Survey of RF Communications and Sensing Convergence Research <s> D. SPREAD SPECTRUM METHODS <s> Linear frequency modulated (LFM) signals and the associated pulse compression techniques are attractive in applications where highly secure and robust communication is needed. This paper investigates the novel integration of radar and communications utilizing LFM waveforms. The simulations suggest that the performance of the communications-receiver deviates at most 2 dB from the theoretical probability of bit error for /spl pi//4-differential phase shift keying. The simulated radar receiver-operating characteristics for false-alarm probabilities between 10/sup -2/ and 10/sup -4/ also compares very well with the theoretical limits for a coherent system. <s> BIB001 </s> Survey of RF Communications and Sensing Convergence Research <s> D. SPREAD SPECTRUM METHODS <s> With the rapidly incremental demand in electronic devices, there is something in exploring multifunctional RF systems for reducing cost, minimizing the radar cross and probability of intercept, etc. This paper presents an integration system of radar and communication based on DSSS (direct sequence spread spectrum) technique, an attractive technique which is highly secure and robust. It utilizes different PN code to spread the spectrum of radar and communication data to avoid jamming mutually. Additionally, it uses BPM to gain better performance. The simulation over an ideal AWGN channel shows that the system can work perfectly <s> BIB002 </s> Survey of RF Communications and Sensing Convergence Research <s> D. SPREAD SPECTRUM METHODS <s> Multiple-input multiple-output (MIMO) extensions to radar systems enable a number of advantages compared to traditional approaches. These advantages include improved angle estimation and target detection. In this paper, MIMO ground moving target indication (GMTI) radar is addressed. The concept of coherent MIMO radar is introduced. Comparisons are presented comparing MIMO GMTI and traditional radar performance. Simulations and theoretical bounds for MIMO GMTI angle estimation and minimum detectable velocity are presented. The simulations are evaluated in the time domain, enabling waveform design studies. For some applications, these results indicate significant potential improvements in clutter-mitigation SINR loss and reduction in angle-estimation error for slow-moving targets. <s> BIB003 </s> Survey of RF Communications and Sensing Convergence Research <s> D. SPREAD SPECTRUM METHODS <s> Radar and communication integrated system has been a development trend of technologies. To resolve existing problems of integrated systems, this paper presents a novel method of waveform design for radar and communication integrated system based on chirped spread spectrum (CSS) and proposes the structure of the integrated system. The advantage of this system is that different functions can be realized in a same platform but without jamming between each other. Performance analysis and simulation results show that the proposed system can be efficiently implemented and meet practical demands. <s> BIB004
Similar to OFDM, spread spectrum waveforms have been proposed for their attractive, noise-like autocorrelation properties. Some work focused on orthogonal spreading codes between the radar and communications users employing direct-sequence spread spectrum (DSSS) BIB002 , while others looked at chirped spread spectrum (CSS) to avoid jamming between the two users BIB004 , BIB001 . Ultimately, the performance of these systems is limited by the degree of orthogonality that can be obtained in the joint system, theoretically limited to the inverse of the time bandwidth product BIB003 .