Co-existence of narrow-channel transmitter and wide-channel receiver

1. A communication device comprising:

a processor;

a receiver operable in wide channels in a radio frequency band;

a first antenna coupled to the receiver;

a transmitter coupled to the processor, the transmitter operable in narrow channels in the radio frequency band, the processor implementing a frequency hopping spread-spectrum technique among those of the narrow channels marked in a channel map as available and excluding those of the narrow channels marked in the channel map as unavailable;

a second antenna coupled to the transmitter; and

non-volatile memory storing adjacent channel rejection ‘ACR’ information that characterizes tolerance of the receiver to adjacent channel interference ‘ACI’ caused by transmissions from the transmitter through the second antenna,

wherein in the event of reception by the receiver of signals over one of the wide channels, the communication device is to mark in the channel map as unavailable one or more of the narrow channels outside the one of the wide channels, based on the ACR information, on the transmit power of the transmitter, and on the strength of the signals as received by the receiver on the one of the wide channels.

2. The communication device as claimed in claim 1 , wherein the radio frequency band is in the unlicensed industrial, scientific and medical ‘ISM’ 2.4 GHz band.

3. The communication device as claimed in claim 2 , wherein the receiver is a wireless local area network ‘WLAN’ receiver and a width of the wide channels equals 23 MHz.

4. The communication device as claimed in claim 2 , wherein the transmitter is a wireless personal area network ‘WPAN’ transmitter and a width of the narrow channels equals 1 MHz.

5. The communication device as claimed in claim 1 , wherein the frequency hopping spread-spectrum technique is an adaptive frequency hopping spread-spectrum technique.

6. The communication device as claimed in claim 1 , wherein the processor has access to the ACR information.

7. The communication device as claimed in claim 1 , the ACR information comprising for a particular one of the narrow channels a maximum ratio of transmission power level to received signal strength indicator ‘RSSI’ value at which a signal received on the one of the wide channels in the presence of interference from the transmitter transmitting on the particular one of the narrow channels will be decoded correctly.

8. The communication device as claimed in claim 1 , the ACR information comprising for a particular one of the narrow channels a maximum ratio of transmission power level to received signal strength indicator ‘RSSI’ value at which a signal received on the one of the wide channels in the presence of interference from the transmitter transmitting on the particular one of the narrow channels will be decoded correctly, wherein the particular one of the narrow channels is marked in the channel map as unavailable where the ratio of the transmit power level of the transmitter to the strength is greater than the maximum ratio.

9. The communication device as claimed in claim 1 , further comprising:

a transmitter coupled to the first antenna and able to operate in the wide channels.

10. The communication device as claimed in claim 1 , further comprising:

a receiver coupled to the second antenna and able to operate in the narrow channels.

11. A co-existence method comprising:

obtaining a current indication of strength of signals as received by a receiver in a communication device through a first antenna over a wide channel in a radio frequency band;

obtaining adjacent channel rejection ‘ACR’ information applicable to a modulation technique and data rate currently being used for the receiver, the ‘ACR’ information characterizing tolerance of the receiver when operated in the wide channel to adjacent channel interference ‘ACI’ caused by transmissions by a transmitter in the communication device through a second antenna over a narrow channel in the radio frequency band that is not in the wide channel; and

marking the narrow channel in a channel map as unavailable if the ‘ACR’ information is less than a ratio of a current transmit power level of the transmitter to the current indication of strength of signals.

12. The method as claimed in claim 11 , wherein the radio frequency band is in the unlicensed industrial, scientific and medical ‘ISM’ 2.4 GHz band.

13. The method as claimed in claim 12 , wherein the receiver is a wireless local area network ‘WLAN’ receiver and a width of the wide channels equals 23 MHz.

14. The method as claimed in claim 12 , wherein the transmitter is a wireless personal area network ‘WPAN’ transmitter and a width of the narrow channels equals 1 MHz.