本文首先提出了一种分析OFDMA蜂窝网络下行链路呼叫阻塞率的方法,在此基础上进一步分析了加入两跳中继的OFDMA蜂窝网络呼叫阻塞率.OFDMA蜂窝网络的每个呼叫接入都需要随机数量的子载波来满足用户传输速率的需求,传统GSM及CDMA网络的容量分析方法不能应用到OFDMA网络系统中.本文根据用户对子载波的需求量,把接入用户分成不同的服务类型,以多维马尔可夫链为数学模型分别分析传统和两跳中继OFDMA蜂窝网络下行链路呼叫阻塞率,最终通过数值计算分析各种参数对系统性能的影响,数值分析结果表明加入中继后的两跳中继OFDMA蜂窝网络下行链路容量比传统网络有显著的提升.
In this paper,a novel approach is presented to evaluate the call blocking probability in downlink of cellular Orthogonal Frequency Division Multiple Access( OFDMA) networks. Based on this analysis,call blocking probability in downlink of two-hop-relay OFDMA cellular networks is evaluated. Capacity analysis of traditional cellular networks like GSMand CDMA cellular networks cannot be applied to OFDMA cellular networks because for the latter every incoming call requires a random number of sub-carriers. In this paper,incoming calls are divided into classes according to their requirement for sub-carrier. Then,the traditional and relay OFDMA cellular network are modeled as the multi-dimensional Markov chain and their call blocking probability in downlink are evaluated. Finally,through numerical calculation,the impact of the various parameters on the performance is analyzed. This analysis shows that the capacity of OFDMA cellular networks which added relays has been greatly improved.