Research And Implementation Of Peer To Peer (P2P) Wireless Transceiver Baseband Algorithms

P2P network can fufil the requirements of the future customers, so it becomes the developmental trend for the communication society. P2P mobile terminal is the facility directly facing the users. It offers straight operation experience to them and influences their feelings to the network. Hence, terminal is important to both of the network and users. Terminal communication technique sustains and determines the development and process of mobile terminal. Consequently, it is necessary to investigate on mobile terminal transceiver integrated chips. The channel is time variant when the velocity of the terminal is high. Moreover, the radio frequency (RF) front end also generates frequency offset and phase noise. These factors will introduce intercarrier interference and seriously degrade the performance of the system. The traditional channel estimation methods designed for Wireless Local Area Network (WLAN) cannot be directly adopted in the P2P transceiver baseband, so it is necessary to build a novel channel estimation and ICI cancellation method for the target system. Research papers based on P2P transceiver integrated chips are still unavailable in our country at present, so the research for the implementation of P2P baseband algorithms can be the theoretical foundation for this field. Through the hardware implementation, we can test the receiver algorithms and evaluate the resources and power consumption in the real environment; we also can do the cross layer experiment associated with media control access (MAC) layer and physical layer. So, it is obvious that the research for the implementation of P2P baseband algorithms is quite necessay and urgent.Firstly, the physical layer structure of the P2P wireless transceiver is investigated. Under the constraints of communication distance, mobile velocity and power consumption etc, the physical layer SPEC is deduced. Then, the reconfigurable RF front end and baseband processor are designed. System level simulation results show that the proposed physical layer structure can fufil the requirements of the SPEC.Secondly, a computationally efficient channel estimation and ICI mitigation method is investigated. It uses both the pilots and training sequences for estimation. Compared with the traditional algorithms, the proposed method can perform better in the mobile environment. Based on the Yuler-Walker equation, the parameter of the auto regressive (AR) model can be found. However, in a real scenario, the channel characteristics are not perfectly known. When the normalized frequency offset is less than 10^-2, the parameter of the AR model can be approximated as one. The state space model is modified based on the above assumption and the Kalman filter algorithm is simplified. Simulation results reveal that the performance of the proposed method is better than the traditional ones at a much lower complexity. Thirdly, this paper puts forward a novel ICI self-cancellation method based on orthogonal matrix mapping. The traditional methods are sensitive to the multi-path delay spread and not compatible with the original system. To deal with them, the paper develops four methods in time domain, which maps one data symbol into two symbols with equal and symmetric subcarrier indexes respectively. Simulation results show that the proposed methods improve the carrier to noise ratio (CIR) performance. They yield a better bit error rate (BER) performance of 5dB compared with the traditional methods in multi-path channels with a much lower peak to average power ratio (PAPR). Moreover, the proposed methods are backward compatible with the original system.Then, a high performance and low complexity adaptive modulation method is investigated. It consists of two steps. The first one is the signal to noise (SNR) estimation algorithm, and the other is the adaptive parameter design scheme. The traditional SNR estimation methods often perform well in additive white Gaussian noise (AWGN) channel. However, their performance may degrade dramatically in a multi-path channel. To deal with it, a novel SNR estimation method is proposed. Generally, the void subcarriers are inserted into the symbol for spectrum shaping. These subcarriers are used for SNR estimation in this work. Then, the received data is used to estimate the energy of the transmitted data and noise. Simulation results show that the proposed method is not sensitive to Doppler shift and multi-path delay spread. The proposed method yields a 93.3% improvement of bit error rate compared with the existing algorithms at a much lower complexity. The bandwidth efficiency can increase 347% with the proposed adaptive modulation method.These algorithms are synthesized on field programmable gate array (FPGA). The experimental results show that the proposed methods not only perform well, but also have the realistic advantages of small area and low power consumpation.Finally, the implementation of P2P wireless transceiver baseband algorithms is investigated. There are many references on algorithms research. However, few of them discuss the occupied resources and power consumption in the system when the algorithms are implemented. This paper supplies a gap to this field. First, an optimized clock strategy is introduced. Through the analysis of the key modules, that is, the FFT and Viterbi decoder, it is concluded that these modules have the advantages of low cost, low power consumption and high efficiency. Synthetical results show that the P2P baseband algorithms could fufil the requirements of the wireless transceiver.