Hinoc Key Unit Baseband Algorithm Design

This paper mainly studied the HiNOC system baseband transceiver system. Because HiNOC system using OFDM technique, the OFDM synchronization algorithm of receiver was focused on. The algorithms of receiver witch are suitable for HiNOC system were designed in the condition of the HiNOC signal and cable channel. First of all, the paper introduced HiNOC technique and OFDM technique, including their origin and development, as well as their advantages and disadvantages. Then the principle of OFDM system and its realization method were introduced and mathematically deduced. The HiNOC system’s physical layer structure and the simulation environment were introduced, making easier for studying of reader. Next, the algorithms of receiver witch included synchronization, channel estimation and equalization, as well as the phase noise elimination algorithms were researched. And the novel algorithms of frame synchronization, fractional carrier synchronization, integral carrier synchronization, channel estimation and phase noise elimination were introduced and simulated.Performance of the algorithm can be seen from the simulation. The MMSE was used in coarse symbol synchronization and has good performance, so there is no improvement in this paper. The MMSE was also used in frame synchronization as fine synchronization, and became a novel algorithm by some improvement. Because this algorithm can be unaffected by carrier frequency offset and can ensure complete synchronization, so carrier synchronization algorithm was completely unaffected by coarse synchronization error. The two order loop and the judge-lock method were used for fractional carrier synchronization.By this algorithm, residual frequency offset can decrease with time and locked in a small range(The normalized residual frequency offset was less than1/10000in simulation) in a short period of time(In general was less than0.1in simulation). This algorithm had good performance even for high order modulation signal. There were some difficulties about integral carrier synchronization that the HiNOC signal did not have pilot and the subcarrier spacing of preamble and data were inconsistent. By conquering there difficulties, the novel algorithm can achieve completely accurate synchronization. On the base of LS criterion and the two order interpolation algorithm, there is an additional pretreatment for preamble(not required for pilot or two stage continuous preamble) and first order correction filter in channel estimation, and this algorithm had similar performance with the ideal channel estimation. Two novel algorithm about the ICI of phase noise were introduced. Although the performance was merely close to the existing algorithm, new thought for phase noise elimination was suggested.