Link adaptation algorithms for improved delivery of delay- and error-sensitive packet-data services over wireless networks

Abstract

Link Adaptation is a radio resource management technique that assesses the channel conditions and selects a transport mode, from a set of possible options, which is optimised for these conditions according to a predefined criterion. The optimum transport mode is commonly determined so as to maximise the throughput. Although this approach may be appropriate for best-effort services, its suitability for multimedia services, usually characterised by tight delay and error performance constraints, has been questioned. As a result, a number of alternative algorithms have been proposed in the literature. In this context, this paper presents and evaluates in a dynamic radio environment several Link Adaptation algorithms designed to enhance the provision of delay-and error-sensitive multimedia packet-data services over wireless systems. The obtained results demonstrate that significant improvements in terms of throughput, transmission delay, error performance and operation of Link Adaptation itself can be obtained with the proposed schemes.

Common Radio Resource Management Algorithms for Multimedia Heterogeneous Wireless Networks

“…various combinations of transmission parameters such as modulation and coding scheme, that provide different trade-offs between resilience to propagation errors and transmission rates. In this case, the TM employed is usually changed dynamically according to the experienced instantaneous channel quality following different Link Adaptation (LA) or Adaptive Modulation and Coding (AMC) techniques [12], [13]. Considering these adaptive policies, the throughput, and hence the utility for each RAT, can be estimated using the BLock Error Rate (BLER) for each TM as a function of the channel quality.…”