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Recently, a novel single user weighted-transmitted reference (WTR) system has been proposed for high data rate ultra-wideband (UWB) communications. The WTR system not only achieves a superior performance but also supports high data rates and is robust to variations of both weighting coefficient and integration interval. Furthermore, it extremely reduces the sampling rate in comparison to the existing...
The use of multiple antennas at both the transmitter and receiver is well motivated by the substantial performance gains that can be realized, both in terms of an increase in achievable data rate and a decrease in error rate. The achievable data rate is characterized by the mutual information of the channel. In case of frequency selective multiple input multiple output (MIMO) channels, expressions...
MIMO (Mulitple Input Multiple Output) localization has attracted much attention recently. In such schemes, using multiple antennas at transmitter and receiver sides provides spatial diversity. On the other hand, Passive Coherent Location (PCL) by using the illuminators of opportunity (such as FM, GSM, DVB transmitters) has shown a number of advantages. In this paper, we explore the possibility of...
In this paper, we compare the two most common types of statistical models for V2V channels: the tapped-delay line, and the geometry-based stochastic model. We first provide a description of each model type. Model adaptations and options are described, as is model flexibility, and ability to replicate statistics that agree with measurements. We quantify each model's complexity, and show that the modified...
The MR-FDPF (Multi-Resolution Frequency-Domain Partial Flow) method has proved to be an efficient tool for the indoor radio coverage prediction. In this paper, a new approach is proposed allowing extracting the fading statistics for indoor radio channels based on the electric field strength predicted with the MR-FDPF method. The performance of the proposed approach is verified both by simulations...
In this paper, we investigate the maximum inter-site distance (ISD) for performing joint signal processing between cooperative base stations. As a metric, we use the maximum excess delay measured at 95% point of the cumative power delay profile from all base stations. For the distance-dependent channel parameters, we consider Greenstein's statistical propagation model, which we extended for broadband...
Traditional handoff algorithms generally cannot keep both the average number of unnecessary handoffs and handoff decision delays low. In order to achieve this goal, this paper presents a novel pattern recognition based handoff algorithm which uses a neural network as a classifier. It is based on the fact that in micro-cellular environments in cities, users often move on predetermined paths and as...
In this paper, we present novel results on polarization study for Ultra-WideBand (UWB) wireless channel in indoor environments. The measurements were conducted for Line of Sight (LOS) and Non-Line of Sight (NLOS) scenarios in indoor office environments covering a large frequency band from 2–6 GHz. Given the large band and the importance of UWB propagation parameters including polarization, the results...
In a cooperative multi-cell network we propose to simultaneously demodulate the uplink signal coming from mobile terminals (MTs) with multiple base stations (BSs) for a joint decoding of the data packets. However, limited backhaul capacity and BS demodulation capabilities limits the number of cooperating BSs. In this paper we consider MTs using a hybrid automatic repeat request (HARQ) protocol for...
Cognitive radio (CR) emerges as a key technology to enhance spectrum efficiency and thus creates opportunistic transmissions over links. Supporting the routing function on top of numerous opportunistic links is a must to route packets in a general cognitive radio network (CRN) consisting of multi-radio systems. However, there lacks complete understanding of these highly dynamic available links and...
We propose the dynamic BS-selection schemes for distributed wireless MIMO links, which aim at minimizing the average base-station (BS) usage while satisfying the specified statistical delay quality-of-service (QoS) constraint characterized by the delay-bound violation probability. In particular, the distributed transmission system consists of a number of location-independent BS's, a central server,...
This paper is aimed to evaluate the effect of feedback delay on the performance of closed loop power control in CDMA System. Even though power control can mitigate the problem fluctuation due to fading, however due to the feedback delay, that advantage is invisible if this parameter is not decreased. Feedback delay is the total time that is taken by the power control from the mobile transmit signal...
The features that DTN protocol architecture offers are particularly appealing to handle intermittent links and disruption events, by means of the Custody Transfer option. On the other hand, the implementation of long erasure codes proved to be promising to contrast short fading events in long delay networks, where the high latency makes the use of ARQ schemes less profitable. This paper proposes a...
In this paper, a novel adaptive maximum ratio combining (MRC) rake receiver using genetic algorithm (GA) is proposed. The proposed adaptive GA Rake receiver uses GA to adaptively select the delays of Rake receiver fingers depending on the channel impulse response. It adaptively selects the delays that will allow the Rake receiver to capture most of the energy of the multipath components with less...
In coding theory, concatenated codes form a class of error-correcting codes that are derived by combining an inner code with an outer code. This is a solution to the problem of finding a code that has both exponentially decreasing error probability with increasing block length and polynomial-time decoding complexity. The work presented in this paper, provides link level performance analysis of non-line...
In this paper, a novel OFDM symbol timing recovery method, which is robust to doubly selective fading channels and carrier frequency offset, is proposed for the mobile terminals of CMMB system. The time slot timing synchronization is accomplished by using the inverse sliding correlation between the segmenting Sync sequences, which possess the inverse conjugate symmetry (ICS) characteristic. Furthermore,...
The cooperative relay protocol is investigated in heterogeneous wireless networks. To analyze the handover impact of a cooperative relay node on a heterogeneous environment, we propose two typical mobility scenarios to evaluate the performance metrics, such as the capacity, outage probability, and service delay. The difference from a three-node link performance evaluation is that the node speed is...
This paper proposes a novel admission control (AC) algorithm for guaranteed quality of service (QoS) to all users. The proposed solution provides better utilization of system capacity using adaptive modulation (AM). A scheduler based on a per user priority function is also given in this paper. The AC is given by allocating the exact number of slots for each user that will meet its QoS. For every new...
Cross-layer algorithms that jointly allocate resources at different layers are known to foster the communication performance in wireless networks. Recent works have shown that fading and queue information are among the most critical parameters to consider in cross-layer designs. Motivated by those findings, this work develops optimal algorithms that use instantaneous fading and queue length information...
Linear precoding plays an important role in the spatial multiplexing multiple-input multiple-output (MIMO)-orthogonal frequency-division multiplexing (OFDM) systems which are considered one of the primary candidates for the physical-layer techniques in the next-generation wireless communication systems. It requires the channel state information (CSI) at the transmitter to adapt the transmitted signal...
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