Coding efficiency and bandwidth enhancement in polar delta sigma modulator transmitter

TLDR: This paper introduces an architecture to enhance coding efficiency (CE) and bandwidth of the delta sigma modulator transmitters using a low pass envelope delta s Sigma modulator (LPEDSM) to reduce the quantization noise and to improve the CE.

Abstract: This paper introduces an architecture to enhance coding efficiency (CE) and bandwidth of the delta sigma modulator transmitters. In this architecture a low pass envelope delta sigma modulator (LPEDSM) is used instead of traditional cartesian low pass delta sigma modulator (LPDSM) to reduce the quantization noise and to improve the CE. Simulation results show that for an Uplink long term evolution (LTE) signal with 1.4 MHz bandwidth, 7.8-dB peak to average power ratio (PAPR), and an oversampling ratio (OSR) of 32, the CE for the polar LPEDSM transmitter is equal to 42 % in compare to 9.7 % CE for cartesian LPDSM transmitter. In the next step, a quantization noise reduction loop with in-band quantization noise filtering are implemented in this architecture. By using this combined technique for an Uplink LTE signal with 1.4 MHz bandwidth, with the same PAPR and OSR of 32, the CE is improved from 42 to 59.33 % with 40 dB signal to noise and distortion ratio.