An Adaptive-Transmission Cross-Layer Protocol with Selective MAC Layer Spatial Reuse Capabilities for Ad Hoc Networks

Abstract

This paper explores the interaction between medium access control (MAC) techniques such as selective node silencing with physical-layer adaptive techniques such as spreading adaptation for direct-sequence spread-spectrum packet radio networks. Because this type of network shares a spatial resource, interaction between adaptive mechanisms at each radio must be considered in concert to derive optimal system parameters and modes of operation. This paper explores how MAC techniques can be employed to enhance previously suggested adaptive physical layer techniques. We propose and evaluate a distributed-heuristic, cross-layer protocol to govern efficient use of spatial resources based on specific physical layer measurements. We compare our proposed protocol to standard protocol approaches for this type of network using various measures to test network performance. The benefits of protocols which integrate the MAC protocol with higher layers are also considered.