Comprehensive time-frequency-spatial spectrum measurement and analysis of TV band in Beijing

To understand the usage of TV spectrum, a comprehensive measurement is conducted in Beijing, China. The measurement consists of two parts, i.e., fixed measurement and radio environment mapping (REM). In the fixed measurement, spectrum utilization is calculated considering not only time domain utilization but also specific Chinese TV standards. Thus the spectrum utilization is 7% higher than reported previously. To study the geographical distribution of signal strength, REM is constructed for a small area in the downtown. Since traditional systematic sampling may place sample positions in inaccessible areas, a novel sampling algorithm named simulated annealing assisted electron repulsion (SAER) is proposed. Results show SAER results in smaller error in REM than systematic sampling and signal strength variation can reach 30 dB in the considered area, which means spatial spectrum access opportunities may exist for cognitive radio.