Performance Bounds for Bidirectional Coded Cooperation Protocols
Performance Bounds for Bidirectional Coded Cooperation Protocols
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DOI：
10.1109/tit.2008.929913
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发表时间：
2008-11
影响因子：
2.5
通讯作者：
Sang Joon Kim;P. Mitran;V. Tarokh
中科院分区：
文献类型：
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作者：
Sang Joon Kim;P. Mitran;V. Tarokh
在编码双向协作中，两个节点希望在中继的帮助下通过共享的半双工信道交换消息。在本文中，我们针对三种解码转发协议中的每一种推导了该问题的性能界限。第一种协议是一个两阶段协议，在第一阶段两个用户同时传输，在第二阶段仅中继传输。对于该协议，我们的界限是紧的。第二种协议考虑两个用户依次传输，然后中继传输，而第三种协议是前两种协议的混合，有四个阶段。在后两种协议中，界限并不相同。数值评估表明，在一些我们感兴趣的情况下，我们的界限差异不大。最后，在具有路径损耗的高斯情况下，我们推导了可实现的速率，并比较了每种协议的相对优劣。这种情况在蜂窝系统中是有意义的。令人惊讶的是，我们发现，在某些情况下，四阶段协议的可实现速率区域包含位于其他两种协议外边界之外的点。
In coded bidirectional cooperation, two nodes wish to exchange messages over a shared half-duplex channel with the help of a relay. In this correspondence, we derive performance bounds for this problem for each of three decode-and-forward protocols. The first protocol is a two phase protocol where both users simultaneously transmit during the first phase and the relay alone transmits during the second. In this protocol, our bounds are tight. The second protocol considers sequential transmissions from the two users followed by a transmission from the relay while the third protocol is a hybrid of the first two protocols and has four phases. In the latter two protocols the bounds are not identical. Numerical evaluation shows that in some cases of interest our bounds do not differ significantly. Finally, in the Gaussian case with path loss, we derive achievable rates and compare the relative merits of each protocol. This case is of interest in cellular systems. Surprisingly, we find that in some cases, the achievable rate region of the four phase protocol contains points that are outside the outer bounds of the other two protocols.