Experiments on IP Packet Transmission Performance for Real Time Traffic Data Employing Adaptive Modulation and Channel Coding in Forward Link for VSF-OFCDM Broadband Wireless Access

摘要

This paper presents experimental results on average IP packet loss rate (PLR) and code-channel utilization rate over Radio Access Network (RAN) employing Adaptive Modulation and channel Coding (AMC) and hybrid ARQ (Automatic Repeat request) with packet combining for real time (RT) traffic data with rigid delay requirement, in the forward link using 100-MHz bandwidth for VSF-OFCDM (Variable Spreading Factor-Orthogonal Frequency and Code Division Multiplexing) broadband wireless access. Experimental results elucidated that assuming the RT type IP packet traffic with information bit rate of 24 Mbps and the size of 1500 bytes, the code-channel utilization rate with AMC was reduced by approximately 15 % compared to that with QPSK modulation at the average received E{sub}s/N{sub}o below approximately 1dB, where the average PLR of below 10{sup}-3 was realized (L = 6-path Rayleigh fading channel with the fading maximum Doppler frequency of f{sub}D = 20 Hz). Moreover, it was clarified that as L became larger and f{sub}D became lower, the code-channel use rate was decreased.