Managing Interference Correlation Through Random Medium Access

• Published in: IEEE transactions on wireless communications Vol. 13; no. 2; pp. 928 - 941
• Main Authors: Yi Zhong, Wenyi Zhang, Haenggi, Martin
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.02.2014; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Access methods and protocols, osi model; ALOHA; Applied sciences; Correlation; Delay; Delays; Exact sciences and technology; Exact solutions; Fading; frequency-hopping; Interference; interference correlation; local delay; Mathematical analysis; Multiple access; Optimization; Poisson point process; Receivers; stochastic geometry; Switching and signalling; Systems design; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Teleprocessing networks. Isdn; Time-frequency analysis; Transmission and modulation (techniques and equipments); Transmitters; Wireless networks; Access control; Timing jitter; Multiple access; Packet switching; Tail probability; Wireless telecommunication; interference correlation; local delay; System design; ALOHA; stochastic geometry; Poisson process; Frequency hop communication; Poisson point process; Point process; frequency-hopping; Random access; Wireless network; Delay time; Access protocol; Random medium; Multiple frequency
• ISSN: 1536-1276; 1558-2248
• DOI: 10.1109/TWC.2013.122313.131613

The capacity of wireless networks is fundamentally limited by interference. However, little research has focused on the interference correlation, which may greatly increase the local delay (namely the number of time slots required for a node to successfully transmit a packet). This paper focuses on the question whether increasing randomness in the MAC, specifically frequency-hopping multiple access (FHMA) and ALOHA, helps to reduce the effect of interference correlation. We derive closed-form results for the mean and variance of the local delay for the two MAC protocols and evaluate the optimal parameters that minimize the mean local delay. Based on the optimal parameters, we identify two operating regimes, the correlation-limited regime and the bandwidth-limited regime. Our results reveal that while the mean local delays for FHMA with N sub-bands and for ALOHA with transmit probability p essentially coincide when p=1/N, a fundamental discrepancy exists between their variances. We also discuss implications from the analysis, including an interesting mean delay-jitter tradeoff, and convenient bounds on the tail probability of the local delay, which shed useful insights into system design.