DETAILED DESCRIPTION

[0037] The present invention uses short layer 2 signalling to facilitate location determination of the MS within a network. The usage of shorter messages (layer 2 message) significantly over-performs the use of longer messages (e.g., layer 3). In accordance with an embodiment of the present invention, a method of three-level location update by MSs in dormant state is provided. The three-level location update in accordance with the present invention may be applied to a cdma2000 system, for example.

[0038] In an example of the present invention, a three-level location update mechanism is defined that is a “sector level” location update, an “area level” location update, and a completion of location update (i.e., a “network level”).

[0039] In the sector level location update, after an MS enters a dormant state, it reports its location whenever it performs an idle handoff. This operation is called a “sector level” location update and operates only for a certain period of time. The purpose of the “sector level” location update is to speed up the packet data state transition from dormant to active.

[0040] In the area level location update, after the “sector level” location update period, the MS reduces the frequency of location update. The MS performs location update once every specified number of idle handoffs. This operation is called “area level” location update and is performed for a certain period of time. The purpose of the “area level” location update is to significantly reduce the location update overhead (compared to the case of “sector level” location update) and still provide information on an MS's ‘rough location’ for the network to estimate the paging area.

[0041] In the completion of location update, after the operation of the “area level” location update, an MS stops updating its location completely. At this level, the existing operation procedure for an MS in a dormant state is performed. Regarding the location update, the network operates at three levels: i.e., a sector level, an area level (page control mechanism), and a network level.

[0042] Whenever the network requires an MS to go to dormant through a “release” message, two timer values are defined, T1 and T2. Here, T1 specifies the time period when operating on the “sector level” location update and T2 specifies the time period when operating on the “area level” location update. The values of T1 and T2 are defined based on the parameters such as the traffic type, the system load, the MS's type and so on. When an MS enters the dormant state, the timer starts counting and when it reaches T1, it stops. Then, the timer restarts counting and when it reaches T2, it stops.

[0043] Due to the “location update” messages being sent over the random channel by the MSs, the “location update” message should be as short as possible in order to increase the throughput and reduce the interference. In this message, only the absolutely necessary information is carried, which is an MS_ID, to uniquely identify the MS.

[0044] This MS_ID is sent over a layer 2 message. The MS_ID is assigned either during call setup or whenever the MS enters dormant state. The MS sends the location update layer 2 message on the reverse link random access channel associated with the sector selected by the MSs. Therefore, when the network receives the layer 2 message, both the MS and the sector are uniquely identified.

[0045] Any radio environment related information (such as pilot strength measurements) will not be attached with each “location update” message and can be sent on the dedicated channel if needed when an MS is brought back to the active state.

[0046] For the sake of reliability of the location update operation, an acknowledgement to the “location update” message is implemented. However, this is an optional operation and the network can decide whether such an acknowledgement is required or not through a control bit along with the “release” message which brings the MS to the dormant state.

[0047] The sector level location update is performed. When the MS goes to a dormant state, the timer is set to count and it continues up to T1. In today's system, when the MS is in the dormant state, it continuously monitors the pilot strength of the surrounding sectors. The MS typically selects a sector with the highest pilot strength to monitor any paging information from the network. When a new sector with the highest pilot strength is detected, the MS performs an idle handoff and puts this new sector into its active set (1 member). In accordance with an embodiment of the present invention, the location update is performed after the occurrence of every idle handoff. The location update procedure is performed until the timer reaches T1. Therefore, before the timer counts T1, the network is able to assign resources to the MS immediately on the reported sector and bring the MS back to its active state when needed. This feature is called fast call setup. When the timer reaches T1, the MS starts the “area level” location update procedure, and the timer restarts counting until T2.

[0048] When an MS starts the “area level” location update procedure, the timer restarts counting and the MS reports its location through the “location update” message. The trigger for sending the “location update” message is a further criterion such as a timer based, distance based, or count of idle handoff based criteria. The frequency of sending the “location update” message in this period should be much lower than that during the “sector level” operation. If the network needs to page an MS, the network can perform the paging in a larger area than one sector but much smaller area than the entire network and the specifics of this page is implementation specific. For example, if the further criterion is time based (such as every 15 minutes where the period of T2 is perhaps 3 hours), the paging should be in sectors consistent with the distance an MS could travel during that 15 minute interval. If the further criterion is distance based, then the network page need only cover the area in which the MS could travel without causing a location update message being sent. If the further criterion is based on counting idle handoffs, a predefined number of idle handoffs can be counted or a predetermined number of idle handoffs indicating a move of the MS into a new sector can be counted. When the timer reaches T2, the MS starts the “network level” location update procedure.

[0049] The network location update is performed. An MS stops sending any location update message and the network has to do the general paging when needed. After an MS stops sending the “location update” message, the existing procedure is resumed.

[0050] The network can configure the MS to bypass the “sector level” and/or the “area level” update. By setting T1 as 0, the “sector level” update is bypassed. By setting T2 as 0, the “area level” update is bypassed.

[0051] In order to support the three-level location update operation, the existing layer 3 message (resource release message (RRM)/resource release mini-message (RRMM) can be modified to include the values of T1 and T2 and the “location update acknowledge required” flag. The value of T1 and/or T2 could be zero, which means that there is no corresponding location update period. The “location update acknowledge required” flag (one bit) can be set or reset to show whether the acknowledgement to the “location update” message is supported.

[0052] In order to support a short message (5 ms layer 2 message), two options are disclosed. 1) Option 1 is to modify the header part in the existing reservation mode of the reverse link enhanced access channel (R-EACH). Such modified header format is shown in Tables hereinafter. Option 2 is to define a new 5 ms frame (9.6 kb/s) for basic mode operation of R-EACH. The layer 2 information carried on this frame is same as Option 1. As the long code mask includes the identification of sector used, R-EACH channel, the relationship between the MS and the selected R-EACH channel of the selected sector is unique.

[0053] A new MS_ID is defined and sent in the “location update” message. This MS_ID length can be, e.g., 24 bit, to uniquely identify an MS in the dormant state that supports location update operation. The MS_ID is sent through the reverse link channels associated with the sector which the MS selected as the member of its active set (the long code mask used for the transmission of the “location update” message) includes the sector ID. Therefore, the one-to-one relationship between the MS and the sector is clearly identified. The MS_ID can be assigned either at the registration of the MS or whenever an MS goes to the dormant state through the existing RRM/RRMM.

[0054] If the network supports the feature of acknowledging the “location update” message, the ACK can be sent on the forward link channel assignment channel (F-CACH) or on the forward link common control channel (F-CCCH).

[0055] If the network wants to bring an MS in the dormant state back to active state before the expiration of T1, the network can send the Enhanced Channel Assignment message (ECAM) on F_CCCH channel and bring the MS back to the active state. If multi-legs operation (multiple members in an active set of MSs in a soft handoff) is required, the network can require the MS to report its radio environment through the pilot strength measurement message (PSMM)/pilot strength measurement mini-message (PSMMM) or the MS can autonomously sends PSMM/PSMMM once it acquires the traffic channel.

[0056] When the network wants to either bring an MS back or has short data to send to an MS when the MS is operating in the “area level” location update period, the network decides the paging range based on the parameters which control the rule of location update operation.

[0057] In another example of the present invention, the overhead caused by the location update is to define a MAC layer message for the purpose of location update is reduced. When the network brings an MS to the dormant state, the network assigns a specific length (e.g., 24-bit) mobile station identifier, LOC_UP_MS_ID, to the MS in a L3 signalling message.

[0058] Whenever an MS in the dormant state reports its location, instead of sending a L3 message with radio environment report, the MS sends its LOC_UP_MS_ID contained in a MAC layer “location update” message over a random channel associated with the sector the MS is monitoring. In this way, the network obtains the information on the MS's location. The additional radio environment report can be sent on the dedicated channel if needed, once a dedicated channel is acquired.

[0059] Since the MAC layer “location update” message contains much fewer information bits than a L3 layer message, the MAC layer message can be sent, for example, in a frame with the length of 5 ms at rate of 9.6 kbps. The shorter message length sent over the random channel reduces the interference and increases the throughput by reducing the possibility of collisions. The network can acknowledge each “location update” message by using the existing MAC layer ACK mechanism.

[0060] FIG. 1 shows a wireless access network that can operate in accordance with an embodiment of the present invention. In FIG. 1 , the network includes a plurality of Base Transceiver Stations (BTSs) (here only two BTSs 111 and 113 are shown for simplicity). Each of the BTSs provides communication links among a plurality of MSs (MSs) (here only three MSs 121 , 123 and 125 are shown for simplicity) and between the MSs. The BTSs are connected to a Base Station Controller (BSC) 141 which is connected to a wireline network such as the Public Switching Telephone Network (PSTN) 131 . The BSC 141 controls communication operations in the system, the operation being in relation to a back haul between the PSTN 131 and the BTSs. The BSC 141 and BTSs 111 and 113 each have central processing units (CPU) and related data store means (not shown) to perform the communication and other functions. Also, each of the MSs 121 - 125 has a CPU and related data store means (not shown) to perform the communication and the other functions. Each of the MSs 121 - 125 provides a timer function to enable the location update operation. The timer's function may be achieved by the CPU of the MS. The timer starts when the MS enters its dormant state. The timer stops when it reaches a specified value T1. Thereafter, the timer restarts and it stops when it reaches another specified value T2.

[0061] The network shown in FIG. 1 operates at three levels: i.e., a sector level, an area level (page control mechanism), and a network level. The network and the MSs communicate with the R_EACH messages and the F_CACH messages. Table I shows the format of the release C R_EACH header (32 bits). 1

[0062] In Table I,

[0063] HASH_ID: Hash Idenfifier.

[0064] The MS shall set this field to HASH_ID _S . HASH_ID is for identification by F_CASH.

[0065] RATE_WORD: Rate and frame size indicator.

[0066] The MS shall set this field according to Table II to indicate the requested transmission rate and frame size of the data to be transmitted on R-CCCH. RATE_WORD indicates one of six configurations.

[0067] MODE_ID: Mode Identifier.

[0068] The MS shall set this field to ‘0’. Other values for this field are reserved.

[0069] HO_REQ_ID: Handoff Request Identifier.

[0070] The MS shall include this field if MODE_ID is set to ‘0’.

[0071] Otherwise, the MS shall omit this field.

[0072] NEIGHBOR_PN: Neighbor Pilot PN Offset.

[0073] The MS shall include this field only if HO_REQ_ID is included and set to ‘1’. If included, the MS shall set this field to the neighbor pilot PN offset.

[0074] RESERVED: Reserved bits.

[0075] The MS shall set this field so that the total number of bits in this message is 32. The MS shall set all the reserved bits to ‘0’.

[0076] Table II shows the RATE_WORD Encoding. 2

[0077] Table III shows the format of a location update message (LUM). 3

[0078] In Table III,

[0079] RESERVED: Reserved bits.

[0080] The MS shall set this field so that the total number of bits in this message is 32. The MS shall set all the reserved bits to ‘0’.

[0081] MS_ID: Mobile station identifier.

[0082] The MS shall set this field to LOC_UP_MS_IDs.

[0083] MSG_TYPE: Message Type.

[0084] The MS shall set this field to ‘10’.

[0085] Table IV shows the format of a reconnect message. 4

[0086] In Table IV,

[0087] RESERVED: Reserved bits.

[0088] The MS shall set this field so that the total number of bits in this message is 32. The MS shall set all the reserved bits to ‘0’.

[0089] MS_ID: Mobile station identifier.

[0090] The MS shall set this field to LOC_UP_MS_IDs.

[0091] MSG_TYPE: Message Type.

[0092] The MS shall set this field to ‘01’.

[0093] Table V shows the format of a reservation request message. 5

[0094] In Table V,

[0095] RESERVED: Reserved bits.

[0096] The MS shall set this field so that the total number of bits in this message is 32. The MS shall set all the reserved bits to ‘0’.

[0097] HASH_ID: Hash Identifier.

[0098] The MS shall set this field to HASH_ID _S . HASH_ID is for identification by F_CASH.

[0099] MODE_ID: Mode Identifier.

[0100] The MS shall set this field to ‘0’. Other values for this field are reserved.

[0101] RATE_WORD: Rate and frame size indicator.

[0102] The MS shall set this field according to Table II to indicate the requested transmission rate and frame size of the data to be transmitted on R-CCCH.

[0103] HO_REQ_ID: Handoff Request Identifier.

[0104] The MS shall include this field if MODE_ID is set to ‘0’.

[0105] Otherwise, the MS shall omit this field.

[0106] NEIGHBOR_PN: Neighbor Pilot PN Offset.

[0107] The MS shall include this field only if HO_REQ_ID is included and set to ‘1’. If included, the MS shall set this field to the neighbor pilot PN offset.

[0108] MSG_TYPE: Message Type.

[0109] The MS shall set this field to ‘00’.

[0110] Table VI shows the format of an Early Acknowledgement Channel Assignment Message (EACAM). 6

[0111] In Table VI,

[0112] MSG_TYPE: Message Type.

[0113] The BTS shall set this field to ‘000’.

[0114] HASH_ID: Hash Identifier.

[0115] The BTS shall set this field to the HASH_ID field of the corresponding Enhanced Access Channel header received from the MS.

[0116] RATE_WORD: Rate and frame duration indicator.

[0117] The BTS shall set this field according to above-mentioned Table II to indicate the transmission rate and frame duration of the R-CCCH that the BTS grants to the MS. The BTS should determine the rate and frame duration based on the RATE_WORD field of the corresponding Enhanced Access Channel header received from the MS.

[0118] RCCCH_ID: Reverse Common Channel Identifier.

[0119] The BTS shall set this field to the R-CCCH index that the BTS grants to the MS.

[0120] CPCCH_ID: Common Power Control Channel Identifier.

[0121] The BTS shall set this field to the index of the Common Power Control Channel.

[0122] HO_FLAG: Handoff Flag.

[0123] The BTS shall set this field to ‘1’ if the HO_REQ_ID field of the corresponding Enhanced Access Channel header received from the MS is equal to ‘1’ and the BTS grants the request for Power Control Subchannel being in soft-handoff. Otherwise, the BTS shall set this field to ‘0’.

[0124] RESERVED: Reserved bits.

[0125] The BTS shall set all the bits in this field to ‘0’.

[0126] Table VII shows the format of a power control channel assignment message (PCCAM). 7

[0127] In Table VII,

[0128] MSG_TYPE: Message Type.

[0129] The BTS shall set this field to ‘001’.

[0130] HASH_ID: Hash Identifier.

[0131] The BTS shall set this field to the HASH_ID field of the corresponding Enhanced Access Channel header received from the MS.

[0132] CPCCH_ID _— 2: Common Power Control Channel Identifier.

[0133] The BTS shall set this field to the Common PC Channel corresponding to the neighbor BTS.

[0134] CPCSCH _— 2: Common Power Control Subchannel Identifier.

[0135] The BTS shall set this field to the Common PC Sub-channel corresponding to the neighbor BTS.

[0136] POWER_COMB_IND: PC bits combine Indicator.

[0137] If the BTS instructs the MS to combine the PC bits received from the neighbor BTS, the BTS shall set this field to ‘1’. Otherwise, the BTS shall set this field to ‘0’.

[0138] RESERVED: Reserved bits.

[0139] The BTS shall set this field to ‘000’.

[0140] Table VIII shows the format of a location update acknowledgment message (LUAM). 8

[0141] In Table VIII,

[0142] MSG_TYPE: Message Type.

[0143] The BTS shall set this field to ‘010’.

[0144] MS_ID: Mobile station identifier.

[0145] The BTS shall set this field to the LOC_UP_MS_ID field of the corresponding Location Update Message received from the MS.

[0146] RESERVED: Reserved bits.

[0147] The BTS shall set this field to ‘00000’.

[0148] Table IX shows the format of a modified message format of a data burst acknowledgement message (DBAM). 9

[0149] In Table IX,

[0150] MSG_TYPE: Message Type.

[0151] The BTS shall set this field to ‘011’.

[0152] MS_ID: Mobile station identifier.

[0153] The BTS shall set this field to the LOC_UP_MS_ID field of the corresponding Location Update Message received from the MS.

[0154] RESERVED: Reserved bits.

[0155] The BTS shall set this field to ‘00000’.

[0156] FIG. 2 shows a method of location update by an MS. The BTS and the MS communicate with the R_EACH messages and the F_CACH messages. Referring to FIGS. 1 and 2 , the location update initiated by an MS will be described.

[0157] The values of T1 and T2 are defined based on the parameters such as the traffic type, the system load, the MS's type and so on. The values of T1 and T2 are determined by the BSC 141 and sent by the BSC 141 (of the sector) to the MSs 121 - 125 .

[0158] The MS initiates the location update. When the MS (e.g., the MS 121 ) enters its dormant state, the timer of the MS starts counting. The MS sends a message consisting of a preamble and header (MSG_Type=00) to the BTS 1 (e.g., the BTS 111 ) through the reverse link. The location update header is shown in Table III (MSG_TYPE of two bits). The BTS 1 sends back a location update acknowledgement message (MSG_Type=010) through the forward link to the MS. The location update acknowledgement message of three bits is shown in Table VIII (MSG_TYPE of three bits). Before sending the location update acknowledgement message to the MS, the BTS 1 notifies the BSC 141 to identify the update of the active set of the MS (Active_set info (MS_ID)). This is repeated in a case where the timer does not reach T1. The location of the dormant MS is updated.

[0159] If the MS 121 moves physically outside the geographic area served by the BTS 111 to another area served by the BTS 2 (e.g., the BTS 113 ), the MS 121 sends a message consisting of a preamble and header (MSG_Type=00) only to the BTS 2 through the reverse link. The BTS 2 sends back a location update acknowledgement message (MSG_Type=010) through the forward link to the MS. Before responding to the MS, the BTS 2 sends the BSC 141 a message identifying the MS (Active_set info (MS_ID)). The location of the dormant MS is updated.

[0160] The “location update” message is short in order to increase the throughput and reduce the interference. In this message, only the absolutely necessary information is carried, which is an MS_ID, to uniquely identify the MS. This MS_ID is sent over a layer 2 message. The MS sends the location update layer 2 message on the reverse link random access channel associated with the sector selected by the MSs. Therefore, when the network receives the layer 2 message, both the MS and the sector are uniquely identified.

[0161] Any radio environment related information (such as pilot strength measurements) will not be attached with each “location update” message and can be sent on a dedicated channel if needed when an MS is brought back to active state.

[0162] In the embodiment, the BTS sends back the acknowledgement message to the MS that initiated the location update. For the sake of reliability of location update operation, an acknowledgement to the “location update” message is implemented. However this is optional operation and the network can decide whether such an acknowledgement is required or not through a control bit along with the “release” message which brings the MS to the dormant state.

[0163] The timer is set to count when the MS goes to dormant state and continues counting up to T1. In today's systems, when the MS is in the dormant state, it continuously monitors the pilot strength of the surrounding sectors. The MS typically selects a sector with the highest pilot strength to monitor any paging information from the network. When a new sector with the highest pilot strength is detected, the MS performs an idle handoff and put this new sector into its active set (1 member).

[0164] In accordance with an embodiment of the present invention, the location update is performed after the occurrence of every idle handoff. The location update procedure is performed as long as the timer does not reach T1. Therefore, before the timer counts T1, the network is able to assign resources to the MS immediately on the reported sector and bring the MS back to its active state when needed. This feature is called fast call setup. When the timer reaches T1, the MS starts the “area level” location update procedure, and the timer starts counting until T2.

[0165] When an MS starts the “area level” location update procedure, the timer starts counting and the MS reports its location through the “location update” message. The trigger for sending the “location update” message is a further criterion such as a timer based, distance based or count of idle handoff based criteria. The frequency of sending the “location update” message in this period should be much lower than that during the “sector level” operation. When the timer reaches T2, the MS starts the “network level” location update procedure. An MS stops sending any location update message and the network has to do the general paging when needed.

[0166] If the network needs to page an MS, it can do the paging in a larger area than one sector but much smaller area than the entire network and the specifics of this page is implementation specific. For example, if the further criterion is time based (such as every 15 minutes where the period of T2 is perhaps 3 hours), the paging should be in sectors consistent with the distance an MS could travel during that 15 minute interval. If the further criterion is distance based, then the network page need only cover the area in which the MS could travel without causing a location update message being sent. If the further criterion is based on counting idle handoffs, a predefined number of idle handoffs can be counted or a predetermined number of idle handoffs indicating a move of the MS into a new sector can be counted.

[0167] The network can bring an MS in the dormant state back to active state before the expiration of T1. FIGS. 3A and 3B show the procedure of the dormant to active state transition initiated by the MS. Referring to FIGS. 1 and 3 A and 3 B, the dormant to active state transition by an MS will be described.

[0168] The MS (e.g., the MS 121 ) sends a message consisting of a preamble and header (MSG_Type=01) to the BTS (e.g., the BTS 111 ) through the reverse link. The reconnect header is shown in Table IV (MSG_TYPE of two bits). The BTS sends back the enhanced channel assignment message (ECAM). The MS returns to its active state and operates on one leg mode (i.e., one member in an active set). Later, the MS sends a pilot report message to the BTS over R_FCH/DCCH. This achieves higher throughput than R_REACH. Where multi-legs operation is required, the BTS sends ECAM (multiple members of active set) message to the MS over F_FCH/PDCH, because the network requires that the MS to report its radio environment through PSMM/PSMMM or the MS can autonomously sends PSMM/PSMMM once it acquires the traffic channel.

[0169] There are two options to send the ECAM via the BTS to the MS. Option 1 is to send the ECAM over F_CCCH as shown in FIG. 3A . Option 2 is to send the ECAM over F_CACH as shown in FIG. 3B . Option 2 is more efficient than option 1, but the length of message in over F_CACH is restricted.

[0170] When the network wants to either bring an MS back or has short data to send to an MS when the MS is operation in the “area level” location update period, the network decides the paging range based on the parameters which control the rule of location update operation.

[0171] The network can bring an MS in the dormant state back to active state initiated by the BTS. FIGS. 4A and 4B show the procedure of the dormant to active state transition initiated by the BTS. Referring to FIGS. 1 and 4 A and 4 B, the dormant to active state transition initiated by the BTS will be described.

[0172] The BTS initiates the location update in response to the MS's location update. The MS (e.g., the MS 121 ) sends a message consisting of a preamble and header (MSG_Type=00) to the BTS (e.g., the BTS 111 ) through the reverse link (R_EACH). The location update header is shown in Table III (MSG_TYPE of two bits). The BTS sends back a location update acknowledgement message (MSG_Type=010) through the forward link (F_CACH) to the MS. The location update acknowledgement message of three bits is shown in Table VIII (MSG_TYPE of three bits). In this case, the network is now aware of the location of the MS and the BTS sends the enhanced channel assignment message (ECAM) over F_CCCH. The MS backs to its active state and operates on one leg mode (i.e., one member in an active set). Then, the MS sends a pilot report message to the BTS over R_DCCH/FCH, because the network requires that the MS to report its radio environment through PSMM once it acquires the traffic channel. This achieves higher throughput than R_REACH.

[0173] Where multi-legs operation is required, there are two options of sending ECAM by the BTS to the MS. Option 1 is that the BTS sends ECAM of multiple members in active set as shown in FIG. 4A . Option 2 is that the BTS sends ECAM of the MS's active set that is necessary to be updated as shown in FIG. 4B . In Option 2, during the active state, the active set can be gradually updated.

[0174] The network can transmit the data burst to an MS in the dormant state. FIG. 5 shows the procedure of the data burst transmission initiated by a dormant MS. Referring to FIGS. 1 and 5 , the data burst transition initiated by the MS will be described.

[0175] The MS (e.g., the MS 121 ) sends a message consisting of a preamble and header (MSG_Type=10) to the BTS (e.g., the BTS 111 ) through the reverse link (R_EACH). The reservation request header is shown in Table V (MSG_TYPE of two bits). The BTS sends back the early acknowledgement message (MSG_Type=01) to the MS over F_CACH. In the embodiment, the format of the Early Acknowledgement Channel Assignment Message (EACAM) shown in Table VI is modified by the location update acknowledgment message shown in Table VIII. The MS sends the preamble and data to the BTS over R_CCCH and the BTS sends data burst acknowledgement message (MSG_Type=11) to the MS over F_CACH. The format of the data burst acknowledgement message is shown in Table IX.

[0176] The network can transmit the data burst to an MS in the dormant state. FIG. 6 shows the procedure of the data burst transmission initiated by the BTS. Referring to FIGS. 1 and 6 , the data burst transition initiated by the BTS will be described.

[0177] The MS (e.g., the MS 121 ) sends a message consisting of a preamble and header (MSG_Type=00) to the BTS (e.g., the BTS 111 ) through the reverse link (R_EACH). The location update message is shown in Table III (MSG_TYPE of two bits). The BTS sends back the location update acknowledgement message (MSG_Type=010) to the MS over F_CACH. In this case, the network is aware of the location of the MS, the network sends a short data burst message to the MS over F_CCCH of the sectors in the “sub-packet data zone” where the MS is. The MS sends the data burst acknowledgment message (MSG_Type=11) to the BTS over R_EACH. The format of the data burst acknowledgment message is shown in Table IX.

[0178] In communication services, zones may be registered to track MSs. Such registration zones are efficient to voice services, but not to packet data services. BTSs need to track MS to a smaller tracking zone to achieve more efficient dormant to active transitions. The present invention may provide a method for tracking zone update to enable a base transceiver station (BTS) to page a mobile station (MS) in a smaller area.

[0179] In order to improve the paging within smaller tracking zones, in accordance with an embodiment of the present invention, sub-packet zone ID is broadcasted in the overhead message. The MS that support the feature reports its location on R-CSCH when it detects a tracking zone change. The service provider configures the size of the tracking zone and all BTSs in the same tracking zone have same zone value. Based on the report from the MSs, the network with the BSC level control can page the MS within the zone where the MS sends the report.

[0180] FIG. 7 shows an example of zones containing user MSs. Referring to FIG. 7 , zones Z 11 , Z 12 and Z 13 belong to the area of one Base Station Controller BSC 1 . Zones Z 21 , Z 22 and Z 23 belong to an adjacent area of another Base Station Controller BSC 2 . Each zone is divided to a plurality of smaller areas: e.g., B 1 , B 2 , B 3 , B 4 and B 5 . Zone Z 13 is adjacent to zone Z 23 and B 1 , B 2 and B 3 belong to zone Z 13 and B 4 and B 5 belong to zone 23 , respectively.

[0181] To perform the tracking zone and the paging shown in FIG. 7 , the following is necessary as CDMA Numeric Information.

[0182] TKZ_ID _s —Tracking zone identifier.

[0183] TKZ_LIST_LEN _s —Number of tracking zone identifier to be maintained in the tracking zone list.

[0184] MAX_NUM_TKZ _s —The maximum number of Radio Environment Report

[0185] Messages that the MS is permitted to transit before disabling tracking zone reporting.

[0186] TKZ_SUP _s —BTS support of tracking zone reporting indicator.

[0187] TKZ_LIST _s —Tracking zone list. It is a list of most recent TKZ_IDs MS have received.

[0188] In the MS in the dormant state, the MS monitors the Paging Channel or the Quick Paging Channel or Forward Common Control Channel/Primary Broadcast Control Channel. The MS can receive messages, receive an incoming call (MS terminated call), initiate a call (MS originated call), cancel a priority access and channel assignment (PACA) call, initiate a registration, or initiate a message transmission.

[0189] The MS may monitor the Quick Paging Channel to determine if it should receive messages from the Paging Channel or Forward Common Control Channel.

[0190] Upon entering the Mobile Station Dormant State from the Mobile Station Initialization State, the MS shall perform the following:

[0191] If SR1_BCCH_NON_TD_INCL _S is equal to ‘1’, or if SR1_TD_INCL _s is equal to ‘1’ and the MS supports the transmit diversity mode specified by SR1_TD_MODE _s , or if the MS supports Spreading Rate 3 on the common channel and SR 3 _INCL _s is equal to ‘1’, the MS shall perform the following:

[0192] Set its Primary Broadcast Control Channel code channel to BCCH _s ,

[0193] Set the Primary Broadcast Control Channel data rate as determined by BRAT _s ,

[0194] Set the Primary Broadcast Control Channel code rate as determined by BCCH_CODE_RATE _s ,

[0195] Set SLOTTED _s to YES if T_SLOTTED _s is equal to ‘00000000’ or if the MS does not support the slotted timer; otherwise, enable the T _{MS — Slotted} timer with the duration specified by T_SLOTTED _s and set SLOTTED _s to NO, and

[0196] Perform common channel supervision. The initial parameter is set up when the MS enters the dormant state from the MS initialization state.

[0197] Otherwise, the MS shall perform the following:

[0198] Set its code channel to PAGECH _s ,

[0199] Set the Paging Channel data rate as determined by PRAT _s ,

[0200] Set SLOTTED _s to YES if T_SLOTTED _s is equal to ‘00000000’ or if the MS does not support the slotted timer; otherwise, enable the T _{MS — Slotted} timer with the duration specified by T_SLOTTED _s and set SLOTTED _s to NO, and

[0201] Perform Paging Channel supervision.

[0202] Upon entering the Mobile Station Dormant State from the Mobile Station Control on the Traffic Channel State, the MS shall perform all of the following:

[0203] Set SLOTTED _s to YES if T_SLOTTED _s is equal to ‘00000000’ or if the MS does not support the slotted timer, otherwise, enable the T _{MS — Slotted} timer with the duration specified by T_SLOTTED _s and set SLOTTED _s to NO.

[0204] Perform common channel supervision.

[0205] If TKZ_ENABLED is YES and the tracking zone update timer is not enabled, the MS shall perform the following:

[0206] Initialize the tracking zone list TKZ_LIST _s with the length of TKZ_LIST_LEN _s and add TKZ_ID _s to the TKZ_LIST _s ,

[0207] Set the tracking zone update timer to infinity if TKZ_UPDATE_PRD _s is equal to ‘1111’; otherwise, the MS shall set the tracking zone update timer to 2 ^{TKZ _— UPDATE _— PRD _S +6} seconds, then

[0208] Enable the tracking zone update timer.

[0209] If REDIRECTION _s , PACA _s , and NDSS_ORIG _s are equal to disabled, the MS may exit the Mobile Station Dormant State at any time and enter the System Determination Substate of the Mobile Station Initialization State with a reselection indication.

[0210] While in the Mobile Station Dormant State, the MS shall perform the following procedures:

[0211] The MS shall perform Paging Channel or Forward Common Control Channel monitoring procedures.

[0212] The MS shall perform message acknowledgment procedures with the received forward message from the BTS.

[0213] If the key set-up timer expires or has expired, the MS shall set REG_SECURITY_RESYNC (formerly called REG_ENCRYPT_RESYNC) to YES and the MS shall go to the System Determination Substate with an encryption/message integrity failure indication.

[0214] If TKZ_ENABLED is set to YES, the MS shall perform the following:

[0215] If TKZ_ID _s is not equal to any entry in TKZ_LIST _s , the MS shall send a Radio Environment Report Message by performing the Mobile Station Message Transmission Operation.

[0216] If TKZ timer of any entry in TKZ_LIST _s has expired, the MS shall delete that entry.

[0217] If the tracking zone update timer expires, the MS shall disable the tracking zone update timer and set TKZ_ENABLED to NO.

[0218] Upon expiration of the radio environment report timer, the MS shall disable the timer and set RER_ENABLED (the radio environment report) to NO. If TKZ_INFO_INCL _s is equal to ‘1’, then the MS shall perform the following:

[0219] Set TKZ_ENABLED to YES.

[0220] Initialize the tracking zone list TKZ_LIST _s with the length of TKZ_LIST_LEN _s and add TKZ_ID _s to the TKZ_LIST _s ,

[0221] Set the tracking zone update timer to infinity if TKZ_UPDATE_PRD _s is equal to ‘1111’; otherwise, the MS shall set the tracking zone update timer to 2 ^{TKZ _— UPDATE _— PRD _S +6} seconds, then

[0222] Enable the tracking zone update timer.

[0223] Whenever an Extended System Parameters Message is received on the Paging Channel, the configuration message sequence number, CONFIG_MSG_SEQ _r , shall be compared to that stored in EXT_SYS_PAR_MSG_SEQ _s . If the comparison results in a match, the MS may ignore the message. If the comparison results in a mismatch, then the MS shall process the remaining fields in the message as follows.

[0224] The MS shall store MS initiated position location determination supported indicator (MS_INIT_POS_LOC_SUP_IND _s =MS_INIT_POS_LOC_SUP_IND _r ).

[0225] If the MS supports tracking zone, the MS shall store tracking zone supported indicator (TKZ_SUP _s =TKZ_SUP _r ).

[0226] If TKZ_SUP _s is equal to ‘1’, the MS shall store the tracking zone identifier (TKZ_ID _s =TKZ_ID _r ).

[0227] If TKZ_ENABLED is YES and the tracking zone update timer is not enabled, the MS shall perform the following:

[0228] Initialize the tracldng zone list TKZ_LIST _s with the length of TKZ_LIST_LEN _s and add TKZ_ID _s to the TKZ_LIST _s ,

[0229] Set the tracking zone update timer to infinity if TKZ_UPDATE_PRD _s is equal to ‘1111’; otherwise, the MS shall set the tracking zone update timer to 2 ^{TKZ _— UPDATE _— PRD _S +6} seconds, then

[0230] Enable the tracking zone update timer.

[0231] Whenever an ANSI-41 System Parameters Message is received, the configuration message sequence number, CONFIG_MSG_SEQ _r , shall be compared to that stored in A41_SYS_PAR_MSG_SEQ _s . If the comparison results in a match, the MS may ignore the message. If the comparison results in a mismatch, then the MS shall process the remaining fields in the message to store parameters.

[0232] The MS shall store the following parameters:

[0233] Configuration message sequence number (CONFIG_MSG_SEQ _s =CONFIG_MSG_SEQ _r , A41_SYS_PAR_MSG_SEQ _s =CONFIG_MSG_SEQ _r )

[0234] Home registration indicator (HOME_REG _s =HOME_REG _r )

[0235] If MSG_INTEGRITY_SUP _r is equal to ‘1’ and SIG_INTEGRITY_SUP_INCL _r is equal to ‘1’, the MS shall store the message integrity algorithms that the BTS supports (SIG_INTEGRITY_SUP _s =SIG_INTEGRITY_SUP _r ); otherwise, the MS shall set SIG_INTEGRITY_SUP _s to ‘00000000’.

[0236] The MS shall also store the following parameters if the MS is not in the Origination Attempt Substate or Page Response Substate:

[0237] System identification (SID _s =SID _r )

[0238] Network identification (NID _s =NID _r )

[0239] Registration zone (REG_ZONE _s =REG_ZONE _r )

[0240] If DIST_REG_INCL is equal to ‘0’, then the MS shall set REG_DIST equal to ‘00000000000’.

[0241] If the MS supports tracking zone, the MS shall store tracking zone supported indicator (TKZ_SUP _s =TKZ_SUP _r ). If TKZ_SUP _s is equal to ‘1’, the MS shall store the tracking zone identifier (TKZ_ID _s =TKZ_ID _r ).

[0242] If TKZ_ENABLED is set to YES and the tracking zone update timer is not enabled, the MS shall perform the following:

[0243] Initialize the tracking zone list TKZ_LIST _s with the length of TKZ_LIST_LEN _s and add TKZ_ID _s to the TKZ_LIST _s ,

[0244] Set the tracking zone update timer to infinity if TKZ_UPDATE_PRD _s is equal to ‘1111’; otherwise, the MS shall set the tracking zone update timer to 2 ^{TKZ _— UPDATE _— PRD _S +6} seconds, then

[0245] Enable the tracking zone update timer.

[0246] If the MS supports the Mobile Station Message Transmission Operation, the operation will be performed when the user directs the MS to transmit a Data Burst Message, or when the MS detects a change in the hook status since the last time when the MS sent hook status information and the MS supports the Device Information Message on the R-CSCH, or when the MS detects that a Radio Environment Report Message is required to be transmitted on the R-CSCH.

[0247] If the MS supports the Mobile Station Message Transmission Operation, the MS shall set CURR_ACC_MSG_SEQ to NULL.

[0248] If the MS supports the Mobile Station Message Transmission Operation and the operation is performed when the user directs the MS to transmit a Data Burst Message, the MS shall enter the Update Overhead Information Substate of the System Access State with a message transmission indication within T _33m seconds.

[0249] If the MS supports the M