Smart cooperative relay schemes in LTE-advanced system. By Saransh Malik, Dahee No, Dae Jin Kim, Sangmi Moon, Se Young Kim, Intae Hwang, Bora Kim & Jin Lee
In ICUIMC 2012. Proceedings of the 6th International Conference on Ubiquitous Information Management and Communication (Kuala Lumpur, Malaysia, February 20, 2012), ACM, New York, NY, 2012, 1 -7.
CR Rev. No. 140276
A core problem of wireless data communication is how to maximize coverage while minimizing the bit error rate. To address this, the 4G technology known as long-term evolution-advanced (LTE-A) features a cooperative relaying scheme in which relay stations forward signals from neighboring mobile stations to the base station. When the base station receives the original signal together with the duplicated signal, it can restore bits more reliably than with the original signal alone.
This paper analyzes various cooperating relaying schemes, notably amplify-and-forward (AF), where the relay station forwards an amplified copy of the analog signal, and decode-and-forward (DF), where the base station decodes the signal, re-encodes the data, and sends a new signal. While DF does not amplify the noise (unlike AF), it does halve the bandwidth, so it should offer a better error rate. The protocol variants were analyzed under two linear equalization techniques, and under a diversity scheme where stations have multiple simultaneously operating antennas.
The majority of the paper is dedicated to an explanation of the various schemes. The new information contributed by the authors comes in the final section, where a simulation shows that, under the same constraints on transmission power, both relay schemes indeed represent an improvement in terms of error rate; DF clearly outperforms AF in all scenarios; and in the diversity scheme, AF with two antennas is better than DF with one antenna. While not groundbreaking news, these are solid results that confirm that the application of DF in LTE-A is well justified.
Reviewer: Wolfgang Schreiner (Linz, Austria)
[This review is a previously published Editor's Pick.]
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