摘要： 對D2D（Device to Device）通信系統(tǒng)的容量擴展問題進行了研究，提出了一種雙向中繼輔助的D2D通信系統(tǒng)，該系統(tǒng)采用非正交多址接入（Non-Orthogonal Multiple Access，NOMA）。首先分析了各信號的信干噪比（SINR），接著詳細計算了每個信號的累積分布函數(shù)（Cumulative Distribution Function，CDF）和概率密度函數(shù)（Probability Density Function，PDF），并據(jù)此推導(dǎo)出了系統(tǒng)遍歷總?cè)萘康慕庑问健３酥?，還分析了OMA系統(tǒng)的遍歷總?cè)萘?，與NOMA系統(tǒng)進行對比。仿真結(jié)果表明，NOMA系統(tǒng)的可達速率優(yōu)于OMA系統(tǒng)，雙向中繼能夠比傳統(tǒng)的單向中繼獲得更高的容量。
(1.College of Telecommunications＆ Information Engineering，Nanjing University of Posts and Telecommunications，Nanjing 210003，China；2.Key Lab of Broadband Wireless Communication and Sensor Network Technology，Ministry of Education，Nanjing University of Posts and Telecommunications，Nanjing 210003，China)
Abstract： A two-way relay-assisted device to device (D2D) communication system using non-orthogonal multiple access (NOMA) is proposed to solve the capacity scaling for D2D communication system. Firstly, the signal to interference noise ratio (SINR) of each signal is analyzed, and according to the cumulative distribution function (CDF) and probability density function (PDF) of each signal, the solution form of the ergodic sum capacity of the system is obtained. In addition, the ergodic sum capacity of orthogonal multiple access (OMA) system is analyzed and compared with NOMA system. Simulation results show that compared with OMA system, the achievable capacity of the system can be improved when NOMA is used, and the two-way relay scheme can make the system obtain higher capacity than the traditional one-way relay scheme.
Key words : device to device （D2D）；non-orthogonal multiple access （NOMA）；two-way relay；ergodic sum capacity
