Short-range wireless communication

• US 8,571,479 B2
• Filed: 10/19/2012
• Issued: 10/29/2013
• Est. Priority Date: 06/16/2008
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell World Trade Limited (Marvell Technology Group Limited)
• Inventors: Banerjea, Raja
• Primary Examiner(s): Alam, Fayyaz
• Assistant Examiner(s): Hanidu, Ganiyu A
• Application Number:
  US13/656,502
• Publication Number:
  US 20130045688A1
• Time in Patent Office: 375 Days
• Field of Search: 455/41.2, 455/522, 455/24, 455/453, 455/69, 455/126, 455/115.1, 455/67.11, 455/13.4, 370/335, 370/437, 370/338
• US Class Current: 455/41.2
• CPC Class Codes: H04W 52/245 taking into account received signal strength
• CPC Class Codes: H04W 52/38 TPC being performed in particular situations
• CPC Class Codes: H04W 52/383 power control in peer-to-peer links
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 76/14 Direct-mode setup

Abstract

The present specification describes techniques and apparatus that enable wireless devices to communicate effectively at short ranges. In one implementation, the transmit power of a transmitting device is reduced to permit a receiving device to demodulate a signal.

Claims

1. One or more computer-readable memory devices storing processor-executable instructions, that responsive to execution by a processor, implement a wireless communicator to:

transmit, via a transmitter, a link-setup request through a wireless network to a device, the link-setup request requesting a current transmit power of the device and transmitted at a lower-than-nominal power level of the transmitter effective to reduce saturation of a receiver of the device;

receive, via a receiver, a link-setup response through the wireless network from the device, the link-setup response indicating the current transmit power of the device and having been received at a received power;

determine, based on the received power at which of the link-setup response is received, a desired data-signal transmit power for the device; and

transmit, via the transmitter, an indication of the desired data-signal transmit power through the wireless network to the device.

2. The one or more computer-readable memory devices of claim 1, comprising additional processor-executable instructions, that responsive to execution by the processor, implement the wireless communicator to determine whether a data signal received through the wireless network from the device is received at a power level that is too high to permit maximum communicative throughput with the device.

3. The one or more computer-readable memory devices of claim 1, comprising additional processor-executable instructions, that responsive to execution by the processor, implement the wireless communicator to:

receive, via the receiver, a data signal through the wireless network from the device, the data signal being received at a received data-signal power and having a modulation;

determine whether the data signal has a less-than-maximum throughput for the modulation;

determine, responsive to determining that the data signal has the less-than-maximum throughput and based on the received data-signal power, a second desired data-signal transmit power; and

transmit, via the transmitter, an indication of the second desired data-signal transmit power through the network to the device.

4. The one or more computer-readable memory devices of claim 3, wherein transmitting the indication of the second desired data-signal transmit power to the device comprises using a directed probe response frame.

5. The one or more computer-readable memory devices of claim 3, comprising additional processor-executable instructions, that responsive to execution by the processor, implement the wireless communicator to maintain a communication link through which the data signal is communicated.

6. The one or more computer-readable memory devices of claim 5, comprising additional processor-executable instructions, that responsive to execution by the processor, implement the wireless communicator to change, in response to a change in the received data-signal power, a transmit power at which communications with the device are transmitted to maintain the communication link.

7. The one or more computer-readable memory devices of claim 5, comprising additional processor-executable instructions, that responsive to execution by the processor, implement the wireless communicator to periodically re-determine whether the data signal has a less-than-maximum throughput for the modulation.

8. The one or more computer-readable memory devices of claim 1, wherein transmitting the link-setup request and transmitting the desired data-signal transmit power are performed using a direct-sequence spread spectrum (DSSS) modulation scheme.

9. The one or more computer-readable memory devices of claim 1, wherein transmitting the indication of the desired data-signal transmit power to the device is effective to cause the device to alter the current transmit power of the device.

10. A System-on-Chip (SoC) comprising:

a hardware interface to a receiver, the receiver configured to receive data via a wireless medium;

a hardware interface to a transmitter, the transmitter configured to transmit data via the wireless medium; and

one or more processors configured to execute processor-executable instructions that, responsive to execution, implement a wireless communicator;

transmit, via the transmitter, a link-setup request through the wireless medium to a device, the link-setup request requesting a current transmit power of the device and transmitted at a lower-than-nominal power level of the transmitter effective to reduce saturation of a receiver of the device;

receive, via the receiver, a link-setup response through the wireless medium from the device, the link-setup response indicating the current transmit power of the device and having been received at a received power;

determine, based on the current transmit power of the device and the received power at which of the link-setup response is received, a desired data-signal transmit power for the device; and

transmit, via the transmitter, an indication of the desired data-signal transmit power through the wireless medium to the device.

11. The SoC of claim 10, wherein the received power at which the link-setup response is received is indicated by a received signal strength indication (RSSI) associated with a communication link with the device.

12. The SoC of claim 10, wherein the wireless medium is associated with a wireless personal area network following an IEEE 802.11-2007 communication protocol.

13. The SoC of claim 12, wherein transmitting the link-setup request and transmitting the indication of the desired data-signal transmit power are performed using a direct-sequence spread spectrum (DSSS) modulation scheme.

14. The SoC of claim 10, wherein the wireless communicator is further implemented to:

receive, via the receiver, a data signal through the wireless medium from the device, the data signal having been received at a received data-signal power and having a particular modulation;

determine whether the data signal has a less-than-maximum throughput for the particular modulation;

determine, responsive to determining that the data signal has the less-than maximum throughput and based on the received data-signal power, a second desired data-signal transmit power; and

transmit, via the transmitter, an indication of the second desired data-signal transmit power through the wireless medium to the device.

15. The SoC of claim 10, the particular modulation of the data signal received from the device is an orthogonal frequency division multiplex (OFDM) modulation or a complimentary code keying (CCK) modulation.

16. A wireless-communication-capable device comprising:

a receiver configured to receive data via a wireless network;

a transmitter configured to transmit data via the wireless network; and

a wireless communicator configured to;

receive, via the receiver, a link-setup request through the wireless network from another wireless-communication-capable device, the link-setup request;

requesting a current transmit power of the transmitter;

modulated using a first modulation scheme; and

received at a power level insufficient to saturate the receiver;

transmit, via the transmitter, a link-setup response through the wireless network to the other wireless-communication-capable device, the link-setup response;

indicating the current transmit power of the transmitter; and

modulated using the first modulation scheme;

receive, via the receiver and in response to the link-setup response, an indication of a desired data-signal transmit power through the wireless network from the other wireless-communication-capable device, the indication of a desired data-signal transmit power;

indicating a desired transmit power at which data-signals modulated using a second modulation scheme are to be transmitted; and

modulated using the first modulation scheme; and

transmit, via the transmitter, the data signals modulated using the second modulation scheme and through the wireless network to the other wireless-communication-capable device, the data signals transmitted at the desired data-signal transmit power.

17. The wireless-communication-capable device of claim 16, wherein the first modulation scheme is a direct-sequence spread spectrum (DSSS) modulation scheme.

18. The wireless-communication-capable device of claim 16, wherein the second modulation scheme is an orthogonal frequency division multiplex (OFDM) modulation scheme or a complimentary code keying (CCK) modulation.

19. The wireless-communication-capable device of claim 16, wherein a distance between the wireless-communication-capable device and the other wireless-communication-capable device is about 0.2 meters or less.

20. The wireless-communication-capable device of claim 16, wherein the wireless network is a wireless personal area network following a short-range radio communication protocol.