Resource Allocation for Dynamic Intra-Cell Subcarrier Reuse in Cooperative OFDMA Wireless Networks

Abstract

Resource reuse schemes in relay-enhanced cooperative orthogonal frequency-division multiple access (OFDMA) networks have been well studied in the literature from an interference mitigation perspective and with cell-partitioning being the basis. In this paper however, we study dynamic intra-cell subcarrier reuse in cooperative OFDMA networks in which the users are allowed to share any subcarrier in the relay links provided that the resultant intra-cell interference is managed; an option not available in non-cooperative networks. Specifically, when the target data-rates of the users are not reachable in a conventional cooperative OFDMA network, dynamic intra-cell subcarrier reuse enables the users to achieve their target data-rates, even when the number of users surpasses the number of subcarriers. We formally define the problem of maximizing the system sum-rate subject to per node power and target data-rate constraints in a cooperative OFDMA single-cell network in which subcarriers are allowed to be reused in the relay links. After analyzing the problem in the dual domain and deriving the performance bounds, we propose a suboptimal resource allocation algorithm where subcarriers and links (relay and/or direct) are assigned to the users. Simulation results show that by employing our resource allocation algorithm, the system sum-rate and the outage ratio are significantly improved, specially in an overpopulated network.

High‐reliability and low‐complexity resource allocation for future multicarrier spread spectrum systems

“…However, in multicell multicarrier systems, severe intercell interference (InterCI) imposes a big challenge to resource management, where the interplay between InterCI and resource allocation should be addressed. In recent years, resource allocation in multicell multicarrier systems has drawn intensive research attention, as evidenced, eg, by the other works [7][8][9][10][11][12][13][14] and references there in. In the literature, related works 7-10 have investigated the centralized resource allocation in the multicell multicarrier systems.…”

“…The constraints (7) and (9) require that, in each cell, one subcarrier is assigned to N different users, and each user is allocated one subcarrier. For code allocation, (8) and (10) impose the constraints that, in each cell, a user is assigned one code, and a code is allocated to M different users. Note that, in the aforementioned equations,  denotes the set of code indexes.…”

“…In recent years, resource allocation in multicell multicarrier systems has drawn intensive research attention, as evidenced, eg, by the other works and references there in. In the literature, related works have investigated the centralized resource allocation in the multicell multicarrier systems. For example, Wang and Vandendorpe and Venturino et al proposed the centralized approach by assuming base station (BS) cooperation.…”

Distributed Resource Allocation Assisted by Intercell Interference Mitigation in Downlink Multicell MC DS-CDMA Systems

“…k , given by (7), is the achievable rate of user k in cell u. In (6), S (u) = {s k,n = 0. In above equations, N contains the indexes of codes in the system.…”

“…Resource allocation in multicell multicarrier systems can be categorized into two classes, namely centralized and distributed approaches. Specifically, centralized resource allocation has been widely investigated and studied in multicell scenarios, such as [5,6]. Despite exploiting various degrees of freedom in terms of allocation, centralized approach usually demands a very high implementation complexity and backhaul resources.…”