Study And Design On The Optimum Control Of Data Throughput Based On Cross-Layer In Wireless Network

In wireless communication networks, the demand for high data rates and quality of service (QoS) is growing at a rapid pace. However, the performance of wireless links is severely degraded due to channel fading, which limits the overall system throughput considerably relative to wired-line alternatives. Throughput, defined as the data rate successfully received, is a key measure of quality of service (QoS) for wireless data transmission systems. To enhance throughput in future wireless data communication systems, adaptive modulation and coding (AMC) at the physical layer and automatic repeat request (ARQ) protocol at the data link layer have been studied extensively, while they also have many obvious defects in aspects of complexity, overall performance, energy consumption and so on.At first, this paper has been proposed an exact and general closed-form expression of the BER performance for the Quadrature Amplitude odulation (QAM), under an AWGN channel when Gray code mapping is employed. And by simulation to verify its accuracy and the approximateSecond, Compared with the separated control of adaptive modulation and coding, and automatic re-transmission protocol on the layer, in this paper, based on the idea of cross-layer design, the cross-layer protocol of adaptive modulation and coding combined with automatic retransmission control under the best number of Separate sub-package is designed based on AMC at the physical layer and ARQ at the data link laye. The protocol with the receiver back to the transmitter SNR as the basis for tracking channel state conduct real-time control. And to maximize system throughput as the goal, the method is given to choose jointly the number of sub-packet and the class of modulation coding. Finally, to the cross-layer control protocol based on comprehensive consideration of system parameters and data load on the impact of energy consumption, a mathematical model of a wireless sensor network based on the data per-bits energy equivalent is established in this paper. And through simulation, analysis and research the data throughput in the process of maximizing the effectiveness of transferring data on the impact of energy consumption.