Integrated Radio Resource Allocation for Multihop Cellular Networks With Fixed Relay Stations

Abstract

Abstract-Recently, the notion that a logical next step towards future mobile radio networks is to introduce multihop relaying into cellular networks, has gained wide acceptance. Nevertheless, due to the inherent drawbacks of multihop relaying, e.g., the requirement for extra radio resources for relaying hops, and the sensitivity to the quality of relaying routes, multihop cellular networks (MCNs) require a well-designed radio resource allocation strategy in order to secure performance gains. In this paper, the optimal radio resource allocation problem in MCNs, with the objective of throughput maximization, is formulated mathematically and proven to be NP-hard. Considering the prohibitive complexity of finding the optimal solution for such an NP-hard problem, we propose an efficient heuristic algorithm, named integrated radio resource allocation (IRRA), to find suboptimal solutions. The IRRA is featured as a low-complexity algorithm that involves not only base station (BS) resource scheduling, but also routing and relay station (RS) load balancing. Specifically, a load-based scheme is developed for routing. A mode-aware BS resource-scheduling scheme is proposed for handling links in different transmission modes, i.e., direct or multihop. Moreover, a priority-based RS load balancing approach is presented for the prevention of the overloading of RSs. Within the framework of the IRRA, the above three functions operate periodically with coordinated interactions. To prove the effectiveness of the proposed IRRA algorithm, a case study was carried out based on enhanced uplink UMTS terrestrial radio access/frequency-division duplex with fixed RSs. The IRRA is evaluated through system level simulations, and compared with two other cases: 1) nonrelaying and 2) relaying with a benchmark approach. The results show that the proposed algorithm can ensure significant gains in terms of cell throughput.Index Terms-Cellular networks, fixed relay stations (RSs), multihop, radio resource allocation (RRA).

Resource allocation in relay enhanced LTE-Advanced networks

“…The problem of such resource partitioning in an REN was considered as early as 2005 in [8]. However, the type of segregation between the backhaul link and the access link considered in this study is fundamentally different from the current assumptions in the LTE-Advanced standard.…”

“…But their work also does not consider resource partition between the direct link and the backhaul link. Moreover, none of the above cited work [8][9][10][11][12][13][14] considers QoS support for users while designing the resource allocation schemes.…”

Channel Assignment in Multihop Cellular Networks

“…For example, a DIP is able to authorize a MS to relay the traffic for another MS. Different from ARSs in iCAR (Wu et al, 2001) or wireless ports in (Kudoh & Adachi, 2005) and (Liu et al, 2006), DIPs are not involved in data relaying. Hence, no worry about the capacity saturation problem, such as the load balancing considered in (Liu et al, 2006) for RSs, is concerned.…”

“…Different from ARSs in iCAR (Wu et al, 2001) or wireless ports in (Kudoh & Adachi, 2005) and (Liu et al, 2006), DIPs are not involved in data relaying. Hence, no worry about the capacity saturation problem, such as the load balancing considered in (Liu et al, 2006) for RSs, is concerned. Earlier researches have established that as long as there is a large number of MSs in the service area, it is not difficult for a DIP to find a RS.…”

Bandwidth and routing optimization in wireless cellular networks with relays

“…On a network level, load balancing, quality-of-service and proportional fairness considerations have been given in [12], [13] and [14], respectively. A central technique emerging from many of these network optimization studies is the idea of dual decomposition.…”