Methods and apparatus for signal monitoring in a wireless communication network
Techniques in a mobile communication device for signal monitoring in a wireless communication network are described. The mobile device operates for communications over a communication channel of the wireless network. During operation, the mobile device periodically obtains measurements of signal quality of the communication channel at a rate R. In addition, the mobile device obtains a measurement of velocity or acceleration of the mobile device. In response to an increase in the measure of velocity or acceleration, the mobile device increases the rate R. Conversely, in response to a decrease in the measurement of velocity or acceleration, the mobile device decreases the rate R. The measurements of the signal quality may be used to determine whether to initiate a handover to a different wireless network. In one illustrative environment, the initial wireless network is a wireless local area network (WLAN), the other wireless network is a wireless wide area network (WWAN), the signal quality is a received signal strength indication (RSSI) of the communication channel, and the monitoring involves obtaining samples of the RSSI.
1. A method in a mobile communication device configured to operate for communications over a communication channel of a wireless local area network (WLAN), the method comprising:
receiving, at the mobile communication device, signals over the communication channel of the WLAN;
sampling, at the mobile communication device at a rate R, a received signal strength indication (RSSI) of the signals received over the communication channel;
obtaining at the mobile communication device a measurement M of velocity or acceleration of the mobile communication device;
repeating the acts of receiving, sampling, and obtaining;
in response to the measure M≦M 1 , setting the rate R=R 1 at the mobile communication device;
in response to the measure M>M 1 , setting the rate R=R 2 at the mobile communication device, where R 2 >R 1 ;
determining at the mobile communication device a signal quality estimate of the communication channel based on a plurality of samples received from the sampling of the RSSI at the rate R; and
providing an indication to permit handover to a wireless wide area network (WWAN) based on the signal quality estimate.
2. The method of claim 1 , wherein the WWAN comprises a cellular telecommunications network.
3. The method, of claim 1 , wherein the act of obtaining the measurement of the velocity or the acceleration is obtained through use of a global positioning system (GPS) receiver or an accelerometer of the mobile communication device.
4. The method of claim 1 , which is performed by computer instructions stored in a non-transitory computer readable medium, the computer instructions being executable on one or more processors of the mobile communication device.
5. The method of claim 1 , wherein the WLAN is operative in accordance with IEEE 802.11 standards.
6. The method of claim 1 , wherein obtaining the measurement M of velocity or acceleration of the mobile communication device comprises obtaining a measurement of velocity of the mobile communication device.
7. A mobile communication device, comprising:
a radio frequency (RF) transceiver configured to receive signals over a communication channel of a wireless local area network (WLAN);
controller circuitry coupled to the RF transceiver;
the controller circuitry being configured to:
sample, at the mobile communication device at a rate R, a received signal strength indication (RSSI) of the signals received over the communication channel;
obtain at the mobile communication device a measurement M of velocity or acceleration of the mobile communication device;
repeat the receiving, the sampling, and the obtaining;
in response to the measure M≦M 1 , set at the mobile communication device the rate R=R 1 ;
in response to the measure M>M 1 , set at the mobile communication device the rate R=R 2 where R 2 >R 1 ;
determine at the mobile communication device a signal quality estimate of the communication channel based on a plurality of samples received from sampling the RSSI at the rate R; and
provide from the mobile communication device an indication to permit handover to a wireless wide area network (WWAN) based on the signal quality estimate.
8. The mobile communication device of claim 7 , wherein the WWAN comprises a cellular telecommunications network.
9. The mobile communication device of claim 7 , wherein the controller circuitry is further configured to obtain the measurement of the velocity or the acceleration through use of a global positioning system (GPS) receiver or an accelerometer of the mobile communication device.
10. The mobile communication device of claim 7 , wherein the WLAN is operative in accordance with IEEE 802.11 standards.
11. The mobile communication device of claim 7 , wherein the controller is further configured to obtain the measurement M of velocity or acceleration of the mobile communication device by obtaining a measurement of velocity of the mobile communication device.