US20040157632A1 - Robust and efficient reacquisition after call release - Google Patents
Robust and efficient reacquisition after call release Download PDFInfo
- Publication number
- US20040157632A1 US20040157632A1 US10/774,106 US77410604A US2004157632A1 US 20040157632 A1 US20040157632 A1 US 20040157632A1 US 77410604 A US77410604 A US 77410604A US 2004157632 A1 US2004157632 A1 US 2004157632A1
- Authority
- US
- United States
- Prior art keywords
- mobile station
- reacquisition
- metric
- threshold
- signal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W48/00—Access restriction; Network selection; Access point selection
- H04W48/20—Selecting an access point
Definitions
- This invention relates to wireless communication systems, and more particularly to enhance reacquisition of the network within wireless communication systems.
- CDMA code division multiple access
- TIA/EIA TIA/EIA
- IS-95 Mobile station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular System
- CDMA is a technique for spread-spectrum multiple-access digital communications that creates channels through the use of unique code sequences.
- signals can be and are received in the presence of high levels of interference. The practical limit of signal reception depends on the channel conditions, but CDMA reception in the system described in the aforementioned IS-95 Standard can take place in the presence of interference that is 18 dB larger than the signal for a static channel.
- the system operates with a lower level of interference and dynamic channel conditions.
- mobile stations acquire the pilot signal of a base station.
- the pilot signal has identifying spreading code used by the mobile station.
- the mobile stations use the pilot signal to synchronize themselves with the base station so the mobile stations can recognize any of the other channels necessary.
- the mobile station may communicate with the base station over the appropriate channels of the wireless communication system.
- the mobile station After completing a call, or upon call release, the mobile station currently resynchronizes with the base station using the sync channel. Under strong signal conditions, this poses no problems. However, when the signal conditions deteriorate, the mobile station may be unable to resynchronize with the pilot base station. What is needed is a system that allows resynchronization under strong signal conditions but allows for reacquisition when signal conditions deteriorate.
- the present invention creates a more robust reacquisition process for the mobile station.
- the mobile station performs an evaluation of the signal conditions from the base station.
- the mobile station may perform this evaluation at the end of a call, upon release, or immediately after release. If the signal is strong, the mobile station will jump directly back to the synchronization channel. However, if the signal has deteriorated, the mobile station may determine it is more appropriate to reacquire the pilot signal of a base station.
- the mobile station may also use the signal characteristics to determine whether to perform a full acquisition, a quick acquisition, or a wide acquisition.
- the mobile station may also use a history to assist in the reacquisition process.
- One aspect of the invention is a method of reacquisition in a wireless communication system.
- the method comprises obtaining a metric indicating of signal conditions and comparing the metric to a first predetermined threshold. If the metric meets or exceeds the first predetermined threshold, the method attempts connection with the synchronization channel. If the metric does not meet the first predetermined threshold, the method performs reacquisition. The method may also compare the metric to a second predetermined threshold and attempt narrow reacquisition if the metric meets or exceed the second predetermined threshold.
- Another aspect of the invention is a method of enhancing reacquisition in a wireless communication system.
- the method comprises determining signal strength and connecting to the synchronization channel if the signal strength meets or exceeds a first threshold.
- the method then performs narrow reacquisition if the signal strength is between the first threshold and a second threshold. If the signal strength is at or below the second threshold, the method performs full reacquisition.
- the method may further creating a history log of reacquisition performance and determine the first threshold and the second threshold using historical data in the history log.
- Another aspect of the invention is a mobile station for use in a wireless communication system.
- the mobile station comprises a signal quality indicator which determines signal quality.
- a reacquisition logic circuit then determines the appropriate reacquisition procedure based on the signal quality.
- FIG. 1 illustrates the components of an exemplary wireless communication system used by one embodiment of the present invention.
- FIG. 2 is a block diagram showing features of a mobile station according to one embodiment of the invention.
- FIG. 3 is a flowchart illustrating the reacquisition process according to one embodiment of the present invention.
- FIG. 1 illustrates components of an exemplary wireless communication system.
- a mobile switching center 102 communicates with base stations 104 a - 104 k (only one connection shown).
- the base stations 104 a - 104 k (generally 104 ) broadcasts data to and receives data from mobile stations 106 within cells 108 a - 108 k (generally 108 ).
- the cell 108 is a geographic region, roughly hexagonal, having a radius of up to 35 kilometers or possibly more.
- a mobile station 106 is capable of receiving data from and transmitting data to a base station 104 .
- the mobile station 106 receives and transmits data according to the Code Division Multiple Access (CDMA) standard.
- CDMA is a communication standard permitting mobile users of wireless communication devices to exchange data over a telephone system wherein radio signals carry data to and from the wireless devices.
- additional cells 108 a, 108 c, 108 d, and 108 e adjacent to the cell 108 b permit mobile stations 106 to cross cell boundaries without interrupting communications. This is so because base stations 104 a, 104 c, 104 d, and 104 e in adjacent cells assume the task of transmitting and receiving data for the mobile stations 106 .
- the mobile switching center 102 coordinates all communication to and from mobile stations 106 in a multi-cell region. Thus, the mobile switching center 102 may communicate with many base stations 104 .
- Mobile stations 106 may move about freely within the cell 108 while communicating either voice or data. Mobile stations 106 not in active communication with other telephone system users may, nevertheless, scan base station 104 transmissions in the cell 108 to detect any telephone calls or paging messages directed to the mobile station 106 .
- a mobile station 106 is a cellular telephone used by a pedestrian who, expecting a telephone call, powers on the cellular telephone while walking in the cell 108 .
- the cellular telephone scans certain frequencies (frequencies known to be used by CDMA) to synchronize communication with the base station 104 .
- the cellular telephone then registers with the mobile switching center 102 to make itself known as an active user within the CDMA network.
- the cellular telephone When detecting a call, the cellular telephone scans data frames broadcast by the base station 104 to detect any telephone calls or paging messages directed to the cellular telephone. In this call detection mode, the cellular telephone receives, stores and examines paging message data, and determines whether the data contains a mobile station identifier matching an identifier of the cellular telephone. If a match is detected, the cellular telephone establishes a call with the mobile switching center 102 via the base station 104 . If no match is detected, the cellular telephone enters an idle state for a predetermined-period of time, then exits the idle state to receive another transmission of paging message data.
- FIG. 2 shows a block diagram of the mobile station 106 and the processing that occurs in that mobile station 106 .
- the processor 200 is driven by a program stored in a memory 205 . Parameters for the mobile station 106 may also be stored in another part of memory shown here as 210 .
- the memory 210 stores various conditions including information obtained from searches to base stations.
- the processor 200 executes a process 300 shown in FIG. 3.
- the process 300 begins at a START state 305 . Proceeding to state 310 , the mobile station 106 enters the acquisition mode to acquire the pilot signal.
- the mobile station 106 may acquire the pilot signal using a full acquisition or a narrow acquisition.
- a full acquisition has the mobile station 106 synchronize with the base station 104 using the pilot signal without any known variables.
- a narrow acquisition may use known variables of the pilot signal such as offset and timing information.
- the mobile station 106 uses the full acquisition. If the mobile station 106 is reacquiring the pilot signal, the narrow acquisition may be used.
- the mobile station 106 performs acquisition using the search element.
- the search element may be configured using a number of parameters. These parameters allow the searcher to restrict the range of several factors, including the pseudo-noise (PN) space that it searches, how much tolerance there is for fading, and how much tolerance there is for frequency error.
- PN pseudo-noise
- the terms “wide” and “narrow” refer to the ranges of these parameters, and in general refers to the PN space. A narrow acquisition might focus on only PN space around the last known pilot whereas a wide acquisition might search all of PN space for all pilots. Similarly, a narrow acquisition could describe a situation where the acquisition does not tolerate much frequency error or other factor.
- the mobile station 106 synchronizes with the base station 104 using the information in the pilot signal.
- the mobile station 106 uses the received pilot signal to synchronize its spreading sequences and phase align its local oscillator (LO). After synchronization, the mobile station 106 can freely communicate with the base station 104 .
- LO local oscillator
- the mobile station 106 enters a page mode.
- the mobile station 106 monitors the base station 104 awaiting communications.
- the base station 104 may address a mobile station 106 in the page mode to, among other things, inform the mobile station 106 of incoming calls. While in the page mode, the mobile station 106 may also enter an idle mode to conserve power.
- the mobile station 106 activates a call with the base station 104 .
- the call activation may be the result of an incoming call and a page by the base station 104 , or an outgoing call initiated by the mobile station 106 .
- the mobile station 106 remains in state 325 during the call process.
- the mobile station 106 proceeds to state 330 to determine the signal strength from the base station 104 .
- the mobile station 106 may determine the signal strength at the end of the call, upon release, or shortly after call release. When the mobile station 106 determines the signal strength may be predetermined and may vary among mobile stations 106 .
- the mobile station 106 uses a variety of indicators to determine signal power. A known standard measurement of forward link system coverage has been to monitor the signal strength of the pilot signal as a function of the total interference density in the CDMA carrier band, popularly known as Ec/Io.
- Other indicators include is a bit error rate, a symbol error rate, a frame error rate, a receiver quality indicator (RX Quality), a receive signal strength indicator (RSSI), also known as RX Level, determining the period of time of a finger lock is maintained, or having the finger correlation of a null/preamble signal above a certain threshold.
- the mobile station 106 uses these indicators to determine the signal quality.
- the bit error rate is the number of erroneous bits in a data transmission.
- the RX Quality is a value assigned by the network indicating the quality of the received signal based upon the bit error rate.
- the RX Quality figure provides a mobile station 106 with an expected measurement accuracy. The mobile station 106 uses the RX Quality to determine the overall potential for error.
- RSSI provides a known value based upon the measured strength of the signal at the mobile station 106 . A stronger signal at the mobile station 106 indicates less likelihood for error.
- Table 2 provides sample values for RSSI based upon the signal strength at the mobile station 106 . Each specific value for RSSI correlates to the strength of the signal (in measured decibels (dBm)) at the mobile station 106 receiver. TABLE 2 RSSI Level at Receiver (dBm) 0 Less than ⁇ 110 1 ⁇ 110 to ⁇ 109 2 ⁇ 109 to ⁇ 108 . . . . . 62 ⁇ 49 to ⁇ 48 63 above ⁇ 48
- the mobile station 106 After determining the signal strength, the mobile station 106 proceeds to state 335 .
- the mobile station determines a confidence level in the signal. This may be accomplished by having a predefined threshold for a quality metric programmed into the mobile station 106 . If the metric meets or exceeds this threshold, then the signal quality is assumed to be good and the mobile station 106 is confident in the signal. However, if the metric is below the threshold, the signal quality is presumed to be weak and the mobile station 106 indicates a lack of confidence in the signal.
- the process 300 proceeds along the YES branch to state 315 where the mobile station resynchronizes with the base station 104 .
- the mobile station 106 then reenters the paging mode to stay in communication with the wireless system.
- the process 300 proceeds along the NO branch to state 340 .
- the signal quality metric is compared against a second threshold level to determine if a lower level of confidence can be assumed.
- the second threshold level is lower than the threshold level used to determine signal confidence in state 335 . If the signal quality exceeds the second threshold, the mobile station 106 proceeds along the YES branch to state 350 .
- the mobile station 106 is set up to perform a narrow acquisition. In a narrow acquisition, the signal quality is high enough to use some known information such as offset and timing information to simplify the acquisition process.
- state 345 the mobile station 106 has a lack of confidence in the prior signal and is therefore set for a full acquisition.
- the full acquisition procedure has the mobile station 106 completely reacquire a base station 104 without using any previously known information.
- the process 300 proceeds to state 310 where the acquisition process is performed.
- the mobile station 104 remains in the process 300 as long as the mobile station is active in the wireless communication system.
- the mobile station 106 may also compile a history log recording the results of the resynchronization or reacquisition attempts.
- the history log may indicate whether the attempts to resynchronize succeeded. Based on this historical data, the mobile station 106 may adjust the values of the threshold values to enhance the success rate of reconnecting with the base station 104 .
Landscapes
- Engineering & Computer Science (AREA)
- Computer Security & Cryptography (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Mobile Radio Communication Systems (AREA)
Abstract
A mobile station provides for a more robust reacquisition process with the base station. The mobile station performs an evaluation of the signal conditions from the base station. The mobile station may perform this evaluation at the end of a call, upon release, or immediately after release. If the signal is strong, the mobile station will jump directly back to the synchronization channel. However, if the signal has deteriorated, the mobile station may determine it is more appropriate to reacquire the pilot signal of a base station. The mobile station may also use the signal characteristics to determine whether to perform a full acquisition, a quick acquisition, or a wide acquisition. The mobile station may also use a history to assist in the reacquisition process.
Description
- This application claims benefit of U.S. Provisional application No. 60/214,111, filed Jul. 26, 2000.
- This invention relates to wireless communication systems, and more particularly to enhance reacquisition of the network within wireless communication systems.
- Cellular telephones may operate under a variety of standards including the code division multiple access (CDMA) cellular telephone communication system as described in TIA/EIA, IS-95, Mobile station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular System, published July 1993. CDMA is a technique for spread-spectrum multiple-access digital communications that creates channels through the use of unique code sequences. In CDMA systems, signals can be and are received in the presence of high levels of interference. The practical limit of signal reception depends on the channel conditions, but CDMA reception in the system described in the aforementioned IS-95 Standard can take place in the presence of interference that is 18 dB larger than the signal for a static channel. Typically, the system operates with a lower level of interference and dynamic channel conditions.
- In current CDMA systems, mobile stations acquire the pilot signal of a base station. The pilot signal has identifying spreading code used by the mobile station. The mobile stations use the pilot signal to synchronize themselves with the base station so the mobile stations can recognize any of the other channels necessary. Once a mobile station acquires the pilot signal of a base station, the mobile station may communicate with the base station over the appropriate channels of the wireless communication system.
- After completing a call, or upon call release, the mobile station currently resynchronizes with the base station using the sync channel. Under strong signal conditions, this poses no problems. However, when the signal conditions deteriorate, the mobile station may be unable to resynchronize with the pilot base station. What is needed is a system that allows resynchronization under strong signal conditions but allows for reacquisition when signal conditions deteriorate.
- The present invention creates a more robust reacquisition process for the mobile station. The mobile station performs an evaluation of the signal conditions from the base station. The mobile station may perform this evaluation at the end of a call, upon release, or immediately after release. If the signal is strong, the mobile station will jump directly back to the synchronization channel. However, if the signal has deteriorated, the mobile station may determine it is more appropriate to reacquire the pilot signal of a base station. The mobile station may also use the signal characteristics to determine whether to perform a full acquisition, a quick acquisition, or a wide acquisition. The mobile station may also use a history to assist in the reacquisition process.
- One aspect of the invention is a method of reacquisition in a wireless communication system. The method comprises obtaining a metric indicating of signal conditions and comparing the metric to a first predetermined threshold. If the metric meets or exceeds the first predetermined threshold, the method attempts connection with the synchronization channel. If the metric does not meet the first predetermined threshold, the method performs reacquisition. The method may also compare the metric to a second predetermined threshold and attempt narrow reacquisition if the metric meets or exceed the second predetermined threshold.
- Another aspect of the invention is a method of enhancing reacquisition in a wireless communication system. The method comprises determining signal strength and connecting to the synchronization channel if the signal strength meets or exceeds a first threshold. The method then performs narrow reacquisition if the signal strength is between the first threshold and a second threshold. If the signal strength is at or below the second threshold, the method performs full reacquisition. The method may further creating a history log of reacquisition performance and determine the first threshold and the second threshold using historical data in the history log.
- Another aspect of the invention is a mobile station for use in a wireless communication system. The mobile station comprises a signal quality indicator which determines signal quality. A reacquisition logic circuit then determines the appropriate reacquisition procedure based on the signal quality.
- These and other features and advantages of the invention will become more apparent upon reading the following detailed description and upon reference to the accompanying drawings.
- FIG. 1 illustrates the components of an exemplary wireless communication system used by one embodiment of the present invention.
- FIG. 2 is a block diagram showing features of a mobile station according to one embodiment of the invention.
- FIG. 3 is a flowchart illustrating the reacquisition process according to one embodiment of the present invention.
- FIG. 1 illustrates components of an exemplary wireless communication system. A
mobile switching center 102 communicates with base stations 104 a-104 k (only one connection shown). The base stations 104 a-104 k (generally 104) broadcasts data to and receives data frommobile stations 106 within cells 108 a-108 k (generally 108). The cell 108 is a geographic region, roughly hexagonal, having a radius of up to 35 kilometers or possibly more. - A
mobile station 106 is capable of receiving data from and transmitting data to a base station 104. In one embodiment, themobile station 106 receives and transmits data according to the Code Division Multiple Access (CDMA) standard. CDMA is a communication standard permitting mobile users of wireless communication devices to exchange data over a telephone system wherein radio signals carry data to and from the wireless devices. - Under the CDMA standard,
additional cells cell 108 b permitmobile stations 106 to cross cell boundaries without interrupting communications. This is so becausebase stations mobile stations 106. Themobile switching center 102 coordinates all communication to and frommobile stations 106 in a multi-cell region. Thus, themobile switching center 102 may communicate with many base stations 104. -
Mobile stations 106 may move about freely within the cell 108 while communicating either voice or data.Mobile stations 106 not in active communication with other telephone system users may, nevertheless, scan base station 104 transmissions in the cell 108 to detect any telephone calls or paging messages directed to themobile station 106. - One example of such a
mobile station 106 is a cellular telephone used by a pedestrian who, expecting a telephone call, powers on the cellular telephone while walking in the cell 108. The cellular telephone scans certain frequencies (frequencies known to be used by CDMA) to synchronize communication with the base station 104. The cellular telephone then registers with themobile switching center 102 to make itself known as an active user within the CDMA network. - When detecting a call, the cellular telephone scans data frames broadcast by the base station104 to detect any telephone calls or paging messages directed to the cellular telephone. In this call detection mode, the cellular telephone receives, stores and examines paging message data, and determines whether the data contains a mobile station identifier matching an identifier of the cellular telephone. If a match is detected, the cellular telephone establishes a call with the
mobile switching center 102 via the base station 104. If no match is detected, the cellular telephone enters an idle state for a predetermined-period of time, then exits the idle state to receive another transmission of paging message data. - FIG. 2 shows a block diagram of the
mobile station 106 and the processing that occurs in thatmobile station 106. Theprocessor 200 is driven by a program stored in amemory 205. Parameters for themobile station 106 may also be stored in another part of memory shown here as 210. Thememory 210 stores various conditions including information obtained from searches to base stations. - The
processor 200 executes aprocess 300 shown in FIG. 3. Theprocess 300 begins at aSTART state 305. Proceeding tostate 310, themobile station 106 enters the acquisition mode to acquire the pilot signal. Themobile station 106 may acquire the pilot signal using a full acquisition or a narrow acquisition. A full acquisition has themobile station 106 synchronize with the base station 104 using the pilot signal without any known variables. A narrow acquisition may use known variables of the pilot signal such as offset and timing information. Of course, when first synchronizing with a pilot signal, themobile station 106 uses the full acquisition. If themobile station 106 is reacquiring the pilot signal, the narrow acquisition may be used. - The
mobile station 106 performs acquisition using the search element. The search element may be configured using a number of parameters. These parameters allow the searcher to restrict the range of several factors, including the pseudo-noise (PN) space that it searches, how much tolerance there is for fading, and how much tolerance there is for frequency error. The terms “wide” and “narrow” refer to the ranges of these parameters, and in general refers to the PN space. A narrow acquisition might focus on only PN space around the last known pilot whereas a wide acquisition might search all of PN space for all pilots. Similarly, a narrow acquisition could describe a situation where the acquisition does not tolerate much frequency error or other factor. - Proceeding to
state 315, themobile station 106 synchronizes with the base station 104 using the information in the pilot signal. Themobile station 106 uses the received pilot signal to synchronize its spreading sequences and phase align its local oscillator (LO). After synchronization, themobile station 106 can freely communicate with the base station 104. - Proceeding to
state 320, themobile station 106 enters a page mode. In the page mode, themobile station 106 monitors the base station 104 awaiting communications. The base station 104 may address amobile station 106 in the page mode to, among other things, inform themobile station 106 of incoming calls. While in the page mode, themobile station 106 may also enter an idle mode to conserve power. - Proceeding to
state 325, themobile station 106 activates a call with the base station 104. The call activation may be the result of an incoming call and a page by the base station 104, or an outgoing call initiated by themobile station 106. Themobile station 106 remains instate 325 during the call process. - At the end of the call, the
mobile station 106 proceeds tostate 330 to determine the signal strength from the base station 104. Themobile station 106 may determine the signal strength at the end of the call, upon release, or shortly after call release. When themobile station 106 determines the signal strength may be predetermined and may vary amongmobile stations 106. Themobile station 106 uses a variety of indicators to determine signal power. A known standard measurement of forward link system coverage has been to monitor the signal strength of the pilot signal as a function of the total interference density in the CDMA carrier band, popularly known as Ec/Io. Other indicators include is a bit error rate, a symbol error rate, a frame error rate, a receiver quality indicator (RX Quality), a receive signal strength indicator (RSSI), also known as RX Level, determining the period of time of a finger lock is maintained, or having the finger correlation of a null/preamble signal above a certain threshold. Themobile station 106 uses these indicators to determine the signal quality. - In particular, the bit error rate is the number of erroneous bits in a data transmission. The RX Quality is a value assigned by the network indicating the quality of the received signal based upon the bit error rate. The RX Quality figure provides a
mobile station 106 with an expected measurement accuracy. Themobile station 106 uses the RX Quality to determine the overall potential for error. - Another measurement that may be used by the
mobile station 106 is RSSI. RSSI provides a known value based upon the measured strength of the signal at themobile station 106. A stronger signal at themobile station 106 indicates less likelihood for error. Table 2 provides sample values for RSSI based upon the signal strength at themobile station 106. Each specific value for RSSI correlates to the strength of the signal (in measured decibels (dBm)) at themobile station 106 receiver.TABLE 2 RSSI Level at Receiver (dBm) 0 Less than −110 1 −110 to −109 2 −109 to −108 . . . . . . 62 −49 to −48 63 above −48 - After determining the signal strength, the
mobile station 106 proceeds tostate 335. Instate 335, the mobile station determines a confidence level in the signal. This may be accomplished by having a predefined threshold for a quality metric programmed into themobile station 106. If the metric meets or exceeds this threshold, then the signal quality is assumed to be good and themobile station 106 is confident in the signal. However, if the metric is below the threshold, the signal quality is presumed to be weak and themobile station 106 indicates a lack of confidence in the signal. - If the signal quality is good and the mobile station is confident in the signal, the
process 300 proceeds along the YES branch tostate 315 where the mobile station resynchronizes with the base station 104. Themobile station 106 then reenters the paging mode to stay in communication with the wireless system. - Returning to
state 335, if the signal quality metric is below the threshold indicating a lack of confidence in the signal, theprocess 300 proceeds along the NO branch tostate 340. Instate 340, the signal quality metric is compared against a second threshold level to determine if a lower level of confidence can be assumed. The second threshold level is lower than the threshold level used to determine signal confidence instate 335. If the signal quality exceeds the second threshold, themobile station 106 proceeds along the YES branch tostate 350. Instate 350, themobile station 106 is set up to perform a narrow acquisition. In a narrow acquisition, the signal quality is high enough to use some known information such as offset and timing information to simplify the acquisition process. - Returning to
state 340, if the signal quality metric falls below the second threshold, theprocess 300 proceeds along the NO branch tostate 345. Instate 345, themobile station 106 has a lack of confidence in the prior signal and is therefore set for a full acquisition. The full acquisition procedure has themobile station 106 completely reacquire a base station 104 without using any previously known information. After themobile station 106 is set for either full acquisition instate 345 or narrow acquisition instate 350, theprocess 300 proceeds tostate 310 where the acquisition process is performed. The mobile station 104 remains in theprocess 300 as long as the mobile station is active in the wireless communication system. - The
mobile station 106 may also compile a history log recording the results of the resynchronization or reacquisition attempts. The history log may indicate whether the attempts to resynchronize succeeded. Based on this historical data, themobile station 106 may adjust the values of the threshold values to enhance the success rate of reconnecting with the base station 104. - Numerous variations and modifications of the invention will become readily apparent to those skilled in the art. Accordingly, the invention may be embodied in other specific forms without departing from its spirit or essential characteristics.
Claims (22)
1. A method of reacquisition in a wireless communication system comprising:
obtaining a metric indicating of signal conditions;
comparing the metric to a first predetermined threshold;
attempting connection with the synchronization channel if the metric meets or exceeds the first predetermined threshold; and
performing reacquisition if the metric does not meet the first predetermined threshold.
2. The method of claim 1 , further comprising comparing the metric to a second predetermined threshold and attempting narrow reacquisition if the metric meets or exceed the second predetermined threshold.
3. The method of claim 1 , wherein the metric indicates signal quality.
4. The method of claim 1 , wherein the metric is receive signal strength indicator (RSSI).
5. The method of claim 1 , wherein the metric is bit error rate.
6. The method of claim 1 , wherein the metric is Ec/Io.
7. The method of claim 1 , wherein the metric is finger correlation.
8. A method of enhancing reacquisition in a wireless communication system comprising:
determining signal strength;
connecting to the synchronization channel if the signal strength meets or exceeds a first threshold;
performing narrow reacquisition if the signal strength is between the first threshold and a second threshold; and
performing full reacquisition if the signal strength is at or below the second threshold.
9. The method of claim 8 , further comprising creating a history log of reacquisition performance.
10. The method of claim 9 , further comprising determining the first threshold and the second threshold using historical data in the history log.
11. The method of claim 8 , wherein the first threshold and the second threshold are predetermined.
12. The method of claim 8 , wherein the signal strength is determined using a signal quality metric.
13. The method of claim 8 , wherein the signal strength is determined by a mobile station.
14. The method of claim 8 , wherein the signal strength is determined upon call release.
15. The method of claim 8 , wherein the signal strength is determined following call release.
16. A mobile station for use in a wireless communication system comprising:
a signal quality indicator which determines signal quality; and
a reacquisition logic circuit which determines the appropriate reacquisition procedure based on the signal quality.
17. The mobile station of claim 16 , wherein the reacquisition logic circuit connects the mobile station to a synchronization channel if the signal quality exceeds a first threshold.
18. The mobile station of claim 16 , wherein the reacquisition logic circuit directs the mobile station to reacquire a base station if the signal quality falls below a first threshold.
19. The mobile station of claim 18 , wherein the reacquisition logic circuit directs the mobile station to perform a narrow reacquisition if the signal quality exceeds a second threshold.
20. The mobile station of claim 16 , wherein the signal quality indicator determines the signal quality using a metric.
21. The mobile station of claim 20 , wherein the metric is RSSI.
22. The mobile station of claim 20 , wherein the metric is finger correlation.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/774,106 US20040157632A1 (en) | 2000-06-26 | 2004-02-06 | Robust and efficient reacquisition after call release |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US21411100P | 2000-06-26 | 2000-06-26 | |
US09/640,481 US6718171B1 (en) | 2000-06-26 | 2000-08-16 | Robust and efficient reacquisition after call release |
US10/774,106 US20040157632A1 (en) | 2000-06-26 | 2004-02-06 | Robust and efficient reacquisition after call release |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/640,481 Division US6718171B1 (en) | 2000-06-26 | 2000-08-16 | Robust and efficient reacquisition after call release |
Publications (1)
Publication Number | Publication Date |
---|---|
US20040157632A1 true US20040157632A1 (en) | 2004-08-12 |
Family
ID=26908689
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/640,481 Expired - Fee Related US6718171B1 (en) | 2000-06-26 | 2000-08-16 | Robust and efficient reacquisition after call release |
US10/774,106 Abandoned US20040157632A1 (en) | 2000-06-26 | 2004-02-06 | Robust and efficient reacquisition after call release |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/640,481 Expired - Fee Related US6718171B1 (en) | 2000-06-26 | 2000-08-16 | Robust and efficient reacquisition after call release |
Country Status (2)
Country | Link |
---|---|
US (2) | US6718171B1 (en) |
JP (1) | JP3666416B2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2019218326A1 (en) * | 2018-05-17 | 2019-11-21 | 北京小米移动软件有限公司 | Measurement report reporting method and device, base station determination method and device, and unmanned aerial vehicle |
Families Citing this family (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6718171B1 (en) * | 2000-06-26 | 2004-04-06 | Denso Corporation | Robust and efficient reacquisition after call release |
KR100469735B1 (en) * | 2000-07-18 | 2005-02-02 | 삼성전자주식회사 | Call admission method in cdma mobile communication system |
US7961616B2 (en) * | 2001-06-07 | 2011-06-14 | Qualcomm Incorporated | Method and apparatus for congestion control in a wireless communication system |
US7092717B2 (en) * | 2002-12-20 | 2006-08-15 | Qualcomm Incorporated | Method and system for a dynamic adjustment of a data request channel in a communication system |
US7760765B2 (en) * | 2003-05-31 | 2010-07-20 | Qualcomm, Incorporated | System and method for the reacquisition of a gated pilot |
KR100703269B1 (en) * | 2005-05-03 | 2007-04-03 | 삼성전자주식회사 | Cell reselection method of a mobile terminal in consideration of service quality |
GB2427790B (en) * | 2005-06-29 | 2008-02-06 | Motorola Inc | Apparatus and method for determining call quality in a communication system |
US8798661B2 (en) * | 2005-12-23 | 2014-08-05 | Qualcomm Incorporated | Method and apparatus for determining output transmit power for an access channel in a wireless communication network |
JP4799213B2 (en) * | 2006-02-28 | 2011-10-26 | 株式会社エヌ・ティ・ティ・ドコモ | Wireless communication terminal and wireless communication method |
JP5222653B2 (en) * | 2008-07-30 | 2013-06-26 | 京セラ株式会社 | Wireless terminal device |
DE102008054658A1 (en) * | 2008-12-15 | 2010-06-17 | Biotronik Crm Patent Ag | Implantable medical device with mobile modem |
EP2302970A1 (en) * | 2009-09-28 | 2011-03-30 | ST-Ericsson (France) SAS | Devices and methods for evaluating for a user equipment the suitability of a cell in a network |
JP6852740B2 (en) | 2017-02-03 | 2021-03-31 | 日本電気株式会社 | Communication processing method, communication terminal and its control program |
Citations (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5910944A (en) * | 1997-02-28 | 1999-06-08 | Motorola, Inc. | Radio telephone and method for operating a radiotelephone in slotted paging mode |
US5966402A (en) * | 1995-11-22 | 1999-10-12 | Sony Corporation | Method and apparatus for detecting pilot signals and subscriber |
US6021123A (en) * | 1995-12-27 | 2000-02-01 | Kabushiki Kaisha Toshiba | Cellular radio system using CDMA scheme |
US6119010A (en) * | 1998-10-13 | 2000-09-12 | Motorola, Inc. | Method and apparatus for adjusting channel powers in a wireless communication system based on a predicted mobile location |
US6263010B1 (en) * | 1997-08-04 | 2001-07-17 | Kabushiki Kaisha Toshiba | Spread spectrum communication apparatus |
US20010021179A1 (en) * | 1999-02-26 | 2001-09-13 | Tiedemann Edward G. | Method and system for handoff between an asynchronous CDMA base station and a synchronous CDMA base station |
US6393295B1 (en) * | 1997-05-30 | 2002-05-21 | Qualcomm Incorporated | Dual event slotted paging |
US6411819B1 (en) * | 1998-11-19 | 2002-06-25 | Scoreboard, Inc. | Method of modeling a neighbor list for a mobile unit in a CDMA cellular telephone system |
US6421540B1 (en) * | 1997-05-30 | 2002-07-16 | Qualcomm Incorporated | Method and apparatus for maximizing standby time using a quick paging channel |
US6473607B1 (en) * | 1998-06-01 | 2002-10-29 | Broadcom Corporation | Communication device with a self-calibrating sleep timer |
US6501958B1 (en) * | 1998-07-29 | 2002-12-31 | Samsung Electronics Co., Ltd. | Method for controlling forward power control utilizing an erasure indicator bit in a CDMA system |
US20030112857A1 (en) * | 2001-12-14 | 2003-06-19 | Cleveland Joseph Robert | Apparatus and method for detecting pilot channel signals with low signal-to-noise |
US6625467B2 (en) * | 2000-07-13 | 2003-09-23 | Qualcomm, Incorporated | Method and apparatus for performing idle mode reacquisition and handoff in an asynchronous communication system |
US6718171B1 (en) * | 2000-06-26 | 2004-04-06 | Denso Corporation | Robust and efficient reacquisition after call release |
US7092717B2 (en) * | 2002-12-20 | 2006-08-15 | Qualcomm Incorporated | Method and system for a dynamic adjustment of a data request channel in a communication system |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100342483B1 (en) * | 2000-09-09 | 2002-06-28 | 윤종용 | Apparatus and method for searching base station in umts |
-
2000
- 2000-08-16 US US09/640,481 patent/US6718171B1/en not_active Expired - Fee Related
-
2001
- 2001-06-22 JP JP2001190310A patent/JP3666416B2/en not_active Expired - Fee Related
-
2004
- 2004-02-06 US US10/774,106 patent/US20040157632A1/en not_active Abandoned
Patent Citations (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5966402A (en) * | 1995-11-22 | 1999-10-12 | Sony Corporation | Method and apparatus for detecting pilot signals and subscriber |
US6021123A (en) * | 1995-12-27 | 2000-02-01 | Kabushiki Kaisha Toshiba | Cellular radio system using CDMA scheme |
US5910944A (en) * | 1997-02-28 | 1999-06-08 | Motorola, Inc. | Radio telephone and method for operating a radiotelephone in slotted paging mode |
US6393295B1 (en) * | 1997-05-30 | 2002-05-21 | Qualcomm Incorporated | Dual event slotted paging |
US6421540B1 (en) * | 1997-05-30 | 2002-07-16 | Qualcomm Incorporated | Method and apparatus for maximizing standby time using a quick paging channel |
US6263010B1 (en) * | 1997-08-04 | 2001-07-17 | Kabushiki Kaisha Toshiba | Spread spectrum communication apparatus |
US6473607B1 (en) * | 1998-06-01 | 2002-10-29 | Broadcom Corporation | Communication device with a self-calibrating sleep timer |
US6501958B1 (en) * | 1998-07-29 | 2002-12-31 | Samsung Electronics Co., Ltd. | Method for controlling forward power control utilizing an erasure indicator bit in a CDMA system |
US6119010A (en) * | 1998-10-13 | 2000-09-12 | Motorola, Inc. | Method and apparatus for adjusting channel powers in a wireless communication system based on a predicted mobile location |
US6411819B1 (en) * | 1998-11-19 | 2002-06-25 | Scoreboard, Inc. | Method of modeling a neighbor list for a mobile unit in a CDMA cellular telephone system |
US20010021179A1 (en) * | 1999-02-26 | 2001-09-13 | Tiedemann Edward G. | Method and system for handoff between an asynchronous CDMA base station and a synchronous CDMA base station |
US6718171B1 (en) * | 2000-06-26 | 2004-04-06 | Denso Corporation | Robust and efficient reacquisition after call release |
US6625467B2 (en) * | 2000-07-13 | 2003-09-23 | Qualcomm, Incorporated | Method and apparatus for performing idle mode reacquisition and handoff in an asynchronous communication system |
US20030112857A1 (en) * | 2001-12-14 | 2003-06-19 | Cleveland Joseph Robert | Apparatus and method for detecting pilot channel signals with low signal-to-noise |
US7092717B2 (en) * | 2002-12-20 | 2006-08-15 | Qualcomm Incorporated | Method and system for a dynamic adjustment of a data request channel in a communication system |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2019218326A1 (en) * | 2018-05-17 | 2019-11-21 | 北京小米移动软件有限公司 | Measurement report reporting method and device, base station determination method and device, and unmanned aerial vehicle |
Also Published As
Publication number | Publication date |
---|---|
JP3666416B2 (en) | 2005-06-29 |
US6718171B1 (en) | 2004-04-06 |
JP2002058075A (en) | 2002-02-22 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7003315B2 (en) | Mobile terminal apparatus and system selecting method | |
JP2802870B2 (en) | Code division multiplex mobile communication apparatus and cell selection method for code division multiplex mobile communication | |
US7286801B2 (en) | Maintaining and searching sets of cells in a wireless communication system | |
US6400952B2 (en) | Method and apparatus for idle handoff in a cellular system | |
US7013140B2 (en) | Mobile terminals and methods for performing fast initial frequency scans and cell searches | |
KR100253104B1 (en) | Method and apparatus for fast pilot channel acquisition using a matched filter in a cdma radiotelephone | |
US6957068B2 (en) | Subscriber station with dynamic multi-mode service acquisition capability | |
US7110376B2 (en) | Method and apparatus for improved cell detection | |
RU2352076C2 (en) | Frame timing and identification of scrambling code in systems of wireless communication and methods for it | |
US5953320A (en) | Method and apparatus for constructing a temporary list of neighboring base stations in a wireless communication device | |
US6647261B1 (en) | Idle handoff method taking into account critical system jobs | |
KR101205631B1 (en) | Method and apparatus for performing a power efficient cell search in a multi-cell wireless communication system | |
US7324479B2 (en) | Cell search method in UMTS | |
US20100046478A1 (en) | Method and system for performing a handoff in a wireless communication system, such as a hard handoff | |
US6718171B1 (en) | Robust and efficient reacquisition after call release | |
US7990901B2 (en) | Cell search scheduling in a wireless cellular communication network | |
US6564062B1 (en) | Pilot search to determine processor loading | |
US7545769B2 (en) | Mobile handoff functionality using asynchronous channel in a communication system | |
US20020137513A1 (en) | Communication terminal apparatus and radio communication method | |
US6678530B1 (en) | Dynamic power control of a channel signal | |
GB2362297A (en) | Location based consideration for cellular telephone handoff | |
KR20050071646A (en) | Dual mode system and dual mode radio terminal |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |