The Simulations Study Of Optimal Equivalent Subchannel Algorithm For Powerline Communication System

Power lines, as a medium of broadband communication, have attracted increasingly attention. Its feature of widely distribution, convenient connections and large channel capacity, has made it an effective solution for broadband access. Due to the variety of low voltage distribution network noise (including impulse noise, narrowband interference and background noise), the transmitted signals suffered frequency fading, and the reflection and refraction between nodes in the network will introduce multi-path effects. OFDM (orthogonal frequency division multiplexing) has a strong ability against attenuation and interference. In low-voltage power line communication system, the introduction of OFDM technology can overcome the effect of power line channel multipath, time-varying and frequency selective fading; improve stability and reliability of data transmission. In addition, not every power line communication subchannel is good for transmitting data, some subchannels are good, and some are bad, this imbalance of subchannels will affect the efficiency of data transmission in the system. By adopting subchannel equivalent optimization, combined with adaptive bit and power allocation algorithm, it can save signaling, improve transmission efficiency. The specific study focused on the following aspects:(1) According to the imbalance of subchannel features,analysis the equivalent subchannel optimization model,adopting the optimization algorithm to optimize the subchannel,then combined with the bit and power allocation algorithm to achieve fast distribution of bit and power in the equivalent subchannel.(2) Using matlab to simulate and analyze the performance of adaptive bit and power allocation algorithm,aim at the certain extent number of the bit allocation,adopting the equivalent subchannel algorithm will get better performance in low-voltage power line communication system.