Research On Anti-collision Algorithm Of Wireless USB

Wireless USB technology, a kind of high speed Wireless Personal Area Network Communication Technology, combines UWB technology with USB technology. It occupies a very wide frequency band. When it coexists with other communication systems, spectrum overlap is unavoidable and an conflict may occur. Such conflict has become the technical bottleneck that hinders the development of Wireless USB technology.Reducing Wireless USB transmit power not only fails to completely solve the conflict problem, but also weakens system reliability and shortens transmission distance. Interference conception and avoidance technology is the latest research, which is the application of cognitive radio technology in UWB. First, it detects and analyzes the radio environment, and adjusts parameters adaptively. Then, it uses the intermittent or spectrum holes to communicate. In this paper, the Wireless USB anti-collision algorithm based on interference perception and avoidance technology is investigated.In the area of interference perception, Wireless USB's transmission signal has the characteristic of low power spectrum density, which is much lower than that of narrow band system. The symbol energy of Wireless USB's received signal after OFDM demodulation, in fact reflects the power status of each frequency band. In this paper, based on the power detection technology, a full frequency-domain interference sensing algorithm that uses symbol energy detection method is proposed. The theoretical analysis and simulation both show that the symbol energy detection algorithm can perceive the entire frequency domain and is of low complexity and high flexibility; and because the power of the narrowband signal is 10dB greater than that of the Wireless USB system signal, the proposed algorithm can accurately sense the presence of narrowband systems and estimate the frequency band.In the area of avoiding the interference, we can achieve the best frequency inhibition performance by combining invalid subcarriers technology with subcarrier sideband suppression technology in frequency domain. This paper introduces improved low complexity positive interference avoidance algorithm, which achieves greater depth of suppression by modifying some sub-carrier data and eliminating the side lobe at interference position. The simulation shows that using low complexity positive interference avoidance algorithm can reach the suppression depth of over -35dB.In addition, the spectrum reshaping may result in some loss of information of sub-carriers and lower system reliability. So far, there has not been any report researching on this issue. To solve this problem, the concept of orthogonal array is introduced and the orthogonal expansion mixed algorithm is proposed in this paper. Before OFDM modulation of transmitter, the algorithm can distribute the signal of every frequency domain to a group of sub-carriers by using high rotation matrix expansion, and can also distribute the attenuation evenly to each channel by using subcarrier interleaving technology. Consequently, the problem that system reliability is lowered by spectrum reshaping can be solved. The simulated result indicates that this algorithm can lower the system bit error rate by 1~2 orders of magnitude with the presence of multiple narrowband interference, and significantly strengthens the system reliability and anti-interference capability.