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In this paper, cross-layer combining of an adaptive modulation-coding (AMC) scheme at the physical layer and the use of automatic repeat request (ARQ) retransmissions at the medium access control (MAC) layer is integrated into the design of scheduling for multi-user wireless networks. A class of scheduling algorithms capable of jointly collecting retransmission diversity and multi-user diversity are...
In this paper, we evaluate the impact of the wireless channel and physical layer parameters on the performance of VoIP traffic in IEEE 802.11g networks. The wireless channel is modeled using a finite state Markov chain based on an adaptive modulation and coding scheme. The transition probabilities encompass the effects of the time-varying wireless channel, such as the Doppler frequency and the operating...
In this paper, an energy efficient adaptive modulation scheme is proposed for a wireless cognitive radio ad hoc network, where each node is equipped with cognitive radio and the network is an OFDMA system operating on time slots. In each slot, the users with new traffic demand will sense the spectrum and locate the available subcarrier set. Then they choose subcarriers with favorable channel condition...
In this paper, we study bandwidth management of a wireless/optical based access/metro network in support of voice and data services. For voice services, we use a finite state Markov Chain to estimate the blocking probability of voice circuits over an Adaptive modulation and coding wireless channel, as a function of the channel parameters. For data services, we evaluate a rate matching and a buffer...
This paper considers the issue of delay optimal subcarrier allocation in OFDMA wireless networks when the arrivals and channels are stochastic. Our objective is to minimize the long-term average packet delay over multiple time epochs. In previous studies, we have shown that the optimal policy is complicated and unknown. However, based on the insights learned from a simple on-off channel model, we...
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