CELL DETECTION

• US 20140177622A1
• Filed: 12/18/2013
• Published: 06/26/2014
• Est. Priority Date: 12/21/2012
• Status: Abandoned Application

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: JUNCKER, Carsten, JOKINEN, Harri Aatos
• Application Number:
  US14/132,037
• Publication Number:
  US 20140177622A1
• Time in Patent Office: Days
• US Class Current: 370/350
• CPC Class Codes: H04L 43/067 using time frame reporting
• CPC Class Codes: H04W 56/00 Synchronisation arrangements

Abstract

Apparatus, a method and a non-transitory computer-readable storage medium including a set of computer-readable instructions stored thereon, which when executed by a processor causes performance of operations, including periodically measure a received signal strength indication of a broadcast control channel received from a current serving cell to detect a presence of a co-channel broadcast control channel interference. In response to determining the presence of the co-channel broadcast control channel interference, a synchronization channel re-read based upon one or more co-channel interference criteria is initiated. The synchronization channel re-read is adapted to determine if one or more neighbouring cells that are broadcasting on the same frequency as the broadcast control channel frequency of the current serving cell would be better than the current serving cell.

Claims

1. A method comprising:

periodically measuring a received signal strength indication of a broadcast control channel received from a current serving cell to detect a presence of a co-channel broadcast control channel interference; and

in response to determining the presence of the co-channel broadcast control channel interference, initiating a synchronization channel re-read based upon one or more co-channel interference criteria;

wherein the synchronization channel re-read is adapted to determine if one or more neighbouring cells that are broadcasting on the same frequency as the broadcast control channel frequency of the current serving cell would be better than the current serving cell.

2. The method according to claim 1, wherein at least one of:

the method further comprising filtering the measured signal strength indication of each broadcast control channel to improve the accuracy of the received signal strength indication;

the presence of co-channel interference is determined by a neighbour cell monitoring function comprising comparing the received signal strength indication of an actual time division multiple access slot of the current serving cell with a power level of one or more frequencies associated with one or more broadcasting neighbouring cells to determine if the current serving cell is located among the top frequencies when ranked according to the measure of the received signal strength indication values;

the co-channel interference criteria comprise a sensitivity versus interference detection function, adapted to classify and switch an I and Q output channel into either an optimized received processing branch associated with sensitivity limited data or an optimized received processing branch associated with interference limited data;

the co-channel interference criteria comprise an interference type detection function adapted to detect and classify interference between adjacent channel interference and co-channel interference;

the co-channel interference criteria comprise a signal-to-co-channel interference ratio function continuously adapting an estimate of the signal-to-co-channel to interference ratio of the serving cell and verifies the estimate against a pre-specified threshold to determine whether the estimated signal-to-co-channel interference ratio exceeds the pre-specified threshold; and

the broadcast control channel is received, over an Evolved Universal Terrestrial Radio Access Network, Universal Terrestrial Radio Access Network, Enhanced Data Rates for Global System for Mobile Communications Evolution network public safety network or a first responder network.

3. The method according to claim 2, wherein the pre-specified threshold is a carrier-to-co-channel interference ratio threshold comprising at least one of:

a threshold value set less than zero decibels wherein the carrier-to-co-channel interference ratio is continuously measured by a user equipment;

a threshold value set to −

3 decibels;

a threshold value a range from −

3 decibels to −

6 decibels; and

a threshold value a set by subtracting a positive numerical valued hysteresis parameter x from a 0 decibels threshold value;

wherein the carrier-to-co-channel interference ratio threshold indicates that a broadcast control channel carrier experienced a single strong co-channel interferer with a power level stronger than the power level of the serving cell or indicates that the broadcast control channel carrier experiences two of more co-channel interferers which add up to a total co-channel interference power that is stronger than the power level of the serving cell.

4. The method according to claim 1, wherein the synchronization channel re-read is adapted to operate in one or more operational modes comprising at least one of:

a standard mode adapted to perform the synchronization channel re-read during a complete frequency control channel search synchronization search repetition period, wherein the synchronization channel re-read is selectively initiated at any uncontrolled point in time during the frequency control channel search or a subsequent synchronization search if a frequency burst is found with a different timing information from the current serving cell;

a repetitive mode adapted to perform the synchronization channel re-read alter the frequency burst of the current serving cell is detected and continuously searches until the frequency burst of the current serving cell is found again or another frequency control channel transmitted from another neighbouring cell is found;

a modified repetitive mode adapted to perform the synchronization channel re-read continuously during the frequency control channel search until the strongest occurrence of a frequency control channel is found; and

a controlled start time mode adapted to perform the synchronization channel re-read a scheduled start time after the detection of the frequency burst of the current serving cell.

5. An apparatus comprising a processing system arranged to cause the apparatus to at least:

periodically measure a received signal strength indication of a broadcast control channel received from a current serving cell to detect a presence of a co-channel broadcast control channel interference; and

in response to determining the presence of the co-channel broadcast control channel interference, initiate a synchronization channel re-read based upon one or more co-channel interference criteria;

wherein the synchronization channel re-read is adapted to determine if one or more neighbouring cells that are broadcasting on the same frequency as the broadcast control channel frequency of the current serving cell would be better than the current serving cell.

6. The apparatus according to claim 5, wherein at least one of:

the apparatus further comprises a signal quality function adapted for filtering the measured signal strength indication of each broadcast control channel to improve the accuracy of the received signal strength indication;

the presence of co-channel interference is determined by a neighbour cell monitoring function, the apparatus being arranged to compare the received signal strength indication of the actual time division multiple access slot of the current serving cell with a power level of one or more frequencies associated with one or more broadcasting neighbouring cells to determine if the current serving cell is located among the top frequencies when ranked according to the measure of the received signal strength indication values;

the co-channel interference criteria comprise a sensitivity versus interference detection function adapted to classify and switch an I and Q output channel into either an optimized received processing branch associated with sensitivity limited data or an optimized received processing branch associated with interference limited data;

the co-channel interference criteria comprise an interference type detection function adapted to detect and classify interference between adjacent channel interference and co-channel interference; and

the co-channel interference criteria comprise a signal-to-co-channel interference ratio function continuously adapting an estimate of the signal-to-co-channel to interference ratio of the serving cell and verifies the estimate against a pre-specified threshold to determine whether the estimated signal-to-co-channel interference ratio exceeds the pre-specified threshold.

7. The apparatus according to claim 6, wherein the pre-specified threshold is a carrier-to-co-channel interference ratio threshold comprising at least one of a threshold value set less than zero decibels wherein the carrier-to-co-channel interference ratio is continuously measured by a user equipment;

a threshold value set to −

3 decibels;

a threshold value a range from −

3 decibels to −

6 decibels; and

a threshold value a set by subtracting a positive numerical valued hysteresis parameter x from a 0 decibels threshold value;

wherein the carrier-to-co-channel interference ratio threshold indicates that a broadcast control channel carrier experienced a single strong co-channel interferer with a power level stronger than the power level of the serving cell or indicates that the broadcast control channel carrier experiences two of more co-channel interferers which add up to a total co-channel interference power that is stronger than the power level of the serving cell.

8. The apparatus according to claim 5, wherein at least one of:

the apparatus is a downlink advance receiver performance phase I, or downlink advance receiver performance phase II, or TIGHTER compliant Global System for Mobile Communications receiver;

the apparatus is coupled to a mobile station or user equipment; and

wherein the mobile station or user equipment is adaptively configured to utilize various enhancement processing techniques to enhance its synchronization performance when operating in interference limited scenarios.

9. The apparatus according to claim 8, wherein at least one of:

the various enhancement processing techniques are based on the techniques required for facilitating a mobile station or user equipment to be either the downlink advance receiver performance phase I, or the downlink advance receiver performance phase II, or the tightened link level performance requirements for single antenna mobile station compliant TIGHTER Global System for Mobile Communications receiver;

the mobile station or user equipment is a smart phone, a cellular phone, a personal digital assistant, a wireless modem, a wireless communication device, a laptop, a netbook, a tablet or any other device cable of communicating with an FirstNet, Evolved Universal Terrestrial Radio Access Network, Universal Terrestrial Radio Access Network, Global System for Mobile Communications, or Enhanced Data Rates for Global System for Mobile Communications Evolution enabled device; and

the broadcast control channel is received over an Evolved Universal Terrestrial Radio Access Network, Universal Terrestrial Radio Access Network, Enhanced Data Rates for Global System for Mobile Communications Evolution network public safety network or a first responder network.

10. The apparatus according to claim 5, wherein the synchronization channel re-read is adapted to operate in one or more operational modes comprising at least one of:

a standard mode adapted to perform the synchronization channel re-read during a complete frequency control channel search synchronization search repetition period, wherein the synchronization channel re-read is selectively initiated at any uncontrolled point in time during the frequency control channel search or a subsequent synchronization search if a frequency burst is found with a different timing information from the current serving cell;

a repetitive mode adapted to perform the synchronization channel re-read after the frequency burst of the current serving cell is detected and continuously searches until the frequency burst of the current serving cell is found again or another frequency control channel transmitted from another neighbouring cell is found;

a modified repetitive mode adapted to perform the synchronization channel re-read continuously during the frequency control channel search until the strongest occurrence of a frequency control channel is found; and

a controlled start time mode adapted to perform the synchronization channel re-read a scheduled start time after the detection of the frequency burst of the current serving cell.

11. A non-transitory computer-readable storage medium comprising a set of computer-readable instructions stored thereon, which, when executed by a processor, causes the processor to:

periodically measure a received signal strength indication of a broadcast control channel received from a current serving cell to detect a presence of a co-channel broadcast control channel interference; and

in response to determining the presence of the co-channel broadcast control channel interference, initiate a synchronization channel re-read based upon one or more co-channel interference criteria;

wherein the synchronization channel re-read is adapted to determine if one or more neighbouring cells that are broadcasting on the same frequency as the broadcast control channel frequency of the current serving cell would be better than the current serving cell.

12. The non-transitory computer-readable storage medium according to claim 11, wherein at least one of:

the method further comprising instructions for filtering the measured signal strength indication of each broadcast control channel to improve the accuracy of the received signal strength indication;

the presence of co-channel interference is determined by a neighbour cell monitoring function comprising comparing the received signal strength indication of an actual time division multiple access slot of the current serving cell with a power level of one or more frequencies associated with one or more broadcasting neighbouring cells to determine if the current serving cell is located among the top frequencies when ranked according to the measure of the received signal strength indication values;

the co-channel interference criteria comprise a sensitivity versus interference detection function adapted to classify and switch an I and Q output channel into either an optimized received processing branch associated with sensitivity limited data or an optimized received processing branch associated with interference limited data;

the co-channel interference criteria is an interference type detection function adapted to detect and classify interference between adjacent channel interference and co-channel interference; and

the co-channel interference criteria comprise a signal-to-co-channel interference ratio function continuously adapting an estimate of the signal-to-co-channel to interference ratio of the serving cell and verifies the estimate against a pre-specified threshold to determine whether the estimated signal-to-co-channel interference ratio exceeds the pre-specified threshold.

13. The non-transitory computer-readable storage medium according to claim 12, wherein the pre-specified threshold is a carrier-to-co-channel interference ratio threshold comprising at least one of:

a threshold value set less than zero decibels wherein the earlier-to-co-channel interference ratio is continuously measured by a user equipment;

a threshold value set to −

3 decibels;

a threshold value a range from −

3 decibels to −

6 decibels; and

a threshold value a set by subtracting a positive numerical valued hysteresis parameter x from a 0 decibels threshold value;

wherein the carrier-to-co-channel interference ratio threshold indicates that a broadcast control channel carrier experienced a single strong co-channel interferer with a power level stronger than the power level of the serving cell or indicates that the broadcast control channel carrier experiences two of more co-channel interferers which add up to a total co-channel interference power that is stronger than the power level of the serving cell.

14. The non-transitory computer-readable storage medium according to claim 11, wherein the broadcast control channel is received over an Evolved Universal Terrestrial Radio Access Network, Universal Terrestrial Radio Access Network, Enhanced Data Rates for Global System for Mobile Communication Evolution network public safety network or a first responder network.

15. The non-transitory computer-readable storage medium according to claim 11, wherein the synchronization channel re-read is adapted to operate in one or more operational modes comprising at least one of:

a standard mode adapted to perform the synchronization channel re-read during a complete frequency control channel search/synchronization search repetition period, wherein the synchronization channel re-read is selectively initiated at any uncontrolled point in time during the frequency control channel search or a subsequent synchronization search if a frequency burst is found with a different timing information from the current serving cell;

a repetitive mode adapted to perform the synchronization channel re-read after the frequency burst of the current serving cell is detected and continuously searches until the frequency burst of the current serving cell is found again or another frequency control channel transmitted from another neighbouring cell is found;

a modified repetitive mode adapted to perform the synchronization channel re-read continuously during the frequency control channel search until the strongest occurrence of a frequency control channel is found; and

a controlled start time mode adapted to perform the synchronization channel re-read a scheduled start time after the detection of the frequency burst of the current serving cell.