Wireless receiver with intermittent shut-off of RF circuits

• US 20080159439A1
• Filed: 12/27/2006
• Published: 07/03/2008
• Est. Priority Date: 12/27/2006
• Status: Active Grant

• Current Assignee: Sony Semiconductor Solutions Corporation (Sony Group Corp.)
• Original Assignee: Altair Semiconductor Ltd. (Sony Group Corp.)
• Inventors: Bitran, Yigal
• Granted Patent: US 7,881,252 B2
• Time in Patent Office: Days
• US Class Current: 375/316
• CPC Class Codes: H04W 4/18 Information format or content conversion, e.g. adaptation by the network of the transmitted or received information for the purpose of wireless delivery to users or terminals
• CPC Class Codes: H04W 52/0248 dependent on the time of the day, e.g. according to expected transmission activity
• CPC Class Codes: H04W 52/0274 by switching on or off the equipment or parts thereof
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A terminal for use in a wireless network includes a radio frequency (RF) receiver, which is configured to receive and downconvert a RF signal. The RF signal includes a sequence of downlink frames, each downlink frame including at least a map zone followed by a data zone. The map zone contains an indication of a time allocation in the data zone during which downlink data will be transmitted to the terminal. An analog/digital (A/D) converter converts the output signal from the RF receiver into a stream of digital samples. A digital processing circuit processes the digital samples so as to identify the time allocation and to recover the downlink data transmitted during the identified time allocation, while shutting down the RF receiver during at least one interval during the downlink frame that is outside the identified time allocation.

Claims

1. A terminal for use in a wireless network, the terminal comprising:

a radio frequency (RF) receiver, which is configured to receive and downconvert a RF signal so as to generate an output signal, the RF signal comprising a sequence of downlink frames, each downlink frame comprising at least a map zone followed by a data zone, the map zone containing an indication of a time allocation in the data zone during which downlink data will be transmitted to the terminal;

an analog/digital (A/D) converter, which is coupled to convert the output signal into a stream of digital samples; and

a digital processing circuit, which is coupled to process the digital samples so as to identify the time allocation, responsively to the indication in the map zone, and to recover the downlink data transmitted during the identified time allocation, while shutting down the RF receiver during at least one interval during the downlink frame that is outside the identified time allocation.

2. The terminal according to claim 1, wherein the digital processing circuit comprises:

a digital physical layer interface (PHY);

a medium access control (MAC) processor; and

a power controller, which is coupled to shut down at least one digital component of the terminal, in addition to the RF receiver, during the at least one interval, wherein the at least one digital component is selected from a group of components consisting of the A/D converter, the PHY, and the MAC processor.

3. The terminal according to claim 1, wherein the time allocation has a start time and an end time, and wherein the digital processing circuit is configured to shut down the RF receiver after receiving the indication in the map zone, and then to activate the RF receiver at a first time that precedes the start time of the time allocation by a first margin, and to shut down the RF receiver at a second time that follows the end time of the time allocation by a second margin.

4. The terminal according to claim 3, wherein the digital processing circuit is configured to process the digital samples during a first part of the downlink frame in order to determine one or more characteristics of a wireless channel over which the RF signal is received, and to determine the first and second margins responsively to the one or more characteristics.

5. The terminal according to claim 4, wherein the one or more characteristics comprise channel coherence characteristics, and wherein the first and second margins increase as a coherence of the wireless channel decreases.

6. The terminal according to claim 5, wherein the channel coherence characteristics comprise a temporal coherence and a bandwidth coherence.

7. The terminal according to claim 4, wherein the one or more characteristics comprise a signal/noise ratio (SNR) of the wireless channel, and wherein the first and second margins increase as the SNR of the wireless channel decreases.

8. The terminal according to claim 4, wherein the downlink frame comprises a preamble that precedes the map zone, and wherein the digital processing circuit is configured to process the digital samples during the preamble in order to determine the one or more characteristics of the wireless channel.

9. The terminal according to claim 1, wherein the digital processing circuit is configured to make a determination that no time has been allocated for transmission to the terminal during a given downlink frame, and to shut down the RF receiver through all of the data zone of the given downlink frame responsively to the determination.

10. The terminal according to claim 1, wherein the sequence of downlink frames is transmitted by a base station in accordance with an IEEE 802.16 standard.

11. A method for communication;

comprising;

receiving and downconverting a radio frequency (RF) signal using a RF receiver of a wireless terminal, so as to generate an output signal, the RF signal comprising a sequence of downlink frames, each downlink frame comprising at least a map zone followed by a data zone, the map zone containing an indication of a time allocation in the data zone during which downlink data will be transmitted to the wireless terminal;

converting the output signal into a stream of digital samples; and

processing the digital samples so as to identify the time allocation, responsively to the indication in the map zone, and to recover the downlink data transmitted during the identified time allocation, while shutting down the RF receiver during at least one interval during the downlink frame that is outside the identified time allocation.

12. The method according to claim 11, and comprising shutting down at least one digital component of the wireless terminal, in addition to the RF receiver, during the at least one interval, wherein the at least one digital component is selected from a group of components consisting of an analog/digital (A/D) converter, a digital physical layer interface (PHY), and a medium access control (MAC) processor.

13. The method according to claim 11, wherein the time allocation has a start time and an end time, and wherein shutting down the RF receiver comprises controlling the RF receiver so as to shut down the RF receiver after receiving the indication in the map zone, and then to activate the RF receiver at a first time that precedes the start time of the time allocation by a first margin, and to shut down the RF receiver at a second time that follows the end time of the time allocation by a second margin.

14. The method according to claim 13, wherein controlling the RF receiver comprises processing the digital samples during a first part of the downlink frame in order to determine one or more characteristics of a wireless channel over which the RF signal is received, and determining the first and second margins responsively to the one or more characteristics.

15. The method according to claim 14, wherein the one or more characteristics comprise channel coherence characteristics, and wherein the first and second margins increase as a coherence of the wireless channel decreases.

16. The method according to claim 15, wherein the channel coherence characteristics comprise a temporal coherence and a bandwidth coherence.

17. The method according to claim 14, wherein the one or more characteristics comprise a signal/noise ratio (SNR) of the wireless channel, and wherein the first and second margins increase as the SNR of the wireless channel decreases.

18. The method according to claim 14, wherein the downlink frame comprises a preamble that precedes the map zone, and wherein processing the digital samples comprises processing the digital samples during the preamble in order to determine the one or more characteristics of the wireless channel.

19. The method according to claim 11, wherein processing the digital samples comprises making a determination that no time has been allocated for transmission to the terminal during a given downlink frame, and shutting down the RF receiver through all of the data zone of the given downlink frame responsively to the determination.

20. The method according to claim 11, wherein the sequence of downlink frames is transmitted by a base station in accordance with an IEEE 802.16 standard.