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In 3GPP LTE-Advanced networks deployed with type I relay nodes (RNs), resource partition is required to support in-band relaying. This paper focuses on how to partition system resources in order to attain improved fairness and efficiency. We first formulate the generalized proportional fair (GPF) resource allocation problem to provide fairness for all users served by the evolved node B (eNB) and its...
The interference management problem in cognitive radio networks is in this paper, tackled from the transmitter power control perspective so that transmissions by cognitive radios does not violate the interference level thresholds at incumbent users. We modify cellular distributed power control algorithms to suit the cognitive radio framework by exploiting spectrum use and radio environment knowledge...
In this contribution, we consider the performance of the CSMA MAC protocol in multi-hop ad hoc networks in terms of "aggregate multi-hop information efficiency". Our model consists of a wireless network where transmitter nodes are distributed according to a homogeneous 2-D Poisson point process, and packets are generated following a Poisson distribution. Each packet is forwarded to its destination...
We propose algorithms to address the spectrum efficiency and fairness issues of multi band multiuser Multiple-Input and Multiple-Output (MIMO) cognitive ad-hoc networks. To improve the transmission efficiency of the MIMO system, a cross layer antenna selection algorithm is proposed. Using the transmission efficiency results, user data rate of the cognitive ad-hoc network is determined. Objective function...
We consider a general wireless channel model for different types of code-division multiple access (CDMA) and space-division multiple-access (SDMA) systems with isometric random signature/precoding matrices over frequency-selective and flat fading channels. We derive deterministic approximations of the Stieltjes transform, the mutual information and the signal-to-interference-plus-noise ratio (SINR)...
It is known that distributed power control in wireless ad-hoc networks is challenging, due to the inherent global coupling between concurrent transmissions interfering with each other. Observing that the globally optimal point lies on the boundary of the feasible region, we transform the utility maximization problem into a more structured problem in the form of maximizing the minimum weighted utility...
In this paper, we investigate joint relay and jammer selection in two-way cooperative networks, consisting of two sources, a number of intermediate nodes, and one eavesdropper, with secrecy constraints. Specifically, the proposed algorithms select two or three intermediate nodes to enhance security against the malicious eavesdropper. The first selected node operates in the conventional relay mode...
Recently, in multi-antenna wireless systems, the use of artificial noise (AN) in training and data transmission phases has been respectively proposed to achieve performance discrimination between a legitimate receiver (LR) and an unauthorized receiver (UR). For data transmission, an AN-aided beamforming (ANBF) scheme has been proposed where the message is sent towards LR using beamforming while AN...
The ideas of wireless network coding at the physical layer promise high throughput gains in wireless systems with relays and multi--way traffic flows. This gain can be ascribed to two principles: (1) joint transmission of multiple communication flows and (2) usage of a priori information to cancel the interference. In this paper we use these principles to devise new transmission schemes in wireless...
Interference in wireless networks is one of the key capacity-limiting factors. Recently developed interference-embracing techniques show promising performance on turning collisions into useful transmissions. However, the interference-embracing techniques are hard to apply in practical applications due to their strict requirements. In this paper, we consider utilizing the interference-embracing techniques...
Relay is used in LTE-Advanced cellular networks to assist eNB(evolved Node Base-station) for coverage extension and throughput enhancement. Compared to eNB, relay is advantageous on both equipment cost and site cost. How to deploy relays to maximize the performance gain with a reasonable cost subject to a number of system constraints such as interference caused and backhaul subframe allocation is...
It is common practice to model the base station (BS) locations in a cellular system by a grid, such as a hexagonal or square lattice. This model is usually analytically intractable as well as quite idealized. Therefore, system designers resort to complex simulations to evaluate network performance. In this paper, we introduce a new model for the base station locations based on a homogeneous Poisson...
We consider an underlay cognitive radio network, in which the cognitive users (also referred to as secondary users (SUs)) are allowed to access the licensed spectrum simultaneously with the primary users (PUs). Specifically we solve a beamforming and power allocation problem in the downlink with mixed quality-of-service (QoS) requirements where a set of SUs are required to achieve a specific signal-to-interference...
We consider the greedy scheduling based on the physical model in wireless networks with successive interference cancellation (SIC). There are two major stages in a scheduling scheme, link selection (to decide which link is scheduled next) and time slot selection (to deciding which slot is allocated to a given link). Most available schemes take a first-fit policy in the latter and strive to achieve...
We investigate multiple-input multiple-output broadcast channel with channel distribution information at the transmitter. We consider the fading-paper model with Nt transmit and Nr receive antennas. Near-optimal methods for designing the inflation factor matrix (choice of auxiliary random variable) to maximize the linear assignment capacity in a general fading channel model are proposed. Further,...
This paper studies a spectrum sharing scenario between an uplink cognitive relay network (CRN) and some nearby low power ad-hoc networks. In particular, the dynamic resource allocation of the CRN is analyzed, which aims to minimize the average interfering time with the ad-hoc networks subject to a minimal average uplink throughput constraint. A long term average rate formula is considered, which is...
Underwater Wireless Sensor Networks(UWSNs) could enable a broad range of applications. Data aggregation is a fundamental task in multi-hop wireless sensor networks; to the best of our knowledge, none of existing research works have addressed the interference-free data aggregation scheduling problem in UWSNs. In this paper, we formally define the data aggregation models in UWSNs, together with the...
In this paper, we deal with the scenario that a single secondary user attempts to opportunistically access the 3G Wireless CDMA Networks licensed to primary users. Different from the former works merely consider the channel as two state Markov process,, we expand the channel's availability into a multiple-state Markov process according to the transmission power of SU. We propose a cyclical, but not...
In this paper, we propose a distributed interference alignment which employs physical-layer network coding and superposition coding for successive-cancelling multiuser detection (MUD) receivers in K-pair bidirectional relaying networks. The proposed scheme enables the transmitter to align only partial interference while strong interference is cancelled by MUD, and the transmitter can have more degrees...
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