基于 Matlab 的 OFDM 系统信道评估设计
CHANNEL EVALUATION DESIGN OF OFDM SYSTEM
BASED ON MATLAB
ABSTRACT
The research background of this paper is based on the development of CMTS product based
on DOCSIS3.1.In the 2015 ICTC conference report, a speech named "welcome to DOCSIS3.1"
announced the arrival of DOCSIS3.1. DOCSIS3.1 is next generation access technology used by
CMTS devices which widely accepted by the international. It uses the latest technology in
physical layer technology in recent years, such as OFDM, OFDMA, LDPC encoding and
decoding, which greatly improves the signal transmission rate on coaxial cable. OFDM
(orthogonal frequency division multiplexing) is a kind of efficient sp ecial multi carrier
modulation technology which can resist the multipath propagation effectively, and it has strong
anti-jamming performance. This technology has obtained widespread application in the field of
mobile communication, digital TV and digital broadcasting.
In the development and deployment of CMTS, it is an urgent need problem that how to
optimize and adjust the transmission parameters according to the channel characteristics of
different users or segment. So this paper will analyze the architecture of OFDM which is used in
CMTS system, and design new algorithm to analyze the signal before it has been demodulated in
receiving end. Specifically speaking, we will carry out channel evaluation by means of MER
(modulation error ratio). MER can represent a single "quality factor" of the received signal, which
is often used as an early indication of the receiver's signal can be correctly decoded. Generally
speaking, when we calculate the MER, we need to known the received signal and transmitted
signal. But the transmitted signal is often unknown due to various reasons in the actual situation.
So this paper will mainly studies how to detect the blind MER in receiving terminal in the case of
unknown transmitted signal and use the value of MER to evaluate the channel. In order to create a
more friendly user interface, the paper will allow the user to carry out MER detection in receiving
terminal based on arbitrary segments and arbitrary size of received data. In the end, this paper will
do the large data analysis on the results of several calculations including the determination of
