Sum-rate optimized power allocation for the OFDM multiple access relay channel
Sum-rate optimized power allocation for the OFDM multiple access relay channel
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OFDM 多址中继信道的总速率优化功率分配
DOI：
10.1109/isccsp.2010.5463433
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
L. Vandendorpe
中科院分区：
文献类型：
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作者：
M. El Soussi;A. Zaidi;J. Louveaux;L. Vandendorpe
我们考虑基于 OFDM（正交频分复用）调制通过一组并行 MARC（多址中继信道）进行传输。两个用户在中继 (R) 的帮助下通过一组并行通道与共同目的地 (D) 进行通信。中继以解码和转发（重复编码类型）和半双工模式运行。所考虑的问题是通过将功率最优分配给用户和中继的不同载波来最大化目的地处的总速率。研究了总功率约束问题。我们表明，对于每个运营商，最多只能中继一个用户，而另一个用户应该通过直接链路进行通信。与经典 MAC 不同，我们表明存在两个用户应共享同一载波来传输符号的情况，这会提高速率。对于这些载体，考虑到中继和目的地，存在四种可能的解码顺序。由于问题是非凸和非线性的，因此先验地选择最佳解码顺序（在中继和目的地）以及应该中继哪个用户并不容易。提出了一种算法来解决全局优化问题。理论结果通过计算结果来说明。
We1 consider transmission over a set of parallel MARCs (multiple-access relay channel) based on the OFDM (Orthogonal Frequency Division Multiplexing) modulation. Two users communicate to a common destination (D) with the help of a relay (R) over a set of parallel channels. The relay operates in decode and forward (repetition coding type) and half duplex modes. The problem considered is the maximization of the total sum rate at the destination by optimal allocation of the power to the different carriers for the users and the relay. The problem is investigated for a sum power constraint. We show that for each carrier only one user should be relayed at most, and the other user should communicate over the direct link. Unlike the classical MAC, we show that there exist cases where both users should share the same carrier to transmit symbols and this increases the rate. For these carriers, there exist, considering both the relay and the destination, four possible decoding orders. As the problem is non-convex and non-linear, it is not easy to a-priori select the best decoding order (at the relay and the destination), and which user should be relayed. An algorithm is proposed to solve the global optimization problem. The theoretical results are illustrated by computational results.