Vigneswara Rao Gannapathy

A smooth forwarding operation in wireless mesh network

The IEEE 802.11 Distributed Coordination Function (DCF) Medium Access Control (MAC) protocol is designed to efficiently facilitate the limited communication bandwidth of wireless channel. This protocol uses Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) mechanism. This mechanism continues suffer from throughput degradation when directly applied in multihop Wireless Mesh Network (WMN). The major reason for this poor performance is due to larger signaling overheads (RTS and CTS signaling packet) introduced in order to forward a single data packet in multihop WMN. This inefficient forwarding operation caused the throughput degradation signifficantly. Therefore, an efficient forwarding operation is proposed in this paper to reduce the amount of signaling overheads which are needed to forward a single packet in multihop WMN. The proposed protocol uses the capability of overhearing in order to forward the data packet from one hop to another hop. This process will continue until the data packet reaches the respective destination. As a result, the enhanced protocol reduces the latency caused by signaling thus improve its throughput in multihop WMN. The multihop network performances are evaluated analytically in terms of throughput and delay. Through the simulation, it is proven that the proposed protocol provides significant improvement in throughput and delay. The results show that the proposed protocol outperforms the existing IEEE DCF MAC protocol when it is evaluated in multihop WMN.

Concurrent MAC with Short Signaling for multi-hop Wireless Mesh Networks

The IEEE 802.11 Distributed Coordination Function (DCF) Medium Access Control (MAC) protocol continues to suffer from throughput degradation when directly applied in multi-hop Wireless Mesh Network (WMN). The Request-to-Send/Clear-to-Send (RTS/CTS) signaling partially solved hidden node problems however the exposed node problems remain unaddressed. The IEEE 802.11 MAC does not allow the exposed nodes to initiates its transmission for the entire duration of ongoing transmission over multi-hop network leads to throughput degradation. Moreover, the amount of needed signaling packets takes place at every hop reduces the overall multi-hop throughput significantly. This project proposes a set of enhancement to the existing IEEE 802.11 DCF MAC by enabling concurrent transmission by the exposed nodes and reduces the amount of signaling packets (CMAC-SS) required at every hop until the data packet reaches its destination. Analytical models are developed and simulated over quasi-static Rayleigh fading channel. The multi-hop network performances are evaluated in terms of throughput and delay. The CMAC-SS protocol outperforms the existing IEEE DCF MAC with more than 14% increase in overall throughput of multi-hop WMN.

Physical and MAC Cross Layer Design for Wireless Mesh Networks

Wireless mesh networks (WMNs) are an alternative technology for last-mile broadband Internet access that can support broadband services. However, for a WMN to be all it can be, considerable research efforts are still needed. For example, the available MAC and routing protocols are not scalable; throughput drops significantly as the number of nodes or hops in WMNs increases. Thus, existing protocols need to be enhanced or re-invented for WMNs. When advanced physical layer techniques, used, novel MAC protocols, especially multi-channel MAC, need to be proposed to utilize the agility provided by the physical layer. This paper presents an introduction to wireless mesh networks, IEEE 802.11, physical layer and Medium Access Control (MAC) cross layer design.

Analysis of Electromyography (EMG) Signal for Human Arm Muscle: A Review

Muscles provide motion in response to nerve impulses. There are two main categories of muscle can be distinguished based on their anatomy and the particular functions they perform. Skeletal muscles are the largest group of muscles control posture, generate heat, and provide motion control and are mostly influenced by the brain in conscious acts. Smooth muscles provide rhythmic motion outside the control of the brain. A nerve cell provides a train of impulses delivered to a group of muscles in which the impulses depolarize muscle cells and cause muscles to contract. Electromyography (EMG) is a technique for evaluating and recording electrical activity produced by skeletal muscles when the muscles are stimulated. Surface electromyography and needle electromyography are two general methods of recording the electrical activities of muscle tissue. In this project, surface electromyography will be used to test the analysis for human arm muscle. Electrodes placed on the skin surface can be used to monitor the coordination of entire muscle groups but will not reveal much about the individual muscle cells. Thorough testing will be done as the future work once the fabrication has been completed.

Wireless mesh networks: Cross layer design challenge!!

Recently, wireless mesh networks as a promising newcomer in wireless access technology, has caught the attention of networking industries. These networks are envisioned to support the wired backbone with a wireless backbone for providing internet connectivity to residential areas and office. WMNs have the potential to eliminate many of disadvantages by offering low-cost, wireless broadband Internet access both for fixed and mobile users. Cross-layer design have risks due to loss of protocol layer abstraction, incompatibility with existing protocols, unforeseen impact on the future design of the network, and difficult in maintenance and management. In order to improve protocol efficiency, cross layer design becomes indispensable. This article highlights some of the past achievement and promising research avenues for an important topic in the creation of future wireless mesh networks. This article also address the issue of cross layer networking in the physical layer, network layer and transport layer.

Network and medium access control (NET - MAC) layers for Wireless Mesh Network (WMN)

Wireless Mesh Networks provide a cost-efficient avenue to extend the coverage of WiFi networks by using multi-hop communication. The capability of enhancing coverage and capacity with low transmission power, wireless mesh networks (WMNs) play a significant role for broadband access with ubiquitous coverage. WMNs have emerged as a key technology for next-generation wireless networking. Because of their advantages over other wireless networks, WMNs are undergoing rapid progress and inspiring numerous applications. However, many technical issues still exist in this field. In order to provide a better understanding of the research challenges of WMNs, this paper presents a detailed review on MAC and Network layer for Wireless mesh network and also proposing innovative protocol that may improve throughput for multi-hop mesh communication. This paper also discussed the criteria that must be considered in order to design a scalable MAC for WMNs.

Ray-tracing propagation prediction for wireless mesh networks (WMNs)

Nowadays, a lot of research efforts and technical papers are done on ad-hoc networks and wireless local area networks (WLAN). Recently, however wireless mesh networking is attracting significant interest from academia, industry, and standard organizations because it is offer several favorable characteristics such as dynamic self-organization, easy maintenance and reliable services. A network with several transmitters and receivers that communicate to each other will form a mesh network topology. Once the transmitter launches a ray, it will be reflected, refracted or diffracted to any kind of surfaces such as the concrete wall. That process will decrease the received signal strength at the receiver. So, ray-tracing technique can be used to analyze the network performance. It is a method that used to determine the ray paths that emanate from the transmitter (Tx) and arrive at the receiver (Rx), and also an efficient approach in determining the propagation issues in wireless environment. So, this paper will be focused on Ray-Tracing techniques and WMNs theories.