Research On Device-to-device Relaying Technology For TD-LTE-A System

Along the technology development and personal requirement, the wirelesscommunication system has been evolved the fourth generation so called4G.TD-LTE standard designed and proposed by China has been accepted as candidatetechnology by the ITU. It is a vital task that to complete the standard and furtherimprove the system performance. Meanwhile, short-range communication has beenapplied in people’s daily life with the service diversity growing. Most pocket device,for instance, equips short-range communications module such as Bluetooth, WLAN,et al. A new type of communication, device-to-device(D2D), which allows usercommunicate with others directly underlying cellular network has been proposed inrecent years and attracts attentions of many researchers around the world. D2D hasbeen deemed as the scheme of enhance the LTE system by some organizations.For another, relay has been proposed as new features of LTE-A. It couldimprove the throughput of users who suffer from bad channel quality. Asaforementioned, D2D could support data transmission among users without relayingby base stations. Based on those factors, a new scheme which allows users-to-basestation link relayed by another user is proposed in this paper. With further utilizedidle users’ cooperation, the system could gain benefit on throughput from thedecode-forward relays. In addition, the frequency efficiency has been enhanced dueto the frequency reuse scheme.The proposed scheme has been designed totally according to the TD-LTE-Asystem in terms of relative technique specifications. Completely working process ofD2D cooperative relaying system has been designed. It contains the process frominitialization to the resource release. For the sake of coordinate the interferencebetween D2D link and cellular link caused by the frequency reuse, this paper alsoanalyze several working circumstance and introduces appropriate methods ofresource scheduling to solve the problem.Finally, this paper analyzes the diversity of working model on the backgroundof different time slot configurations in TDD system. Two working models areproposed for a diverse of scenarios, interference avoiding oriented scheduling is alsoconsidered. The result from simulation shows that D2D cooperative relaying systemcan improve the throughput.