Study On Power Control Of Coded Cooperation Based On Cooperative Diversity Of CDMA Wireless Network

With the development of wireless communication, should have more data rates and QoS. To further improve the communication quality and expand channel capacity of the new technology is academic circles both home and abroad, industry issues of common concern. Channel coding is to ensure a good communication quality of communications technology. However, in poor channel state, the quality of communication difficult to ensure. Existing MIMO (Multiple-Input Multiple-Output) have maked full use of airspace's resources to increase channel capacity. But the mobile terminal to the size, quality and power consumption requirements is not easy to install multi-antenna, MIMO technology is hard to achieve in wireless sensor network. Sendonar et al advance a new diversity of the airspace--cooperation diversity. It enables single antenna mobiles share their antennas and generate a virtual multi-antenna transmitter that allows them to achieve transmit diversity. However, cooperative diversity compared to traditional direct communication, cooperative diversity is not only the source to send the information needs of power, and relay help the source node to transmit information also needs to consume power. so, it's the key issues how to maximize power efficiency and minimize inter-node interference in cooperation diversity.At present, the cooperation diversity technology have more results in TDMA and FDMA, because it's easy to analysis their system model and performance. CDMA have huge system capacity, and high spectral efficiency, inherent ability of anti-multipath characteristics, and become the most important multiple access technology. As well as in the wireless cellular network, such as wireless sensor network is widely used. But in the CDMA wierless network, nodes use the same frequency band, and between the spreading codes have relevant non-ideal characteristics that caused mutual nodes interference. This not limited system capacity, but will brought near-far effect who seriously affect the communication. To further improve the performance of wireless networks,In this paper, combined channel coding, cooperation diversity and power control to start an in-depth research in CDMA wireless networks.Main content of this thesis:Charter 1 introduces the concept, separation and advantages of cooperative diversity, gives the research situation on cooperative diversity of CDMA wireless network home and abroad, and analyzes the significance of applying channel coding cooperative diversity and power control in CDMA Wireless Network. Finally exemplify the research purpose and content.Charter 2 introduces the basic knowledge about the wireless channel fading type, a few kinds of traditional diversity technology and the combined method of diversity. Then we introduce the system model of cooperative diversity and the time division channel allocation plan. The paper focuses on: Fixed Amplify-and-Forward, Fixed Decoded-and-Forward, Selective Decoded-and-Forward and Incremental Amplify-and-Forward, which are based on TDMA system. The paper analyzes the approximate expression and diversity order of broken probability of various protocols, compares the performance of protocols and explains the methodology analysis of broken probability and imitation results of protocols. Except Fixed Decoded-and-Forward protocol, the other three protocols can provide two degree complete diversity increase. The simulation results of the diversity order embodies that there exist a balance diversity order and normalized spectrum efficiency.Charter 3 proposes a Decoded-and-Forward protocol of CDMA wireless network cooperative diversity based on two codes and establishes the system model of the protocol. According to the analysis, for the partner chosen in this system, the paper analyzes the average error rate and diversity order in fade environment and fading environment. Under the condition of meeting power limitation, not using extra spread frequency code resources and not affecting other codes communication, the methodology analysis of the average error rate and the simulation results indicate that under the same SINR the cooperative diversity lows the average error rate. Meanwhile, the analysis of diversity order indicates that this system can gain the complete diversity gain.Charter 4 proposes power allocation scheme of CDMA wireless network Decoded-and-Forward cooperative diversity and establishes the system model. First, make imitation to the average error rate and get the average error rate under the diversity as well as the situation in non-diversity, and compared the average error rate on the base of adopted power allocation and the average error rate under the average power. Second, the methodology analysis and imitation results indicate that under the condition of not using extra spread frequency code resources and not affecting other nodes communication, compared with the same SNR and the same power cooperative transmission, power control obviously lows the average rate of source nodes. Meanwhile, the imitation analysis of two users under the same communication channel and the same power allocation, the need of total power greatly decreases than before.Charter 5 proposes double relay coding cooperative diversity and the power control of relay coding cooperative diversity based on the source with two nodes and establish the systemic model of protocol. The paper analyzes the average error rate performance under the fading and faded circumstances. Methodology analysis and imitation results indicate that under the condition of not using extra spread frequency code resources and not affecting other nodes communication, compared with the same SNR and the same power cooperative transmission, power control obviously lows the average rate of source nodes. Meanwhile, the imitation analysis of three users under the same communication channel and the same power allocation, the need of total power greatly decreases than before.Charter 6 summarizes the whole research work and does the further expectation of research.The innovation of this paper is following: 1. Propose CDMA wireless network channel coding cooperative diversity protocol and establishes a system model of the protocol, and get the expressions of the average error rate and diversity order of protocol under the fading environment and low fading environment.2. Propose the power control of CDMA wireless network cooperative diversity protocol with single node, establish a system model and conduct the allocation scheme in non-frequency selective fading environment.3. Propose the two-relay node cooperative diversity protocol and the power control of the two-relay node cooperative diversity, establish a system model and the expressions of the average error rate and diversity order of protocol under the fading environment and low fading environment as well as the allocation scheme in non-frequency selective fading environment.