Improving methods of ICMA/CD protocol in packet mobile radio networks and their performance analysis

Abstract

There have been a great deal of interests in packet mobile radio networks but CSMA/CD protocols used in fixed-terminal radio communication or LAN is not adaptable practically. A centrally-controlled multiple access scheme, known as idle-signal casting multiple access with collison detection (ICMA/CD), was proposed to solve this problem. The performance of ICMA/CD protocols is greatly affected by the packet detection dealy which is generally large tnan that of drdinary LAN or fixed-terminal radio communications. Our improving methods are baaed on a reduction of the large packet detection delay``s and a regulation of traffic load in accordance to channal state histories. Novel channel access scheme (ICMA/CD-R) is introduced to avoid collisions during the packet detection delay and another channel access shceme (VT-ICMA/CD) is adapted for a regulation of traffic load by exploiting the virtual-time protocol concept. Above two channel access algorithms can be used independently for reducing packet failure probability and enhancing the channel capacity. Finally, a combined algorithm (VT-ICMA/CD-R) of above two algorithms is proposed to produce a more improved performance by taking advantage of the merits of ICMA/CDR and VT-ICMA/CD. These algorithms are analyzed in terms of channel capacity, packet failure probability (PFP), average number of reschedulings (ANR), packect dealy and channel stability, compared to existing ICMA/CD protocls. The copmparisons show that proposed algorithms are superior to those of the existing algorithms in above-mentioned performace measures and are less affected by the packet detection delay. The ICMA/CD protocols can be sued for real-time applications such as mobile a lower average rescheduling number, a lower packet delay and a better stability more approximates the first-come-first-service(FCFS) rule. These properities are especially for mobile phone system where voice packets are to be transmitted without being descarded and in the or...