Variable packet splitting transmission in multi-relay cooperative communications with DF and DAF for SC-FDMA

Abstract

In recent years, cooperative communications are widely studied. Cooperative communications can obtain the space diversity as multiple-input multiple-output (MIMO) systems. In cooperative communications, the relay method is important as decode-and-forward (DF) and decode-amplify-forward (DAF). The multi-relay cooperative communications can improve the system performance. In the multi-relay cooperative communications, the optimum packet splitting method is effective. Moreover, the multi-relay cooperative communications can more improve the system performance by using the power allocation (PA). However, the PA method requires large feedback information (FBI). To solve this problem, in this article, we propose the optimum packet splitting method based on the time domain channel state information (CSI) in the multi-relay cooperative communication with DF and DAF.

Packet splitting and adaptive modulation based on CSI of time domain for decode‐and‐forward cooperative OFDM systems in different channel model

“…Here, we consider the channel condition for the frequency and time domains. As mentioned in Ida et al and Xiao et al, in the frequency domain, the channel condition is changed due to a multipath fading. In this case, the information of all subcarrier channels should be feedback to the source node.…”

“…This is because, in a small Doppler frequency case, the power for the CSI of the time domain is a constant . By using this characteristic, Ida et al can reduce the number of FBI from the number of subcarrier channels to one. Moreover, the adaptive modulation has been proposed to improve the transmission rate .…”

“…13,14 For the other method, the optimum channel selection and the packet splitting have been proposed. [15][16][17][18][19][20] By using the channel state information (CSI) of each link, previous studies [15][16][17][18][19][20] show the good system performance without the sending same signal from the different node. In other studies, [17][18][19] the packet splitting has been mentioned.…”

“…For the above problem, since the transmission rate can be improve by selecting a high modulation level, the low complex maximum likelihood decoder for DF cooperative communications has been proposed and has shown the good system performance by using several modulations . For the other method, the optimum channel selection and the packet splitting have been proposed . By using the channel state information (CSI) of each link, previous studies show the good system performance without the sending same signal from the different node.…”

Joint Adaptive Modulation and Transmit Power Control on FSS-OFDM Mobile Relay System

“…AF is that the relay node forwards the incoming signal only by amplifying in the analog domain, so that forwarding delay is relatively low while additive noise effect may be enhanced [4] [5]. In DF, the relay node once demodulates and decodes the source message and transmits the re-encoded message [6] [7]. Although DF incurs oppressed computation complexity and delay, it can provide better communication quality than AF.…”