A novel method for throughput enhancement of adaptive OFDM in attenuated power line channels

Abstract

Communications over power line channels offer inexpensive and convenient solution for signal transmission; however power line channel suffers from multi path fading and frequency selectivity along with manmade burst impulsive noise.Data spread OFDM has been evolved as an efficient adaptive modulation that controls the power of each subcarrier according to its channel transfer function. This paper aims to present a novel method using data spread OFDM to achieve higher carrier to noise ratio (CNR) and lower bit error rate (BER) in highly attenuated power line channel conditions. The simulations prove that the proposed system outperforms the conventional one under harsh power line conditions. Keywords-bit loading, impulsive noise, data spread OFDM, power line communication, throughput. l. INTRODUCTIONThe Power line Channel is drawing a great interest nowadays for its capability of transmission of high data rates without the need for new cables depending upon existing wiring system. Broad band communications over power line can offer many services like internet appliance connectivity, Home PC Networking, Multimedia streaming access, on the contrary the power line channel exhibits mUltipaths caused by reflections on the discontinuities of network leading to high attenuation performance for power line signal over certain frequencies, also the power line channel suffers from many kinds of noise such as: background colored noise, narrow band noise and impulsive noise. These harsh conditions limit the good performance for the transmitted signal over power line channels.OFDM has been considered as robust adaptive modulation scheme that has many advantages among other modulation types such as: low complexity, channel equalization, good resistance to narrowband and impulsive noises, and the ability to achieve approximate value of Shannon limit for channel capacity using simple coding techniques. Data spread OFDM was introduced in [1 ][2] [3] where an efficient bit loading algorithm is adopted to manage the power of each sub carrier according to its channel situation, however the data spread OFDM is exposed to high performance degradation in case of high attenuation performance of power line channel especially

Optimised resource allocation under impulsive noise in power line communications

“…Orthogonal frequency division multiplexing (OFDM) has been considered as robust adaptive modulation scheme that has many advantages over other modulation types such as low complexity, channel equalisation, good resistance over narrowband and impulsive noises and the ability to achieve approximate value of Shannon limit for channel capacity using simple coding techniques [3]. However, the data spread OFDM suffers degradation due to varying and frequency selective attenuation in the channel.…”