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Multi-user multi-input multi-output (MU-MIMO) system has attracted the 4 th generation wireless network as one of core technique for performance enrichment. In this system rate control is a challenging problem and another problem is optimization. Proper scheduling can resolve these problems by deciding which set of user and at which rate the users send their data. This paper proposes a new multi-parameter based scheduling (MPS) for downlink multi-user multiple-input multiple-output (MU-MIMO) system under space-time block coding (STBC) transmissions. Goal of this MPS scheme is to offer improved link level performance in terms of a low average bit error rate (BER), high packet delivery ratio (PDR) with improved resource utilization and service fairness among the user. This scheme allows the set of users to send data based on their channel quality and their demand rates. Simulation compares the MPS performance with other scheduling scheme such as fair scheduling (FS), normalized priority scheduling (NPS) and threshold based fair scheduling (TFS). The results obtained prove that MPS has significant improvement in average BER performance with improved resource utilization and fairness as compared to the other scheduling scheme.

Multiple-input and multiple-output (MIMO) is one of the key component in wireless standards. Wireless standards exploit MIMO to enhance user experience by improving the data rate and reliability of the link. Multiple-input and multiple-output (MIMO) systems formed by multiple transmit and receive antennas can improve performance and increase capacity of wireless sensor networks. In this Paper, the performance of different detection algorithms for V-BLAST, the Zero forcing algorithm (ZF), Minimum mean square error (MMSE) algorithm and the Maximum a-Posteriori (MAP) algorithm have been simulated and their performances have been compared. under the assumption that the receiver has perfect knowledge about the channel state information (CSI). Convolutional code can be combined with the V-BLAST algorithm to improve its performance.

A mobile ad hoc network (MANET) is a collection of wireless mobile hosts (computers, PDAs etc.) connected by wireless links, forming a temporary network without any wireline infrastructure. The hosts are free to move randomly and organize themselves arbitrarily resulting in rapid and unpredictable topology changes, in addition to it the wireless link subjects the signal to unpredictable environmental changes and hence provides only limited bandwidth. Due to the dynamic nature of the network topology and restricted resources, routing in MANET is a challenging task. Finding and maintaining the routes for multicasting the data is still more challenging. In this paper we propose node transition probability based multicast routing algorithm (NTPMR) with coded route diversity technique to improve the packet delivery ratio for MANET. This algorithm uses multiple routes to transmit the data and code packet to all the members of the multicasting group. It is found that the proposed algorithm is most reliable in the sense that it uses only the best neighbors to transmit the data and also that it possesses self-healing nature that can overcome single route failure using 1 /spl times/ N diversity code. The proposed algorithm is simulated using GIoMoSIM and its packet delivery ratio (PDR) performance with respect to mobility, number of multicast members in a group, number of nodes in a terrain range are studied. To understand the effectiveness of this algorithm, the performance results of single path, double path without coding are also presented. From the results, it is found that the coded route diversity technique provides improved PDR.

An ad-hoc network is the cooperative engagement of a collection of mobile nodes without the required intervention of any centralized access point or existing infrastructure. A number of routing protocols have already been proposed for ad-hoc networks. In most of these protocols, routing tables and considerable routing overheads are used to achieve routing. This paper proposes an approach to eliminate the use of routing tables and to reduce the overhead significantly in order to achieve efficient routing. In this paper, we propose power aided zoning (PAZ) protocol. In which power zones are formed between the source and the destination during the route discovery phase. Only the nodes that are in the periphery of these zones participate in the data transfer between source and destination. Every node maintains two-dimensional array that indicates whether the node is enabled to route the data for a particular source or not. The algorithm is simulated using GloMoSim and the performance results are compared with DSR and AODV. The results indicate a considerable improvement in delay and control overhead performance.