Research On Coordinated Multiple Points In TDD System

Recently, CoMP has been a hot topic of discussion among communication scholars. By the introduction of collaboration between the base stations CoMP can reduce interference. Usually CoMP.Transmission can be classified into two parts, JP and CSCB. JP technology take the interference as useful signals by sharing data, channel information be-tween base stations, which can achieve the purpose of elimination of the adja-cent cell interference. CoMP-JT, also called CoMP Joint-transforming, is usu-ally used in the present CoMP-JP. CSCB technology avoids causing interference by allocation of resources. Considered Intra-site CSCB has a better performance, we use Intra-site CSCB in the computer simulation.As the innate reciprocity of TDD mode, it can be widely used in CoMP. We can reduce interference by using pre-coding methods in downlink MU-CoMP. ZF,BD,BD+SVD,MET algorithm’s complexity gradually increased, but the MET can reach better gain relative to other pre-coding algorithm, MET has more zero space dimensions,it can support more users pairing,so it has a better performance. CoMP is less sensitive to EVM, so CoMP has an advantage of certain anti-noise compared to other transmission technologies.In fact, we can never reach the ideal state of absolute reciprocity, adding the hardware conditions, CoMP often need to consider a variety of non-ideal factors, typically with SRS estimation errors, the antenna calibration error, the frequency offset between base stations. Conclusion shows these non-ideal fac-tors will bring varying degrees of loss on CoMP permance.SRS error make a great contribution to performance degradation, we should take SRS coordination to improve.users antenna calibration has few affects. antenna calibration error within and between base stations don’t make a great affect,while the phase error is within10degrees, the performance degradation is within5%.Frequency offset between base stations has a limit affect to CoMP, in fact, as hardwares can reach a high level, frequency offset between base stations has few affects.