Decoding techniques for alternate-relaying BICM cooperative systems

Abstract

In this paper, we propose the use of bit-interleaved coded modulation in alternate-relaying decode-and-forward cooperative communication systems. At the destination, we exploit the interference signal, which results from the simultaneous transmission of data streams through both direct and one of the relay channels to develop an optimal detector. It is shown that the proposed detector can be implemented by parallel concatenating maximum a posteriori (MAP) algorithms and demappers to the decoders. The detector exchanges soft information between the decoders and the MAP algorithms in an iterative way for performance improvement. The proposed optimal detector requires a long delay as the destination has to receive and store the entire frame before performing data detection. To avoid this, a sub-optimal detector is also proposed. Unlike the optimal detector, the sub-optimal one exploits two consecutive received packets to decode one packet. It turns out that the sub-optimal detector has less reduced delay, complexity, memory size, and bandwidth loss with a slight increase of the bit-error-rate. Extensive simulation results are presented to demonstrate the effectiveness of the proposed detectors.

Data Detection Algorithms for BICM Alternate-Relaying Cooperative Systems With Multiple-Antenna Destination

“…This leads to a performance close to the case of perfect interference cancellation at the relays [1], [4]. It is worthy to mention that in our previous work [8], we proposed a data detection technique at the two relays. This detector can be used over a wide range of distance between the two relays.…”

“…Using the fact that the diversity order is defined as the limit of log(BER)/log(SNR) when the signal-to-noise (SNR) value tends to infinity, it is clear that deriving a general expression for the diversity order of BICM-ID systems is a very challenging task. 6 Simulation results, not shown here due to the space limitation, indicate that a similar BER performance at the destination supporting two antennas is obtained with a loss of SNR by about 0.5 dB in the case of non-ideal interference cancellation at the relays with σ 2 R 1 R 2 = 1.6 and employing the detection algorithm at the relays proposed in [8]. Note that the value of σ 2 R 1 R 2 does not be considered in the previous simulation results, because we followed the assumption of [1], [4] that the two relays are selected such that their link is negligible when compared with both S − R 1 and S − R 2 links.…”

“…We consider an ARC system, using a convolutional code with a coding rate of 1/2, constraint length of 5, and polynomial generators given by (23) 8 and (35) 8 . The BCJR algorithm [13] is used for decoding.…”

“…It is worthy to mention that the data detection problem of bit interleaved coded modulation (BICM) ARC system is investigated for single-antenna nodes in[8]. This problem is also considered for uncoded transmission with a single-antenna nodes in[7] and multiple-antenna destination in[9].…”

Multiuser Detection Schemes for Multicarrier Four-node Wireless Systems

“…Generally speaking, the previous work on TPC can be categorized into two groups of studies. A group has concentrated on the information theory issues such as capacity-outage and diversity-multiplexing tradeoff analysis ( [1,4]) while the second one is devoted to data detection algorithms [2,3,6]. The previously mentioned works of the second group were considered a single user with single carrier transmission.…”