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To date there is no practical means to evaluate the true word error probability (WEP) of a given turbo or LDPC code because typical decoders cannot achieve the performance of ML decoding. In this paper, we propose a viable methodology to establish tight bounds on the ML-decoding WEP for these codes through empirical simulation. Our framework centers on the efficient use of multiple-output decoding...
Applying interblock memory to binary linear block codes is a method to increase the transmission reliability by increasing the correlation among codewords. In this paper, we consider short block coding with interblock memory. Since short block codes can be efficiently decoded by employing the A∗ Algorithm, we investigate the performance of short block coding with interblock memory using the A∗ decoding...
Until recently, link adaptation and resource allocation for communication system relied extensively on the spectral efficiency as an optimization criterion. With the emergence of the energy efficiency (EE) as a key system design criterion, resource allocation based on EE is becoming of great interest. In this paper, we propose an optimal EE-based resource allocation method for the scalar broadcast...
This paper investigates a new constrained relay selection scheme for two-way relaying systems where two end terminals communicate simultaneously via a relay. The introduced technique is based on the maximization of the weighted sum rate of both users. To evaluate the performance of the proposed system, the outage probability is derived in a general case (where an arbitrary channel is considered),...
The fixed-complexity sphere decoder (FSD) has been proposed to attain the near-optimal performance achieving the same diversity order as the maximum-likelihood decoder (MLD) recently. However, it suffers great redundant computations resulting in high power consumption. In this paper, we conduct an improved algorithm for the original FSD by using early termination (ET). This algorithm (abbreviated...
We consider the application of interference alignment (IA) to the cellular case with constant MIMO channel coefficients. Neglecting the weakest interferers in the network, we introduce an algorithm to obtain a partially connected (in particular, L-interfering) network, over which the feasibility of IA can be analyzed simply. We consider the application of IA over the obtained L-interfering network,...
We consider a random access primary network. At the beginning of each time slot, a number of secondary users sense the channel and make an access decision based on the spectrum sensing outcome and the channel state information (CSI). Specifically, the channel is accessed by a secondary transmitter with a probability that depends on both the sensing metric and the gain or signal-to-noise-ratio (SNR)...
In this work, we revisit the issue of fair resource allocation in relay-enhanced wireless networks. Our focus this time is on Type-1a relays as proposed for LTE-Advanced. The latter operate as out-band relays, i.e., the backhaul and relay access link use separate carrier frequencies. If carrier aggregation is applied at the macro base station, the backhaul carrier may also contain part of the macro...
LTE-Advanced is the evolutionary path from LTE Release 8. It is designed to significantly enhance the performance of LTE Release 8 in terms of higher peak data rates, improved system capacity and coverage, and lower latency. These enhancements allow LTE-Advanced to meet or exceed the IMT-Advanced requirements and are being considered as part of LTE Release 10. In this paper, some of the physical layer...
The back-pressure based scheduling policy originally proposed by Tassiulas et al. in [1] has shown the potential of solving many fairness and network utilization related problems of wireless multi-hop networks. Recently, the scheduling policy has been adapted in random medium access protocols such as CSMA/CA using prioritization of MAC layer transmissions. Here, MAC priorities are used to provide...
In this paper, the queue dynamics of secondary users (SUs) in a multi-SU and multi-channel cognitive radio network is analyzed to obtain the expressions of quality of service (QoS) metrics. Specially, in the analysis, we take several lower-layer mechanisms and settings into account, including automatic repeat request (ARQ), finite-size buffer, adaptive modulation and coding (AMC) and non-ignorable...
Orthogonal Frequency Division Multiple Access (OFDMA), Multiple Input Multiple Output (MIMO), and Adaptive Modulation and Coding (AMC) are advanced signal processing techniques introduced in the wireless 3GPP LTE standard. In MIMO-OFDMA system, by taking advantage of the spatial dimension and depending on the time-varying wireless channel condition, the most efficient modulation and coding with spatial...
In this paper, we present two novel Resource Allocation (RA) strategies based on the Signal-to-Leakage-plus-Noise-Ratio (SLNR) for the downlink (DL) of Coordinated Multi Point (CoMP) transmission in LTE-Advanced (LTE-A) system. The proposed RA strategies select the UEs that can efficiently share the same Resource Block (RB) without degrading the overall throughput by using the SLNR metric. In addition,...
Heterogeneous networks (HetNets) are expected to be one of the major performance enhancement enablers of LTE-Advanced. Due to significantly challenging interference scenarios, enhanced inter-cell interference coordination (eICIC) based on almost blank subframes (ABS) is the key technology enabler that makes HetNets a reality. The key factor determining the gain of ABS-based eICIC is the configured...
This paper quantifies the impact of topological characteristics on the performance of single radio multichannel IEEE 802.11 mesh networks. Topological characteristics are the number of nodes per subnetwork, the hop count, the neighbor node density, the hidden nodes, the number of nodes in the neighborhood of the gateway, and the hidden nodes in the neighborhood of the gateway. Network performance...
Ad-hoc networks are independent of any infrastructure. The nodes are autonomous and make their own decisions. They also have limited energy resources. Thus, a node tends to behave selfishly when it is asked to forward the packets of other nodes. Indeed, it would rather choose to reject a forwarding request in order to save its energy. To overcome this problem, the nodes need to be motivated to cooperate...
In this paper we propose an energy efficient image transmission strategy for wireless sensor networks, which combines wavelet-based image decomposition and cooperative communication. In the proposed scheme we use selective decode-and-forward (SDF) cooperation, so that a relay node collaborates with the source by forwarding only a lower-resolution version of the original image, obtained via discrete...
We present a new distributed protocol for setting up and maintaining a backbone for multi-hop mobile networks with multiple radio interfaces. Our solution, termed MM-Backs, is effective in producing backbones with limited size, while being robust and reliable in the face of node mobility. We also describe how MM-Backs can be used to transparently support ad hoc routing, without the need to modify...
Sensor selection is to pick out an appropriate subset of active sensors for reliable collaborative sensing. Naturally, the selected sensors should be as uncorrelated as possible to have more independent sensing outputs for information fusion. In this paper, various uncorrelation metrics are unified by the concept of Bregman divergence. The sensor selections are then systematically formulated as NP-hard...
Without the assumption of contemporaneous end to end connectivity in challenged wireless networks, Delay Tolerant Networking (DTN) routing is an important research area. The contribution in this paper is to take advantage of the proposed DTN geographic replication to overcome the limitation of topology based utility replication, since message replication is prevented due to the local maximum problem...
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