Research And Implementation Of The Precoding Technology Of Uplink LTE-Advanced Systems

Recently, three domestic operators are all deploying LTE commercial networks, and it’s expected to begin operation formally in succession. 3GPP proposed the evolution of LTE,named as LTE-Advanced(LTE-A). Closed-loop spatial multiplexing transmission mode is introduced into LTE-A, so uplink MIMO of up to 4 layers is supported. Due to the introduction of uplink MIMO, we need research on the design of its precoders.Firstly, the thesis introduces some PHY concepts in LTE-A uplink and a sort of technologies related to uplink MIMO, serving as a theoretical basis for the research of subsequent chapters.The thesis also studies the LTE-A uplink codebook-based precoding technology. The contents of this chapter is about codebook(CB) selection algorithm. Typical CB selection algorithms are suit for subcarrier or subband, therefore, this chapter compares the wideband PMI and subband PMI performance of several algorithms, categorized as metric-based or right-singular-matrix-based. An algorithm based on minimizing the max noise power is present to get better output SNR and superior BER performance.Additionally, the thesis delves into the LTE-A uplink non-codebook-based precoding technology. This chapter mainly focuses on a sort of precoding algorithms or solutions, which will transfer the channel by the use of diagonalization, triangulation or LR. Diagonalization precoding can eliminate the interference among streams, but requires additional power allocation process to enhance the "sick" subchannels. The latter two types of algorithms get better BER performance with equal power. Furthermore, based on EVD case, this chapter works on an improved LDLH precoding scheme. It’s designed in view of MMSE criterion, and we can further enhance the performance using power allocation process.Finally, the thesis designs a precoding hardware module using KC705 EP board.. The test of functional simulation and the BER performance under link test can verify the reasonableness of this design. The maximum operating frequency of this precoding circuit can reach 151.607 MHz, fulfilling the needs for uplink precoding.