet the system after 2020 and demand for new services and applications and use cases. Interconnecting all walks of life and support new service is the most important aspect of 5G technology, in order to be ready to meet the 2020 requirements of the information society. 4th generation or 4G LTE mainly connected people and places, based on communication and information sharing as the core theme. 5G through communication and sharing of information relating to an increase 4G reliable, flexible control and monitoring functions, so as to extend the range of the connection to the equipment. This change of system requirements and design principles had a profound impact. 5G vision can say all-inclusive, involving all aspects of people's lives, will affect how people produce goods, how to manage the production process, energy and environment, how to transport, store and consumer goods, affecting how people live, work, commute, entertainment, and even relaxation and so on.
Therefore, the use of virtualization and software-defined network to challenge the 5G system / network performance limits, in order to ensure greater network capacity, higher user throughput, higher spectrum, higher bandwidth, lower latency , lower power consumption, higher reliability and higher connection density. 5G network architecture consists of modular functions. These functions can be deployed on demand and expand, thereby enabling a low cost way to meet the needs of a wide range of application cases.
4G LTE technology is very successful, very suitable spectrum below 6GHz. 5G is increased above 6GHz spectrum, a large section of opening for the unused spectrum radio access network. It also supports greater than the carrier 20MHz, lower control overhead and improve RAN flexibility to meet the needs of a variety of use cases. 6GHz spectrum support more than 5G technology is one of the most promising properties, perhaps the biggest characteristic difficulty. 6GHz above channel model in June 2016 issued by the 3GPP, the accuracy of the correct design base station and user equipment (UE) design plays a key role. The reality is that more work needs to be done to improve the accuracy and field testing of these models. During this period, the system design requires flexibility and programmability inherent to field experience adjustments and improvements in the underlying algorithms.
End delay will be reduced to less than 1ms is another important goal 5G, designed to meet mission-critical applications of ultra-high reliability and low latency (such as a commitment to bring service providers use cases, as well as the expansion of mobile broadband use cases higher incomes game) requirements. 5G is an improved frame structure to achieve the above goal. Figure 1 shows a standard frame structure of a quasi-5G scheme. Very short time of the transmission scheme having a 100-200 microsecond intervals (the TTI), 10 times shorter than the 4G LTE TTI (1ms), comprising a fast Hybrid ARQ (automatic repeat request) confirm, the system latency can be shortened . Front carrier demodulation using the reference signal and the control may be performed during the frame processing of the received frame, rather than the other buffer after the entire sub-frame reprocessing. The frame structure is also used to simplify and speed up fast scheduling requests per subframe. Therefore, the calculation of the desired baseband 5G 4G LTE system will significantly increase compared.
5G expected to support a flexible frame structure, to accommodate different applications and use cases, such as packet length and the end to end delay. There are two sub-frame extension method under consideration, they have a flexible number of symbols per subframe and the subframe length variable. The two methods can also be used in combination. Both methods support multiple types of transmission (downlink, uplink, and mixed mode). Subframe duration and sampling rate on the same baseline 5G digital definition. Flexible frame structure to achieve an effect on the physical (PHY) layer. See symbol by symbol, FFT and cyclic prefix lengths may be different. The number of symbols, the OFDM sub-carrier number and the number of QAM symbols on each physical resource blocks per subframe may be different in terms, guard period has a variable length and position. This can significantly increase the complexity of implementing 5G PHY's. At least in the early years, the most appropriate way to build the system should 5G utilizes programmable FPGA SoC with evolving standards and to expand and upgrade the system, according to the performance and implementation improvements measurements and adjustments site.
MIMO technology is well suited centimeter wave (3-30 GHz) and millimeter wave (30-300GHz) frequency, which is cheap and underutilized spectrum resources, a large number of available continuous band. The higher the frequency, the greater propagation loss of transmission signal. However, at higher frequencies can be obtained very narrow pencil beams, antenna gain can be greater to compensate for the higher propagation loss. Furthermore, as the carrier frequency, the size of the antenna element decreases. Thus, more antenna elements can be loaded in a smaller area. For example, 2.6GHz art antenna unit 20 comprises about one meter. In the 15GHz, it can be designed to have 200 units but only 5cm wide, 20cm high antenna. Antenna elements increases, the signal means can be accurately directed to the target receiver. Because the system in many forms such beam transmission focus in a specific direction, thus dramatically improved coverage and capacity.
Draft (New Radio) 5G NR specification does not specify the number of MIMO layers supported, but it may be up to 32 to 64 layers. 5G system will support the allocation of resources to users quickly re-configured in each TTI period, in order to achieve higher spectrum efficiency. When support for multiple MIMO layer, which will further increase the complexity of the system. Figure 2 shows the user the resource allocation example 5G MIMO system. Time division duplex (TDD) help to alleviate achieve 5G Massive MIMO, wherein the channel state information using channel reciprocity determined. The program is not linear CPE or a terminal in consideration. An important point need to specify, in the base station implementation, 5G, the terminal needs to record a plurality of beams and periodically request the base station for resource allocation for transmission of the uplink data assigned the best beam. When the terminal UE handover beam, need to recalculate the channel state information. In order to achieve such a complex system, be sure to introduce sufficient flexibility and programmability, to adjust implementations, achieve the desired performance for different terminals.
For deployments below 6GHz, 5G antenna system typically up to 64 units. There could be more than 6GHz number of antenna elements. Digital beam forming is generally used in the case of frequencies below 6GHz (implemented in the base band); and a combination of digital and analog hybrid scheme beamforming technology is used for frequencies above 6GHz. 64 comprises antenna elements arranged Massive MIMO system can significantly increase the complexity and cost, due to the support base band digital beam L1 to form the desired large number of active radio signal pre-coding strand and a calculation. Connection requires a sharp increase in the baseband signal chain between the RRU. To achieve these systems more economical, it is necessary to integrate part of the baseband signal processing or L1 in which the radio. This functional division future may result in the network node L1-L2 and the radio function is in the same position. Figure 3 illustrates the antenna element 64 is connected in claim Massive MIMO system functions on different boundaries, highlighting the need for co-located with the radio L1.
5G scope is quite broad, and the whole industry and very active, submitted hundreds of proposals, thus enabling significantly longer time to negotiate. Of the proposed algorithm and network configuration simulation, although this is good, but not enough. Concept demonstrations, field trials and test bench to assess these proposals are very critical. This makes it difficult to review all the general mechanism proposed. In addition, the pressure from the market is very huge, released earlier 5G specification requirements. For some operators plan to launch massive machine-type communication (mMTC) and ultra-high reliability and low latency use cases (URLLC) standardized extension unhappy - is expected to launch in late 2019. 3GPP has selected data for the LDPC, code for polarization selection eMBB use cases. For mMTC and URLLC use cases, LDPC, code and polarization turbo codes are being considered, but the industry will have to wait longer to make a conclusion for these use cases. In many cases, there is a user terminal and the base station may support multiple 5G 5G use cases, which makes it difficult to design the base band codec increase, higher costs.
To complicate matters, the operator is not clear how the use cases 5G is commercially deployed and which will be at the forefront of the market in deployments. Fixed wireless access (last mile replacement optical fiber) and Smart City are two industry leading use cases. Using URLLC of vertical integration and industrial automation and transportation also take longer to come out of the laboratory and limited field trials, achieve broader market applications. For these reasons, 5G system is expected to have sufficient flexibility and programmability to fine tune the system functionality and performance to achieve in these cases with the evolution of the employed and adapt to market realities.
All Programmable FPGA Xilinx SoC and play a key role in achieving 5G concept validation, verification, and testing station eMBB, URLLC and early commercialization Test mMTC use case. Commercial chips has not yet launched, ASIC can not be practiced in the early stages of standardization 5G. On Xilinx All Programmable FPGA and SoC platforms based terms, the key value is that the system can be dynamically adjusted to support any of the features and enhanced algorithm implementation. Manufacturers use these platforms to run field tests to measure the performance of the actual deployment environment, to optimize system implementation. The first wave of commercial 5G may have to rely on these systems to optimize the system. Xilinx UltraScale and UltraScale + All Programmable FPGA and SoC 5G designed to meet the market requirements of the design. For more information, please visit china.xilinx.com.
Original Address: https://www.eeboard.com/news/5g-9/
Search for "Love Bo.com" to pay attention, daily update development board, intelligent hardware, open source hardware, activities, etc., you can make you master. Recommended attention!
[WeChat scanning picture can be directly paid]
Our other product:
