Bandwidth allocation in wireless networks with guaranteed packet-loss performance

Abstract

Providing quality-of-service (QoS) guarantees over wireless packet networks poses a host of technical challenges that are not present in wireline networks. One of the key issues is how to account for the characteristics of the time-varying wireless channel and for the impact of link-layer error control in the provisioning of packet-level QoS. We accommodate both aspects in analyzing the packet-loss performance over a wireless link. We consider the cases of a single and multiplexed traffic streams. The link capacity fluctuates according to a fluid version of Gilbert-Elliott channel model. Traffic sources are modeled as on-off fluid processes. For the single-stream case, we derive the exact packet-loss rate (PLR) due to buffer overflow at the sender side of the wireless link. We also obtain a closed-form approximation for the corresponding wireless effective bandwidth. In the case of multiplexed streams, we obtain a good approximation for the PLR using the Chernoff-dominant eigenvalue (CDE) approach. Our analysis is then used to study the optimal forward error correction code rate that guarantees a given PLR while minimizing the allocated bandwidth. Numerical results and simulations are used to verify the adequacy of our analysis and to study the impact of error control on the allocation of bandwidth for guaranteed packet-loss performance.