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In the current inter-vehicle communication (IVC) systems such as IEEE802.11p, the CSMA/CA scheme for the MAC scheme and the OFDM for the modulation scheme are most commonly used for the media access scheme and the modulation scheme respectively. These systems are assumed to be used in the application such as safety driving assistance, reducing traffic congestions and so on. On the other hand, since...
We propose a novel method to maximise the aggregate throughput of an enhanced IEEE 802.15.4 gateway. By exploiting the gateway's beamforming antenna array and successive interference cancellation (SIC) we simultaneously increase range and maximise throughput. Our algorithm organises nodes into clusters, with each cluster assigned a unique spreading code and target gateway receive power. Within a cluster,...
This paper examines the efficiency of employing energy detectors in a multi-user network, whose nodes are spatially distributed in a geographic area and employ a CSMA MAC protocol to access the channel. It has been observed that explicit expressions for the analysis of imperfect physical carrier-sensing MAC protocols using energy detection are non-existent in the literature. We, therefore, present...
The IEEE 802.11 standardization group has recently ratified 802.11ac as the newest major amendment of the 802.11 family of Wi-Fi standards. While 802.11ac has specified a number of improvements over 802.11n such as: (i) 8 spatial streams (ii) mandatory bandwidth of 80 MHz and (iii) multi-user MIMO on the downlink, these improvements mostly target to improve the per-link throughput, and in case of...
Wireless communication systems based on multiple input-multiple output (MIMO) in combination with orthogonal frequency division multiple access (OFDMA) and space division multiple access (SDMA) are flexible, spectrally efficient and of high capacity. These systems can allocate frequency, time, and space resources adaptively among mobile stations (MSs). In order to perform an effective resource allocation...
In this paper, we address the multiuser detection problem in the presence of strong interference, mixture of Gaussian and α-stable noises. We initially obtain locally optimal (LO) detection rule for this problem which can almost completely suppress interference effect and combat α-stable noise to some extent using oversampling in the receiver or channel coding in the transmitter. Then, we derive a...
The operation of wireless cellular networks can be efficiently supported by secondary small cells that are deployed on-demand in traffic hotspots within the coverage area of primary network cells. In view of the growing traffic demand and the limited spectrum available, the objective of this study is to examine the conditions under which the secondary base stations can share the same communication...
Because of the high system capacity and excellent capability against narrowband interference (NBI), Direct Sequence-Code Division Multiple Access (DS-CDMA) is widely used in Geosynchronous Earth Orbit satellite systems. However, due to the existence of the uncertain non-cooperative external interference, traditional colored noise suppression methods cannot achieve high performance in DS-CDMA systems...
We investigate the amount of radio spectrum re- quired for reliable vehicle-to-vehicle (V2V) communication for traffic safety. The basic feature of the traffic safety application is that it uses periodical broadcasts of status messages containing the location and velocity of transmitting vehicles. In our study we consider two dominant technologies for V2V communication, namely IEEE 802.11p and self-organizing...
This paper investigates the problem of network selection in access control for heterogeneous networks of WCDMA/WLAN. To optimize the network selection decision policy, an optimization equation is defined with the objective of maximizing the total rewards, and then a new Q-learning Based Network Selection (QBNS) mechanism is proposed to solve the equation. In the QBNS Algorithm, Q-learning algorithm...
This study examines the trade-offs related to the problem of coverage auto-configuration of open access small cells (SC) that (i) are on-demand deployed in the macro-cells (MC) of a W-CDMA network, and (ii) operate in the same frequency channel as the hosting/neighboring MCs. The goal is to identify stable and practically detectable equilibrium states whose achievement can represent an optimality...
Coordinated Multi-Point transmission (CoMP) and Multiple-Input Multiple-Output (MIMO) antenna systems are two promising concepts to achieve high spectral efficiency and substantially mitigate the interference at the cell border inside one cluster. However, the gains promised by these techniques can severely be degraded in a multi-cluster environment. Therefore, power control plays a crucial role in...
In this paper, we investigate a super dense cellular deployment case in which the cells are continuously added in order to increase the total network capacity. The effect of the other cell interference in the HSPA network is analyzed, which provides an insight into the aggregated interference impact on the cell capacity. The network capacity performance with varying cell densities has been studied...
Recently, Multiflow transmission has been standardized as part of Multipoint High-Speed Downlink Packet Access (HSDPA). Multiflow schemes enable cell-edge HSDPA users to receive simultaneous data streams from multiple serving cells leading to improved user experience. The standard considers a single transmit antenna for each serving cell in a distributed Per Antenna Rate Control (PARC) manner. This...
The objective of a wireless multiaccess communication system is to distribute limited wireless channel resources efficiently and fairly among its users. Solutions for multiaccess communications have been approached with very different perspectives of the same problem, among them information-theoretic approaches at the physical layer, random access at the media access layer, and packet scheduling at...
Full-duplex has emerged as a new communication paradigm and is anticipated to double wireless capacity. Existing studies of full-duplex mainly focused on its PHY layer design, which enables bidirectional transmission between a single pair of nodes. In this paper, we establish an analytical framework to quantify the network-level capacity gain of full-duplex over half-duplex. Our analysis reveals that...
Game-theoretic modeling and equilibrium analysis have provided valuable insights into the design of robust local control rules for the individual agents in multi-agent systems, e.g., Internet congestion control, road transportation networks, etc. In this paper, we introduce a non-cooperative MAC (Medium Access Control) game for wireless networks and propose new fully-distributed CSMA (Carrier Sense...
In this paper an analytical approach is presented to determine the impact of frequency offset, timing jitter and additive white Gaussian noise (AWGN) on the bit error rate (BER) performance of a multi-carrier direct-sequence code division multiple access (MC-DS-CDMA) system over a Rayleigh Fading Channel. The analysis developed the pdf (probability density function) at the receiver considering combined...
In this paper, we propose transmission of video signal at one rate and data signal at another rate using fast frequency hopping code division multiple access (FH CDMA) over wireless fading conditions. In this method modulation codes of any desired length and weight can be used on top of FH CDMA and frequency hopping patterns can also have any desired length and weight, which makes the system to easily...
In this work, we propose a cross-layer design strategy based on a joint successive interference cancellation (SIC) detection technique and a multi-relay selection algorithm for the uplink of cooperative direct-sequence code-division multiple access (DS-CDMA) systems. We devise a low-cost greedy list-based SIC (GL-SIC) strategy with RAKE receivers as the front-end that can approach the maximum likelihood...
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