A Novel Architecture for Multi-Hop WiMAX Systems: Shared Relay Segmentation

The requirements of IMT-Advanced [1] dictate innovations in radio resource management, including cross-layer optimization of radio resource allocation, inter-cell coordination, and interference mitigation strategies, dynamic and aggressive resource reuse, as well as state-of-the-art spatial signal processing. All of these technologies must be supported by an advanced radio access network capable of exploiting each ideally to their fullest extent. This paper proposes a novel radio access network architecture that we refer to as Shared Relay Segmentation (SRS) cellular architecture. While the concept of SRS may be implemented in a generic cellular multi-hop network, we focus on attributes of the SRS cell architecture that make it attractive for adoption in 4G networks such as WiMAX [2,3,4]. There are three main contributions in this work: We describe a novel and applique multi-hop cellular architecture requiring on average a single shared infrastructure relay station per WiMAX sector. We develop a multi-hop fractional frequency reuse strategy derived from the WiMAX segmentation plan [5]. We develop an optimal centralized radio resource allocation scheme, based on the Hungarian algorithm [6], enabling adaptive non-transparent cooperative relaying in the downlink access zone of a WiMAX sector. We demonstrate through system simulations how an SRS WiMAX cellular architecture improves both sector coverage and capacity over conventional WiMAX systems. We use system parameters and performance metrics defined for evaluation of IEEE 802.16j/m systems as reference [7,8]. Furthermore, we speculate that the SRS cellular architecture is suitable for applique enhancement of existing WiMAX deployments, enabling incremental CAPEX expenditure by network operators where driven by service demand.