Bluetooth polling with fewer poll packets
View Patent ↗A Bluetooth master unit polls a slave unit to enable the slave to resynchronize to the master, by sending POLL packets with sufficient frequency to maintain a connection to the slave, and in the intervals between such packets, sending NULL packets with sufficient frequency to maintain synchronization of the slave. By replacing some POLL packets with NULL packets, since the slave does not have to respond to a NULL packet, it can save some power, and there is reduced interference on other piconets. The frequency of the remaining POLL packets is set according to a Link Supervision Timeout (to avoid having this timer expire and thus keep the Bluetooth Link to the slave alive) and according to the time since the master received the last packet from the slave.
1. A master wireless unit arranged to communicate with a slave wireless unit by sending packets, and having a controller configured to arrange to address the slave to enable the slave to resynchronize to the master by transmitting packets in a polling mode in which packets are addressed to the slave individually rather than broadcast and in which the packets are transmitted at intervals sufficient to maintain synchronization to the slave, the packets transmitted in the polling mode including first packets of a type which prompt a response from the slave, the first packets transmitted at a rate to maintain a connection to the slave, and in each interval between successive first packets, the packets transmitted in the polling mode further including several second packets of a type which need no response by the slave, to maintain synchronization of the slave, wherein the first packets and the second packets are transmitted in the polling mode in a repeating sequence.
2. The master unit according to claim 1 , wherein the controller is adapted to set a ratio of the number of first packets sent within a time period of a type which prompt a response from the slave to the number of second packets sent within the same time period which need no response.
3. The master unit according to claim 2 , wherein the controller is adapted to set a different ratio within the time period while keeping the total number of first packets of a type which prompt a response and second packets which need no response the same.
4. The master unit according to claim 1 , wherein the master unit comprises means for providing a frequency hop scheme.
5. The master unit of claim 1 , arranged to use a Bluetooth standard for communicating with the slave unit.
6. The master unit of claim 1 , arranged to send first packets of the type which prompt a response from the slave when the slave unit is in an active mode.
7. The master unit of claim 1 , wherein the second packets of the type which need no response are Bluetooth NULL packets.
8. The master unit of claim 1 , wherein the first packets of the type which prompt a response are Bluetooth POLL packets.
9. The master unit of claim 1 , wherein the rate of sending the first packets of the type which prompt a response, is set in accordance with a Link Supervision Timeout.
10. The master unit of claim 1 , wherein the rate of sending the first packets of the type which prompt a response, is set in accordance with a time since the master received the last packet from the slave.
11. Consumer equipment having the master unit of claim 1 .
12. A computer readable medium encoded with a computer program which, when executed by a controller of a master radio, carries out the steps of:
addressing a slave, by the control of the master radio, to enable the slave to resynchronize to the master by transmitting packets in a polling mode in which packets are addressed to the slave individually rather than broadcast and in which the packets are transmitted at intervals sufficient to maintain synchronization to the slave, the packets transmitted in the polling mode including first packets of a type which prompt a response from the slave, the first packets transmitted at a rate to maintain a connection to the slave, and in each interval between successive first packets, the packets transmitted in the polling mode further including several second packets of a type which need no response by the slave, to maintain synchronization of the slave, wherein the first packets and the second packets are transmitted in the polling mode in a repeating sequence.
13. A method of using a master wireless unit to communicate with a slave wireless unit by sending packets and having the steps of addressing the slave to enable the slave to resynchronize to the master, by transmitting packets in a polling mode in which packets are addressed to the slave individually rather than broadcast and in which the packets are transmitted at intervals sufficient to maintain synchronization to the slave, the packets transmitted in the polling mode including first packets of a type which prompt a response from the slave the first packets transmitted at a rate, to maintain a connection to the slave, and in each interval between successive first packets, the packets transmitted in the polling mode further including several second packets of a type which need no response by the slave, to maintain synchronization of the slave, wherein the first packets and the second packets are transmitted in the polling mode in a repeating sequence.
14. The method of claim 13 , further comprising setting a ratio of first packets of a type which prompt a response from the slave to second packets which need no response.
15. The method according to claim 14 , wherein setting a ratio includes setting a different ratio within a time period while keeping the total number of first packets of a type which prompt a response and second packets which need no response the same.
16. The method of claim 13 , wherein the second packets of the type which need no response are Bluetooth NULL packets.
17. The method of claim 13 , wherein the first packets of the type which prompt a response are Bluetooth POLL packets.
18. The method of claim 13 , wherein the rate of sending the first packets of the type which prompt a response is set in accordance with a Link Supervision Timeout.
19. The method of claim 13 , wherein the rate of sending the first packets of the type which prompt a response is set in accordance with a time since the master received the last packet from the slave.