Radio resource management for user-relay assisted OFDMA-based wireless networks

Abstract

a b s t r a c tOrthogonal frequency division multiple access (OFDMA) based relay assisted networks are important for current and next-generation wireless networks since they have great potential to provide high data rate to users at anywhere, anytime. Towards that end, fixed relay assisted OFDMA networks are commonly utilized by the operators. However, they require supplementary costly infrastructure. User-relay assisted OFDMA-based networks are promising candidates to fulfill the demanding coverage and capacity requirements of future wireless networks in a cost efficient way. Thus, they have become popular as a complementary solution to fixed relay networks. Generic frame structure that divides the resource allocation frame into two subframes is mostly used in the literature for fixed and user-relay assisted networks in which it is assumed that a user can act as a destination and a relay simultaneously. However, it may be difficult to apply this assumption to practical systems because of the limitations of the current transceiver design. Thus, we propose a novel frame structure for user-relay assisted OFDMA-based wireless networks in order to cope with these drawbacks. The efficient radio resource management algorithms including relay selection and resource allocation are developed in order to exploit the opportunities of the proposed frame structure.

Development of Signal Recovery Algorithm for Overcoming PAPR in OFDMA Communication System

“…However, the cutting processes cause the OFDMA signal to distort. BER is also improved [4,8,43,[55][56][57].BER is the ratio of the error number to the number of bits indicated. By counting the numbers of errors at the receiver with enough symbols registered, BER can be calculated directly.…”

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.…”

Resource allocation and relay selection in full-duplex cooperative orthogonal frequency division multiple access networks

“…On the other hand, all of these papers only consider the downlink transmission. [11], [12] and [15] are based on orthogonal frequency division multiple access (OFDMA) that using subcarrier pairing in the relay network can result in the frequency diversity, and hence, improves system performance [16]. Some papers propose a scenario that there are one source and destination and some relays between them [13].…”