Power-saving apparatus used for wireless communication receiver and system, and method using the same

A power-saving transceiver for wireless communication system, comprising:

• an antenna, for receiving and transmitting a Radio Frequency (RF) signal;
• an antenna switch, electrically connected to the antenna and a transmitter;
• a zero-Intermediate-Frequency (zero-IF) RF receiver, electrically connected to the antenna switch, for providing a first signal and a second signal according to the RF signal received from the antenna;
• a baseband demodulator, electrically connected to the zero-IF RF receiver, for providing a third control signal to the zero-IF RF receiver and a demodulated signal according to the first signal and the second signal;
• and
• wherein the baseband demodulator comprises:
• a first configurable N-bit ADC, for providing a first N-bit signal according to the first signal and a first control signal;
• a second configurable N-bit ADC, for providing a second N-bit signal according to the second signal and a second control signal;
• a receive signal strength indicator (RSSI) and automatic gain control (AGC) unit, electrically connected to the first configurable N-bit ADC and the second configurable N-bit ADC, for providing the first control signal, the second control signal and a third control signal according to an estimated received signal strength (PR);
• and
• a baseband demodulator processor, electrically connected to the first configurable N-bit ADC and the second configurable N-bit ADC, for processing the first N-bit signal and the second N-bit signal and outputting a demodulated signal.

A method for saving power in a wireless communication receiver, comprising steps of:

• receiving a Radio Frequency (RF) signal from an antenna to a zero-Intermediate-Frequency (zero-IF) RF receiver according to an antenna switch;
• estimating an estimated received signal strength (PR) of the RF signal from a receive signal strength indicator (RSSI) and automatic gain control (AGC) unit located in a baseband demodulator;
• comparing the estimated received signal strength (PR) with a receive signal strength indicator thresholds value (RSSITH) to generate a first control signal and a second control signal;
• providing a third control signal based on the estimated received signal strength (PR), with the first control signal to control a first configurable N-bit analog-to-digital converter (ADC) in the baseband demodulator and the second control signal to control a second configurable N-bit ADC in the baseband demodulator, and the third control signals consisting of an ON/OFF states of a first stage of low noise amplifiers (LNA) and a second stage of low noise amplifiers (LNA), a gain of a first plurality of variable gain amplifiers (VGAs) and a gain of a second plurality of variable gain amplifiers (VGAs).