Differential Modulation for Bidirectional Relaying With Analog Network Coding

Sch. of Electron. & Comput. Sci., Peking Univ., Beijing, China
IEEE Transactions on Signal Processing (Impact Factor: 2.79). 08/2010; 58(7):3933 - 3938. DOI: 10.1109/TSP.2010.2046441
Source: IEEE Xplore


In this correspondence, we propose an analog network coding scheme with differential modulation (ANC-DM) using amplify-and-forward protocol for bidirectional relay networks when neither the source nodes nor the relay knows the channel state information (CSI). The performance of the proposed ANC-DM scheme is analyzed and a simple asymptotic bit error rate (BER) expression is derived. The analytical results are verified through simulations. It is shown that the BER performance of the proposed differential scheme is about 3 dB away from that of the coherent detection scheme. To improve the system performance, the optimum power allocation between the sources and the relay is determined based on the simplified BER. Simulation results indicate that the proposed differential scheme with optimum power allocation yields 1-2 dB performance improvement over an equal power allocation scheme.

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    • "Hence, we propose to use differential modulation for two-way satellite communication for avoiding the need for the channel information in ES-i. Let x i [n] be a differentially modulated symbol transmitted by the ES-i, then we have the following relation: x i [n] = x i [n − 1]s i [n], (3) where s i [n] denotes the information containing symbol to be transmitted in the n-th time-interval; |x i [n]| 2 = 1 which denotes that s i [n] belogs to a unit-norm M -ary phase shift keying (M -PSK) constellation A. Since the satellite links do not follow the reciprocity, the existing decoders of the terrestrial differential two-way relaying [25] are not applicable for the differential twoway satellite relaying. Therefore, we need to develop new differential decoder for the proposed system. "
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    • "The beamforming design requires the channel state information (CSI) of the LR and/or the UR priori. The physical layer security can be used in many application senarios [5] [6] [7], e.g., the two-way relaying [11] [12] [13]. "
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    • "Unlike [8] "

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