Throughput Of Wireless Channel Research Articles

Radio Communication in Curved Tunnels: MIMO Channel Capacity for Rail Transit Applications

The rail transportation industry has seen a growing interest in the use of radio-access technology (RAT) for critical and noncritical services to improve safety/reliability, performance, and passenger experience. There is a practical incentive to investigate how to improve wayside-onboard wireless channel throughput and transmission reliability to address the different requirements of data transmission. To this end, during the past two decades, the theory and practice of multiple-input/multiple-output (MIMO) communications has solidified to the point where MIMO is now the main infrastructure for several legacy and emerging radioaccess standards.

RESULTS AND TOOLS FOR EVALUATING THE EFFECTIVENESS OF FOCUSING SYSTEMS TO IMPROVE ACCESSIBILITY IN WIRELESS NETWORKS

The widespread use of wireless technologies leads to an ever-increasing number of users and permanently functioning devices. However, the growth of the number of wireless users in a limited space and a limited frequency range leads to an increase in their mutual influence, which ultimately affects the throughput of wireless channels and even the performance of the system as a whole. The article presents the statistics and tendencies of the distribution of wireless networks of the IEEE 802.11 standard systems, as well as analyzes the main problems that arise during the expansion of their use. Substantiation and choice of ways to overcome these difficulties largely depends on the objective control of radiation parameters of access points and subscriber funds in a particular environment. The review of the state control facilities provided by the developers of the equipment is presented, and author's variants of experimental measuring complexes are offered, allowing to control signal and information parameters of Wi-Fi systems. The experimental results obtained with the use of the indicated means, obtained using the accelerating metal-plate lens as an additional autonomous element for focusing the field, including for MIMO systems, the effect of the accelerating metal-plate lens on the spatial distribution of the field, on the spectral structure of the signal are presented. In addition, polarization effects were investigated. Possible ways to further increase the availability, integrity of information and energy efficiency of wireless access systems are discussed. The authors propose simpler and less costly options for increasing the direction of radiation on the basis of an accelerating metal-plate lens, experimentally tested, as well as the use of zone zoning on the path of the computer.

Throughput analysis of wireless channel in boosting modes

In addition to the basic transmission mode, leading manufacturers of integrated circuits for wireless devices such as Atheros, Broadcom and TexasInstruments insert a number of additional modes into their products, aimed at increasing the throughput of wireless channel of the IEEE 802.11g standard, the so-called boosting modes. The analysis of the additional boosting modes for the wireless channel of the IEEE 802.11g standard was performed in the paper. It is shown that in contrast to the basic transmission mode for these modes, there are no mathematical models and throughput studies of wireless channels which operate in these modes. The mathematical models for calculating the maximum throughput of the wireless channel of the IEEE 802.11g standard for boosting modes: CompressionMode, BurstingMode, FastFrames and DynamicTurbo were obtained. Mathematical models analytically express the dependence of the maximum throughput of the wireless channel on the data frame size. Using the obtained models, a study of the maximum throughput of the wireless channel of the IEEE 802.11g standard for the given transmission modes was carried out. Studies have shown that these modes provide an increase in the maximum throughput of the wireless channel from 33% to 50% compared with the basic transmission cycle of the IEEE 802.11g standard. Based on the studies, a conclusion on the feasibility of using these modes for increasing the throughput of wireless networks was made. For each of the modes, upper limits of the throughput increase of the wireless channel of the IEEE 802.11g standard were defined.

The Details of Virtual Contention Window Concept for 802.11 IBSS Wireless Local Area Network Mathematic Modeling

The concept of a virtual contention window for assessment of temporal and probabilistic characteristics of the processes occurring in the wireless LAN 802.11 is considered. The relations for determining the transmission time delay of the data package, the uneven of transmission time, throughput of wireless channel, the probability of packet loss for networks with saturated load are proposed in this paper.

On Throughput Performance of Decode and Forward Cooperative Relaying With Packet Combining and ARQ

Cooperative Diversity can be used by wireless nodes to take the benefit of broadcast nature and inherent spatial diversity of wireless channel to relay messages for each others. This helps to propagate redundant signals over multiple paths, which can be used to combat the channel noise and fading effects. We investigate the use of packet combining in cooperative diversity scenario. In our approach we exploit this inherent spatial diversity alongwith the inherent time diversity in ARQ retransmissions. Further different channels have different fade levels or channel conditions. Maximal Ratio Combining of packets at the receiver improves the total Signal to Noise Ratio at the receiver, improving the throughput in wireless channel. Decode and Forward Relay can allow the opportunistic relay of the packets. In opportunistic relay of packets, the packet is relayed only when the direct transmission from source to destination fails. This saves the resources by avoiding the relay of packets, when not required. In this paper we propose the relaying scheme with packet combining at the destination. We investigate the BER and throughput performance of the scheme in AWGN and fading channel with and without MRC combining and compare them.

The concept of Virtual Contention Window for 802.11 IBSS wireless local area network mathematic modeling

The concept of a virtual contention window for assessment of temporal and probabilistic characteristics of the processes occurring in the wireless LAN 802.11 is considered. The relations for determining the transmission time delay of the data package, the uneven of transmission time, throughput of wireless channel, the probability of packet loss for networks with saturated load are proposed in this paper.