Cross detection method and its improved effect in BER for DAB diversity receiver

Broadcasting receivers with receiving function for digital radio service have been developed recently in the world. Especially in these receivers, DAB is widely deployed as digital radio broadcasting standards in many countries caused by the simplified digital demodulation architecture on receiver equipment. Though in DAB system, DQPSK is specified as modulation scheme, it has a general problem of deteriorating symbol error rate compared to that of synchronous detection. This is caused that demodulation method for DQPSK must be operated by using both noised received signal and noised delayed signal. Therefore, we propose a new noise reduction method using space diversity for decreasing noise effect. This method generates criterion symbol simply by referring some received signals in each antenna element, and also calculate phase difference between received signal and past received signal on another antenna element with depending on the phase shift of criterion symbol. Then DAB diversity receiver can obtain the advantageous effect in BER improvement effect by combining both conventional detected signals and additional generated signals as mentioned above. In this paper, we show that our proposal scheme can achieve the improved effect of required E_b/N₀ of 0.2-0.5 dB on BER=10^-3, in spite of simple additional receiver equipment.