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M2M/online gaming are considered as key applications in LTE and LTE-advanced networks. However, for most of these applications whose traffic is sporadic and some of them require very low latency, they are not well supported by the current LTE and LTE-advanced systems due to the large signaling overhead. This paper proposes two methods to address this problem. The first method provides a co-optimization...
Asymptotically optimal schemes for both single and dual-source cases with low-latency are addressed in this research. Single-source two-way protocol with non-coherent reception is introduced and its asymptotic behaviour is studied. The protocol consists of a data phase and a control phase which can go on up to N rounds. An upper bound on the distortion is derived for a two-round protocol. It is also...
Femtocells are small cellular base stations targeting in-home usage and deployed by end-users. Because of the unplanned nature of their deployment, they can suffer from severe inter-cell interference with neighboring femtocells in dense deployments. In addition, coordination is hardly feasible due to delays induced by the backhaul infrastructure of these home femtocell networks. We propose a novel...
Accurate information regarding a cognitive radio user's location and environment can enhance the adaptive and spectral awareness capabilities of cognitive radio systems. In this paper, a single-path multiband Time-of-Arrival (TOA) positioning technique for cognitive radio is proposed and the performance evaluated using maximum-likelihood (ML) location estimation for a typical rural scenario where...
In the context of multiuser relay-aided multi-way communications, we identify and meet the optimal degrees of freedom (DOF) for different multiuser uplink-downlink settings of practical importance. Under the imposed constraint of using simple linear techniques, the proposed solutions draw from interference-neutralization (IN) methods which linearly manipulate signals in time and space, and manage...
This paper considers a communication network comprised of two nodes, which have no mutual direct communication links, communicating two-way with the aid of a common relay node (RN), also known as separated two-way relay (TWR) channel. We first recall a cut-set outer bound for the set of rates in the context of this network topology assuming full-duplex transmission capabilities. Then, we derive a...
A recent idea of exploiting the promised gains of multi-user MIMO for future cellular standards as LTE by intelligent interference aware receivers instead of suboptimal singleuser receivers is quite promising. However this detection strategy is based on the exploitation of the structure of interference which necessitates the knowledge of the constellation and precoder of the co-scheduled user equipment...
The work described in this paper proposes two Smart Hybrid-Automatic Repeat Request (SHARQ) schemes with incremental redundancy, that are developed for a dual-hop network of two relays implementing cooperative communication. In a dual-hop network consisting of multiple relays, one of the most challenging tasks is to determine an appropriate trade-off point between the end-to-end block-error rate (BLER)...
In this paper, we assess the random coding error exponents (EEs) corresponding to decode-and-forward (DF), compress-and-forward (CF) and quantize-and-forward (QF) relaying strategies for a parallel relay network (PRN), consisting of two sources, two relay stations (RSs) and single destination where the RSs access to the destination via orthogonal, error-free, limited-capacity backhaul links. Among...
We consider the role of independent single antenna relays in allowing for interference cancellation and for multiplexing of uplink and downlink communications, in the presence of multiple interfering users. For a specific practical scenario of interest, we construct interference neutralization schemes that are simple, distributed and which encode over both space and time, to achieve performance improvements...
In this paper, we propose a novel low-complexity interference-aware receiver structure for multi-user MIMO that is based on the exploitation of the structure of residual interference. We show that multi-user MIMO can deliver its promised gains in modern wireless systems in spite of the limited channel state information at the transmitter (CSIT) only if users resort to intelligent interference-aware...
A relatively recent idea of extending the benefits of MIMO systems to multiuser scenarios seems promising in the context of achieving high data rates envisioned for future cellular standards after 3G (3rd Generation). Although substantial research has been done on the theoretical front, recent focus is on making Multiuser Multiple-Input Multiple-Output (MUMIMO) practically realizable. This paper presents...
We consider in this paper high spectral efficiency bit interleaved coded modulation (BICM) MIMO system where, after serial to parallel conversion and per antenna coding, spatial data streams are simultaneously transmitted by using an antenna array. We carry out the performance analysis of an earlier proposed detection algorithm for such system which is based on the combination of linear and non linear...
Stopping criteria for the iterative decoding of low-density parity-check codes are considered. For a successful decoding task an inherent stopping criterion is used: the fulfillment of all parity-check constraints. For an unsuccessful task the decoder usually completes a preset maximum number of iterations. Proper iteration control is required to save energy and time on unnecessary decoder operation...
This paper presents a dynamic power management strategy for the iterative decoding of low-density parity-check (LDPC) codes. We propose an online algorithm for adjusting the operation of a power manageable decoder. Decision making is based upon the monitoring of a convergence metric independent from the message computation kernel. Furthermore we analyze the feasibility of a VLSI implementation for...
In this paper, we look at the combined effect of spatial and temporal correlation on low complexity max log MAP detector in the scenario of interference suppression. We consider narrowband MIMO channel which experiences spatially and temporally correlated wide sense stationary Rayleigh fading. Employing moment generating function (MGF)-based approach, we derive upper bounds of coded pairwise error...
We consider a multi-pair two-way relay channel (TWRC) where the single-antenna mobile terminals (MT) on each pair seek to communicate, and can do so, via a common multiple antenna relay station (RS). In the multi-pair TWRC, the main bottleneck on system performance is the interference seen by each MT due to the other communicating MT pairs. In this paper, we try to tackle this problem in the spatial...
Bit interleaved coded modulation (BICM) because of its improved diversity over fast fading channels is an attractive transmission scheme for future wireless systems. For coded BICM systems, receivers need to employ max log MAP demodulators (demappers) that calculate soft-decision metrics i.e. log-likelihood ratios (LLRs) for the decoder. The complexity of the calculation of these LLRs is exponential...
In this paper, we carry out the performance analysis of recently proposed low complexity max log MAP detector for interference suppression under the realistic imperfections of correlation and non Gaussian alphabets. We also incorporate MMSE detector in our analysis taking into account non Gaussian alphabets however intricacy in the analysis of correlated case restricts our analysis to the case of...
The downlink performance of cellular networks is known to be strongly limited by inter-cell interference. In order to mitigate this interference, a number of frequency reuse schemes have recently been proposed. This paper discusses a novel fractional frequency reuse (FFR) scheme combined with interference suppression for orthogonal frequency division multiple access (OFDMA) networks, which are currently...
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