Abstract:
Outdoor power line communications (PLC) systems represent an additional and
alternative for classical and communications. In this dissertation an analytical model
of Direct Sequence CDMA power line communications systems has been developed
for frequency-selective fading channel based on .the concepts of wireless
communication. Binary phase shift keying (BPSK) modulation scheme is considered.
The fading in power line is considered to follow Rayleigh distribution. During the
analysis it is considered that power line channel can carry frequencies from I to 21.48
MHz (bandwidth occupation 20.48 MHz) and the chip rate would be 10.24 Mchips/s
for DS-CDMA. The current research of power line channel modeling has been
concentrated on home automation, broadband indoor communications and broadband
data transfer in a low voltage distribution network between home and transformer
station. A frequency selective multipath channel is modeled whose path gain is found
to be Rayleigh distributed. A noise term has been introduced in the developed model,
which consists of all type of noises in power line. To estimate impulse noises the
statistical probability density functions have been used.
On the basis of the analytical model, the performance of the DS-CDMA technique has
been evaluated. The impact of power line noise and multipath propagation on signal
to interference ratio (SIR) and bit error rate (BER) are then analyzed under various
conditions. The performance parameters are evaluated as a function of number of
simultaneous users.PLC with DS-CDMA is found to be a promising option for future
telecommunication in a LAN and MAN.
