Provided is an ARTM CPM demodulation and synchronization method with low implementation complexity. The method comprises, firstly, performing a two-stage delay on a received signal to obtain three branch signals; then performing mixing, low-pass filtering, matched filtering and phase compensation processes on the three branch signals, and performing Viterbi demodulation processing on the I-branch signal, and then calculating a timing error and a carrier phase error using a demodulation processing result; and finally, adjusting a code NCO and a carrier NCO by using a filtering result of the timing error and the carrier phase error, so as to achieve symbol timing synchronization and carrier phase synchronization. Compared with the existing optimal demodulator, the method of the present invention has less loss of bit error performance, and the numbers of matched filters and states required for demodulation are greatly reduced, thereby the demodulation complexity can be greatly reduced and the system stability can be effectively improved.

ARTM CPM demodulation and synchronization method with low implementation complexity

The invention discloses a symbol timing synchronization method of visible light communication. The problem that the resource is wasted since the multi-peak, the timing synchronization position swinging and too-long time use in accurate timing position determination are existent in the prior art is mainly solved. The realization step is as follows: 1, establishing a channel model; 2, computing a mobile related value Z; 3, computing a dynamic threshold value; 4, comparing the mobile related value with the dynamic threshold value, if detecting that the mobile related value is greater than or equal to the dynamic threshold value at some moment, regarding the position at this time as the timing position of the symbol. By using the symbol timing synchronization method disclosed by the invention, the accurate positioning of the symbol can be realized, and the instantaneity is strong; the method disclosed by the invention has the advantage that the prior art cannot match especially under the low signal-to-noise ratio. The method has good application prospect in the visible light communication.

Symbol timing synchronization method of visible light communication

The invention provides a low complexity bit synchronization method for telemetry PCM/FM multi-symbol detection (MSD), comprising: firstly using the likelihood ratio of the MSD as the statistical variable of the timing estimation, and then directly using the timing synchronization loop in the traditional PCM/FM limiting frequency discrimination receiver to realize the bit synchronization. Comparedwith the traditional ''late-morning gate'' MSD bit synchronization method, the method provided by the invention saves a high complexity operation of the MSD branch, and greatly reduces storage and computing resources of the receiver. In addition, the invention adopts the Gardner algorithm as a timing error detecting unit, which is convenient for high speed implementation. The normalized variance of the timing estimation error of the method is still less than 0.01 in the low signal-to-noise ratio (SNR) region, which satisfies the requirements of the telemetry receiver, and the bit error rate (BER) performance has almost no loss compared to the ideal synchronization situation, thereby having good application prospects.

Low complexity bit synchronization method for PCM/FM multi-symbol detection

The invention discloses a multi-symbol detection method based on CPM signal, belonging to the field of continuous phase frequency shift keying signal demodulation. The method comprises the steps: 1, pre-processing the received signal to obtain the baseband complex signal component and generate a local detection sequence; 2, sliding the baseband complex signal component according to the packet length N in order and obtaining 2N maximum likelihood values and a maximum likelihood sequence by performing maximum likelihood calculation on the local detection sequence; 3, judging each symbol in the maximum likelihood sequence for N times and obtaining a preliminary demodulated signal; 4, carrying out peak detection on 2N maximum likelihood values to extract bit synchronization signal, and outputting final demodulated signals from that preliminary demodulated signal; The invention solves the problems of high computational complexity and low demodulation performance caused by improving bit error rate by increasing matching length. The performance of demodulation error rate is greatly improved and the complexity of signal demodulation is reduced.

A method for multi-symbol detection based on CPM signal

The invention relates to a CPM modulation digital realization method based on a table lookup method and a digital CPM modulation module. The method comprises the steps that (1) the instantaneous phase of a CPM baseband modulation signal is composed of two parts of a correlation phase and an accumulation phase, correlation phase information is stored in a phase table in advance, and the correlation phase of the signal is obtained by looking up the table; (2) an accumulator performs continuous accumulation of phase increment so that the accumulation phase is obtained; (3) the correlation phase and the accumulation phase are added so that the instantaneous phase of the CPM baseband modulation signal can be obtained; and (4) the CPM baseband modulation signal is obtained by looking up a sine table and a cosine table according to the phase information of the CPM modulation signal. According to the method, realization is easy, complexity is low and range of application is wide, and the established phase table is correlated with sampling time so that continuity of the CPM modulation phase can be guaranteed, and realization precision is high and thus use of coherent demodulation is facilitated for a receiver.

CPM modulation digital realization method based on table lookup method and digital CPM modulation module

The present invention relates to a CPM modulation digitization implementation method based on a table lookup method, and a digital CPM modulation module. The method comprises: (1) an instantaneous phase of a CPM baseband modulation signal being composed of two parts, namely, a correlation phase and an accumulation phase, pre-storing correlation phase information in a phase table, and obtaining the correlation phase of the signal by looking up the phase table; (2) an accumulator performing continuous accumulation on phase increments so as to obtain the accumulation phase; (3) adding the correlation phase and the accumulation phase, so that the instantaneous phase of the CPM baseband modulation signal can be obtained; and (4) obtaining the CPM baseband modulation signal by looking up a sine table and a cosine table according to the phase information about the CPM modulation signal. The method is simple in implementation, low in complexity and wide in suitable range, and the established phase table is associated with a sampling time, thereby ensuring the continuity of a CPM modulation phase, having a higher implementation precision and facilitating the adoption of coherent demodulation by a receiver.

Chen Ming

Papers

ARTM CPM demodulation and synchronization method with low implementation complexity

CPM modulation digital realization method based on table lookup method and digital CPM modulation module

Cpm modulation digitization implementation method based on table lookup method, and digital cpm modulation module