The Research And Implementation Of TD-LTE Uplink

Mobile communication has been indispensable in people’s daily life.To meet the increasing demand of multimedia service,3GPP has proposed LTE system.It shows not only a less time delay,a faster data transmission speed,but also a larger coverage area than previous systems,which has brought mobile Internet an unprecedented development and made LTE itself the most powerful commercial mobile communication system.In this context,this paper focuses on the research and implementation of the TD-LTE uplink.Firstly,key techniques of LTE are descripted in detail.Then,channel estimation methods used in both pilot symbols and data symbols are discussed and compared.Channel estimation by adding virtual channel frequency response(VCFR)is selected for implementation on DSP based on the comparison.Besides,this paper highlights the implementation of PUSCH on TI C6670 multi-core DSP platform.The major contributions of this paper are as follows:Firstly,based on parallel computing mechanism,efficient code architecture of LTE-PUSCH is proposed to meet the demand of load balancing.What’s more,synchronization method is designed using semaphore and shared memory.Secondly,based on the in-depth study of channel estimation by adding VCFR in the scene of multi-user,a code structure is put forward with the character of fine grain and high parallelism to bring greater efficiency.Thirdly,a set of algorithm and software optimization solutions are designed which take into account the factors of precision and efficiency.Among them,a fix-point processing is proposed to offset the impact of FFTC accelerator’s output data scaling.In equalization module,an adaptive method is gave to replace division by table look-up,which takes small memory and avoids low efficiency division operations.Meanwhile,the specialized instruction and storage optimizations are carried out for platform of TI C6670.In general,the experiment result on the hardware platform proves that the implementation solution of PUSCH proposed in this paper is of great practical significance and engineering value.