In this paper, we perform a comparative evaluation of characteristics multi-hop transmission of typical omni-directional MAC protocol IEEE 802.11 DCF and three directional MAC protocols. We consider the validity of the directional MAC protocols and problems. Additionally, we describe the suitable environment when a directional MAC protocol is used. Furthermore, we propose three schemes as deali...

Improvements in wireless sensor network (WSN) technology have resulted in a large number of applications. WSNs have been mainly used for monitoring applications, but they are also applicable to target tracking, health care, and monitoring with multimedia data. Nodes are generally deployed in environments where the exhausted batteries of sensor nodes are difficult to charge or replace. The prima...

Medium Access Control (MAC) Protocol are designed to improve energy efficiency inorder to prolong lifetime of node in Wireless Sensor Networks, where they exploit listen/sleep cycles to conserve energy. These cycles of nodes influence the network performances such as energy efficiency, packet latency and throughput in these networks. The issue of performance enhancement of wireless networks in ...

Medium access control (MAC) protocols in a cognitive radio network (CRN) are required to increase spectral efficiency and achieve high data rate for secondary users (SUs). Many MAC protocols use a single control channel with a bottleneck problem. In this paper, we propose a multichannel MAC protocol using dicontiguous orthogonal frequency division multiplexing (D-OFDM) in a CRN. Since D-OFDM te...

Medium access control (MAC) protocols coordinate channel access between wireless stations, and they significantly affect the network throughput of wireless ad-hoc networks. MAC protocols that are based on a multichannel model can increase the throughput by enabling more simultaneous transmission pairs in the network. In this paper, we comprehensively compare different design methods for multich...

Many Carrier Sense Multiple Access (CSMA) and Time Division Multiple Access (TDMA) based medium access control (MAC) protocols for vehicular ad hoc networks (VANETs) have been proposed recently. Contrary to the common perception that they are competitors, we argue that the underlying strategies used in these MAC protocols are complementary. Based on this insight, we design CTMAC, a MAC protocol...

In this paper, we have proposed some changes to MAC protocol for improving the performance of transport layer in cognitive radio ad-hoc networks. We have studied effects of different MAC and routing protocols on TCP in cognitive radio technology enabled environments. We have reviewed performance of TCP in two different situations. In first situation, all users are secondary users while in secon...

Due to the characteristics of underwater acoustic channel, media access control (MAC) protocols designed for underwater acoustic sensor networks (UWASNs) are quite different from those for terrestrial wireless sensor networks. Moreover, in a sink-oriented network with event information generation in a sensor field and message forwarding to the sink hop-by-hop, the sensors near the sink have to ...

A favorable technique is using directional antennas for high –speed wireless personal area networks and local.A new MAC protocol for wireless ad hoc networks which is referred to as New deafness-aware MAC(NDA-MAC) is proposed in this paper. There are many directional MAC protocols which have been proposed, but have not broadly solved the problem of deafness. We are proposing NDA-MAC protocol wh...

An area of growing interest has been to apply directional antennas to MANET protocols, which typically assumed a uniform equipment of omnidirectional antennas. In contrast to omnidirectional antennas, directional antennas have the benefits of reduced collision and extension of communication distance in a narrower range of directions. Existing work that applies directional antennas to MANET most...