The ergodic information rate for Orthogonal Frequency-Division Multiplexing / Orthogonal Frequency-Division Multiple Access with amplify-and-forward （AF） relaying systems in the presence of frequency offsets is eval...The ergodic information rate for Orthogonal Frequency-Division Multiplexing / Orthogonal Frequency-Division Multiple Access with amplify-and-forward （AF） relaying systems in the presence of frequency offsets is evaluated. Unlike previous work, per-subcarrier adaptive power allocation is performed on each relay to optimize the system ergodic information rate. For a given frequency offset and total number of relays M, the AF ergodic information rate is proven to be a monotonically increasing function of α （the ratio of the power allocated to the source node and the total transmit power）, implying that the maximum ergodic information rate can be obtained at α=1 （i.e., there is no cooperative relay）. Furthermore, the proof of ＂cooperative relays cannot improve the AF ergodic information rate in a quasi-static wireless channel＂ is also provided in this letter.展开更多
基金the 863 project No.2014AA01A701,the National Natural Science Foundation of China，Program for New Century Excellent Talents in University，the open research fund of National Mobile Communications Research Laboratory Southeast University，the Research Foundation of China Mobile,and the Foundation of Beijing Engineering and Technology Center for Convergence Networks and Ubiquitous Services
文摘The ergodic information rate for Orthogonal Frequency-Division Multiplexing / Orthogonal Frequency-Division Multiple Access with amplify-and-forward （AF） relaying systems in the presence of frequency offsets is evaluated. Unlike previous work, per-subcarrier adaptive power allocation is performed on each relay to optimize the system ergodic information rate. For a given frequency offset and total number of relays M, the AF ergodic information rate is proven to be a monotonically increasing function of α （the ratio of the power allocated to the source node and the total transmit power）, implying that the maximum ergodic information rate can be obtained at α=1 （i.e., there is no cooperative relay）. Furthermore, the proof of ＂cooperative relays cannot improve the AF ergodic information rate in a quasi-static wireless channel＂ is also provided in this letter.
