Wakeup Synchronization for Frequency Hopping Systems

A method of synchronizing a timing of a wireless communication device with a network node, the wireless communication device configured to operate according to a frequency hopping pattern defined by the network node, the frequency hopping pattern comprising a dwell time representing a time interval between frequency hops, and the wireless communication device configured to receive downlink signals from the network node and to transmit uplink signals to the network node, the method performed by the wireless communication device and comprising:

• determining a maximum timing deviation responsive to a sleep time after the wireless communication device wakes up from a sleep mode, the sleep time representing a duration of the sleep mode;
• computing an estimated time overlap from a difference between the dwell time and the maximum timing deviation;
• selecting a first synchronization procedure when the estimated time overlap exceeds a threshold, wherein the first synchronization procedure assumes a known timing position of the wireless communication device within the frequency hopping pattern;
• selecting a second synchronization procedure when the estimated time overlap is less than or equal to the threshold, wherein the second synchronization procedure assumes an unknown timing position of the wireless communication device within the frequency hopping pattern;
• and
• synchronizing the timing of the wireless communication device using the selected synchronization procedure.

A wireless communication device configured to receive downlink signals from a network node and to transmit uplink signals to the network node, the wireless communication device configured to operate according to a frequency hopping pattern defined by the network node, the frequency hopping pattern comprising a dwell time representing a time interval between frequency hops, the wireless communication device comprising:

• a timing circuit configured to:
• determine a maximum timing deviation responsive to a sleep time after the wireless communication device wakes up from a sleep mode, the sleep time representing a duration of the sleep mode;
• compute an estimated time overlap from a difference between the dwell time and the maximum timing deviation;
• a selection circuit configured to:
• select a first synchronization procedure when the estimated time overlap exceeds a threshold, wherein the first synchronization procedure assumes a known timing position of the wireless communication device within the frequency hopping pattern;
• select a second synchronization procedure when the estimated time overlap is less than or equal to the threshold, wherein the second synchronization procedure assumes an unknown timing position of the wireless communication device within the frequency hopping pattern;
• and
• a synchronization circuit configured to synchronize the timing of the wireless communication device using the selected synchronization procedure.

A non-transitory computer readable recording medium storing a computer program product for synchronizing a timing of a wireless communication device with a network node, the wireless communication device configured to operate according to a frequency hopping pattern defined by the network node, the frequency hopping pattern comprising a dwell time representing a time interval between frequency hops, and the wireless communication device configured to receive downlink signals from the network node and to transmit uplink signals to the network node, the computer program product comprising software instructions which, when run on processing circuitry of the wireless communication device, causes the wireless communication device to:

• determine a maximum timing deviation responsive to a sleep time after the wireless communication device wakes up from a sleep mode, the sleep time representing a duration of the sleep mode;
• compute an estimated time overlap from a difference between the dwell time and the maximum timing deviation;
• select a first synchronization procedure when the estimated time overlap exceeds a threshold, wherein the first synchronization procedure assumes a known timing position of the wireless communication device within the frequency hopping pattern;
• select a second synchronization procedure when the estimated time overlap is less than or equal to the threshold, wherein the second synchronization procedure assumes an unknown timing position of the wireless communication device within the frequency hopping pattern;
• and
• synchronize the timing of the wireless communication device using the selected synchronization procedure.