Multiuser diversity refers to the inherent diversity in channel quality across several mobile users in a wireless communication network. Multiuser diversity can be exploited through rate adaptation to increase system goodput, however the overhead incurred in polling channel state information in large networks can overshadow the multiuser diversity gain. In this paper, we propose a novel wireless medium access control protocol, multiuser diversity with capture (MDC), that uses the capture effect to avoid the large overhead incurred in polling channel state information. We simulate the goodput performance of MDC and compare it with the medium access diversity (MAD) scheme in the literature. Our results show that the proposed MDC outperforms MAD when the number of mobile stations in the network is reasonably large.

In ATM networks, one effective way to provide service guarantees is to shape individual traffic streams at various points in the network. In the paper, the authors present a method for multiplexing a large number of single-stream spacer outputs on cell emissions rather than on cell arrivals. The method not only approximates first come first served (FCFS) multiplexing of such outputs but also better suits bursty arrivals. A number of performance related issues of the proposed method are identified and examined.

Traffic shaping is important in ATM networks, especially those that are interconnected or provide service guarantees. We examine what shaping may be considered ideal, and what is attainable under the constraints of transmission systems and cost. We justify the use of FCFS multiplexing of multiple single-stream shaper outputs as a performance reference for multi-stream shapers, but also point out some of its deficiencies. Shaper implementations in which transmissions are scheduled on cell arrivals, emissions, and transmissions are examined and compared both qualitatively and through simulation. We identify the problem of shaping cells that must conform to multiple traffic constraints (e.g. when the rate of a multicast connection must be adapted to suit multiple links) and examine implementations to achieve this. Shaping in which inevitable cell delay variation is intentionally distributed inequitably amongst connections (to assist CDV-intolerant connections) is also examined.>

The authors examine how to provide constant bit rate (CBR) service over a channel that can be characterized by a constant transmission delay plus a variable cell access delay. To compensate for the variability in the access delay, buffers are used at the source and the destination ends of the connection. Whenever buffers overflow or underflow the continuity of data flow over the connection breaks down. The minimum size of buffers required at the transmitter and the receiver to provide the connection is determined. The minimum source to sink delay achievable for different buffer initialization strategies and the corresponding buffer prefills are derived.>

A method for supporting time-constrained and nontime-constrained integrated services on a shared dual bus network is presented. The method is an extension of the basic distributed queue protocol defined in the IEEE 802.6 distributed-queue dual-bus (DQDB) MAN standard. The extended distributed queueing protocol differs from the basic protocol in allowing more than one outstanding request in the distributed queue at any one time. Used at the high priority and in conjunction with segment stream shaping and subscribed service limiting, the extended protocol provides bearer services with guaranteed bandwidth and bounded delays. Bearer services with fair but nonguaranteed bandwidth shares, suitable for nontime-constrained applications, are provided by the same protocol and bandwidth balancing operating at the lowest priority. A number of the desirable attributes of the proposed scheme are identified including the optimality of the delay variance introduced by the access protocol. An approximate analysis of the access delay experience by time-constrained streams is presented.>

A generic flow control (GFC) protocol is proposed to regulate multiple terminals within the broadband-ISDN customer premises network. The GFC protocol is based on multipriority distributed queuing preceded by a traffic shaping function, and meets the requirements for flexible allocation of service parameters, control of jitter and guarantee of bandwidth. This GFC protocol provides the necessary flexibility to match the constant bit rate (CBR) jitter performance and variable bit rate (VBR) service requirements to the particular service type. It integrates well with usage parameter control without imposing excessive burstiness on each virtual connection cell stream delivered to the network. By allowing connectionless users to access at the lowest priority, only when no higher priority users are queued, there is no reduction in guaranteed capacity available for other VBR and CBR users.>