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A signal forwarding strategy with constraints on interference and noise leakage to multiple neighboring nodes and quality of services (QoS) to multiple destination nodes is proposed. The objective is to relay signals from multiple sources to multiple destinations using a set of relay nodes with minimum possible transmission power while achieving desired QoS for destination nodes and minimum possible...
The outage analysis of networks with randomly distributed nodes has been mostly restricted to the case of Poisson networks, where the node locations form a homogeneous Poisson point process. In this paper, we show that in great generality, the outage probability, as a function of the density of interfering nodes ??, approaches ?????? as ?? goes to zero, where ?? and ?? are the spatial contention and...
We propose an adaptive radio resource allocation algorithm for a multiple-input multiple-output (MIMO) orthogonal frequency division multiple access (OFDMA) based uplink cognitive radio network (CRN). The CRN has multiple secondary users (SUs) coexisting with multiple primary users (PUs). The aim is to admit as many SUs as possible in various subcarriers while ensuring no interference is leaked to...
A cooperative relaying scheme is proposed for an underlay cognitive radio network where relays use their beam steering capability to impose target SINRs at the secondary user terminals whilst keeping the interference and noise leakage to the primary users below a threshold. The scheme is developed to incorporate per relay antenna power constraint that limits the power emitted by the relays. The scheme...
We propose a cooperative relaying strategy for wireless mesh networks where a set of relay nodes assists forwarding signals from multiple sources to multiple destinations. A semi- definite programming framework is used to ensure target SINRs at the destination are achieved with minimum possible transmit power at the relay layers. The proposed algorithm also considers various level of quantization...
Cognitive radio networks opportunistically operate in frequency bands that have been licensed to other networks. Therefore, communication between unlicensed users should ensure the interference leaked to the licensed users is kept below an acceptable level while achieving the required quality of services. In this paper, we extend SINR balancing technique to serve multiple cognitive users in the downlink...
In order to obtain a good balance of bit error rate (BER) across channels, the geometric mean decomposition (GMD) is introduced to replace the singular value decomposition (SVD) for precoding in the downlink of a multiuser multistream multiple-input multiple-output (MIMO) system. By combining GMD with a block diagonalization method, we obtain two kinds of precoding schemes: iterative nullspace-directed...
Cognitive radio networks have the ability to efficiently utilize the scarce radio spectrum by allowing unlicensed users to access the licensed frequency bands in the absence of licensed users. Transmit beamformers can be designed by setting constraints on the interference temperature of the licensed users and signal to interference and noise ratios (SINRs) of the cognitive users. This design is however...
Cognitive radios have the ability to efficiently utilize the spectrum, by intelligently sensing absence of licensed users and transmitting signal through the frequency bands that are not occupied. Spatial diversity techniques at the cognitive base station could further help in controlling the interference temperature levels of the licensed users when signals are transmitted to unlicensed users. This...
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