An Implementation In FPGA Of An Adaptive V-BLAST MC-CDMA Base-band System With 4 Transmitters And 5 Receivers And A Study On Synchronization Techonogy Of LTE

MIMO technology can take advantage of multipath fading existing in the wireless channel. V-BLAST technology can divide a broad-band channel to some independent narrow-band sub-channels, MIMO and V-BLAST will greatly improve the capacity and spectrum efficiency of wireless system. MC-CDMA technology is an amalgamation of both OFDM and CDMA, which has strong anti-interference and anti-multipath abilities. To satisfy high requirements of different services, adaptive technology is proposed for its strong flexibility; therefore, an integrated single-user adaptive V-BLAST MC-CDMA base-band system with 4 senders and 5 receivers has been constructed by adopting these techniques.In this paper, the proposed system has functions of three modulations, which are QPSK,16QAM and 64QAM. For the transmitter,4 antennas all adopt 32 sub-carriers and OVSF code when SF=32; the MIMO channel is set as a flat rayleigh fading; and for the receiver,5 antennas all adopt the same sub-carriers and OVSF as those of the transmitter, and select square root V-BLAST detecting and equal combination methods.FPGA has good features of high throughput rate and flexible configuration and computing speed, which is very applicable for wireless communication system with high rate and real-time requirements, so, in this paper, the proposed base-band system is designed and implemented in Virtex4 Xilinx-VC4VSX55 with verilog programming, its BER performance is achieved by modelsim tool and other performances are synthesized by synplify pro, such as resource utilization,highest working frequency and time delay; it is verified that the system has good reliability, flexibility and real-time.This paper puts a great emphasis on finding out an optimal detection scheme, and square root V-BLAST detecting and decoding method is proposed. Square root algorithm mainly makes use of Cordic rotation to reduce the complexity of detecting, because Cordic rotation can avoid the complicated computing of pseudo-inverse; by combing the interference cancellation of V-BLAST, square root V-BLAST detecting and decoding method can ensure low BER performance, the receiver can successfully and accurately detect out the transmitting signals from the receiving signals, which is verified with simutlation results.This paper has discussed cell search and synchronization of LTE system, including the FDD and TDD transmissions of PSS (Prime Synchronization Signal) and SSS (Secondary Synchronization Signal) sequences and the generations of PSS and SSS, A Matlab simulation framework is given, t both SER (Symbol Error Rate) performances of both PSS and SSS transmitted in AWGN and Rayleigh channels are analyzed.