Resource allocation for user-relay assisted MISO-OFDMA networks

Abstract

Abstract-The next generation cellular networks request higher capacity and coverage that user-relay assisted Orthogonal Frequency Division Multiple Access (OFDMA) networks are cost effective solutions to meet these demands. These networks can be enriched with multiple antennas in order to obtain a diversity gain to combat signal fading and to achieve more capacity gain without increasing the bandwidth or transmit power. However, radio resource management (RRM) such as relay selection and resource allocation (RA) is important in such a multi-user, multi relay and multi-antenna environment to fully take advantage of multiple-input single-output (MISO)-OFDMA based user-relay assisted cellular networks. Thus, we propose a RA algorithm for these networks to reveal the benefits of the combination of user relaying and multiple antennas technologies and compare the proposed scheme with existing schemes in terms of percentage of satisfied users and cell-edge users' data rate.

User-relay assisted cellular networks with multiple antennas

“…In Shim et al (2010), uplink OFDMA-based wireless network is considered and subcarrier-power allocation algorithms are presented by taking care of the fairness constraint. In Basturk and Ozbek (2015), the classical two-phase frame structure is used with multiple antennas and the RA is performed on MISO-OFDMA-based cellular networks. In Basturk and Ozbek (2016a), a novel three-phase frame structure in which the users are not allowed to act as a destination and a relay simultaneously is developed since the assumption in which users are able to transmit and receive at the same time through adjacent subcarriers may have practical limitations with the current transceiver design.…”

“…• The proposed scheme has multifold advantages that multiuser diversity can be exploited not only in the frequency domain, but also in the spatial domain contrary to works (Basturk & Ozbek, 2016a, 2016b in which SISO scheme is used. Moreover, users are prevented to act as a destination and a relay simultaneously contrary to (Basturk & Ozbek, 2015;Ng & Yu, 2007;Weng & Murch, 2009) since only the satisfied users are assigned as the user-relay candidates. Thus, it is more practical with the current transceiver design.…”

Channel and queue aware joint relay selection and resource allocation for MISO-OFDMA based user-relay assisted cellular networks

“…Thus, it is necessary to develop efficient RRM algorithms such as relay selection and resource allocation in order to reveal the advantages of these combined technologies. There are many works studied on the RRM problem for OFDMA-based fixed relay networks [17][18][19][20][21][22][23][24][25][26] and mobile relay networks [27][28][29][30][31][32][33][34][35][36]. These works use the common assumption that users have infinitely backlogged buffers in BS.…”

“…• A novel channel and queue aware sub-optimum joint relay selection and resource allocation algorithm is proposed to solve the formulated RRM optimization problem since the existing queue-aware algorithms presented for SISO-OFDMA systems [40][41][42][43][44] can not be directly applied to the MISO-OFDMA systems in which more than one user is supported per subchannel. • The proposed algorithm is suitable for the realistic scenarios and use system resources efficiently because of the queue-awareness contrary to [27][28][29][30][31][32][33][34][35][36] where queue information is ignored with the assumption that users have infinitely backlogged buffers in BS. • Relay selection and resource allocation is performed jointly in the proposed scheme contrary to many works in the literature [19,34,42], since separated relay selection and resource allocation can limit the system performance.…”

“…• Relay selection and resource allocation is performed jointly in the proposed scheme contrary to many works in the literature [19,34,42], since separated relay selection and resource allocation can limit the system performance. • In most of the existing works in the literature, it is assumed that the same subchannel is used for the BS to relay and for the relay to users links at different time slots [27,29,[34][35][36]. However, the performance of the system is limited due to this assumption, despite the fact that the complexity of the problem is reduced.…”