γ-TBSC: Time-Bound Signaling Control with γ-Percent Soft Guarantee in IEEE 802.11 Wireless LANs

Signaling control schemes for wireless multimedia services are expected to maximize the number of newly-accepted mobile terminals (MTs), i.e., system throughput, while maintaining the quality of service (QoS) requirements for the existing MTs in the system. In this paper, we propose a gamma-percent time-bound signaling control (gamma-TBSC) scheme that resolves a maximum number of MTs mostly within a given bounded time, subject to assuring gamma-percent soft guarantee for existing MTs. The gamma-TBSC scheme performs signaling control in two phases: the call-invitation phase, and the contention-resolution phase. In the first phase, an access point invites a number of so-called potential MTs to make reservations during a call invitation interval (CII). If any collision occurs, gamma-TBSC performs contention resolution in the second phase until all potential MTs are resolved successfully. Most importantly, prior to the two-phase operation, gamma-TBSC analytically and statistically determines the potential MT number and the CII length such that the system throughput is maximized and the QoS is soft guaranteed. From simulation results that pit gamma-TBSC against several variants of carrier sense multiple access with collision avoidance (CSMA/CA) schemes, we delineate that gamma-TBSC outperforms these schemes with respect to throughput and delay performance.