在合作式自動重傳系統中使用嵌入可適性放大傳送/解碼傳送元素的分散式空時區塊碼

我們在合作式自動重傳系統中考慮了一個source，三個中繼站與一個目的端。每個節點都擁有一根天線。在之前的合作式系統中，中繼站到目的端的傳送方式有兩種，第一種是每次傳送都只用一個擁有正確資訊或是擁有最好通道的中繼站來傳送；第二種是每次傳送都用2個或2個以上的中繼站合作使用DSTBC傳送。第一種方法的缺點是，在中繼站到目的端間的傳送發生錯誤的機會比用兩個以上中繼站合作傳送來的高。而這兩種方法還有一個缺點是在中繼站裡都只用放大傳送(AAF)或是只用解碼傳送(DAF)，這在低SNR的時候效果不佳。在我們提出的方法中，我們會隨著情況來改變使用多少個中繼站合作將資訊傳送到目的端。換句話說，在我們提出的系統中中繼站到目的端間的傳送可能由一個或是一個以上的中繼站負責傳送而非固定一個或是多個中繼站負責。另外一個與之前研究不同的地方是，我們在中繼站裡使用嵌入式AAF/DAF的DSTBC元素而不是只使用AAF或是只使用DAF。最後，我們提出的方法在位元錯誤率10-6時比之前的方法好了3dB，中繼站與目的端間的重傳次數在SNR大於15dB時降低了超過50%。

關鍵字

合作式系統；機會性聆聽；分散式；分散式空時區塊碼；可適性；解碼傳送放大傳送

並列摘要

In the cooperative relaying auto repeat-request (ARQ) system, we consider the cooperative networks of one source, three relays, and one destination. All of them are equipped with single antenna. In the previous cooperative ARQ scheme, they using inter-relay opportunistic listening (OL) to improve the bit error rate (BER) performance, but they always use one relay to communication with the destination, and this may increase the retransmission times between relay and destination. Different from previous works, we set a threshold to make a selection. If most of the channel quality of source-relay channel is under the threshold, we use the same scheme as previous scheme. Otherwise, we pick two relays to communicate with destination using the proposed DSTBC matrix under different situation. When two relays are picked to transmit, there has no retransmission occur, and this may decrease the retransmission times. The proposed scheme is a DSTBC matrix with embedded adaptive DAF/AAF elements. If the result of cyclic redundancy check (CRC) is correct, we select the corresponding elements of the DSTBC matrix to be the decode and forward (DAF) type. Otherwise, we select the corresponding elements of the DSTBC matrix to be the amplify and forward (AAF) type. The simulation result shows that our proposed system has 3dB gain over the previous cooperative ARQ scheme at BER 10-6. And the retransmission times is reduced more than 50% than the previous cooperative ARQ scheme after SNR 15dB.

並列關鍵字

Cooperative system ； opportunistic listening ； distributed ； DSTBC ； adaptive ； DAF ； AAF

參考文獻

[1] G. Yu, Z. Zhang and P. Qiu, “Cooperative ARQ in wireless networks: protocols description and performance analysis,” in Proc. of IEEE ICC 2006, vol.8, pp.3608-3614, Istanbul, Turkey, June 2006.

[2] E. Beres, R. Adve, “Outage probability of selection cooperation in the low to medium SNR regime,” IEEE Commun. Letter, vol. 11, no. 7, pp. 589-591, July 2007.

[3] N. Lynn, O. Takyu, K. Adachi, M. Nakagawa, and T.Ohtsuki, ”Cooperative ARQ using distributed relay selection and inter-relay opportunistic listening,” in Proc IEEE PIMRC, pp. 467–472, Istanbul, Turkey, Sept. 2010.

[4] I.-H. Lee, “Outage performance of efficient partial relay selection in amplify-and-forward relaying systems over Rayleigh fading channels,” IEEE Commun. Lett., vol. 16, pp.1644-1647, Oct. 2012.

[5] B. Aggelos, K. Ashish, P. R David and L. Andrew, “A simple cooperative diversity method based on network path selection,” IEEE J. Select. Areas Commun, vol.24, no.3, pp.659-672, Mar. 2006.

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在合作式自動重傳系統中使用嵌入可適性放大傳送/解碼傳送元素的分散式空時區塊碼

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