HK1078717B - Method for coordinating paging occasions on a common paging channel - Google Patents

Description

Method for coordinating call events on a shared call channel

Technical Field

The present invention relates generally to the field of wireless communications. More particularly, the present invention relates to mechanisms for providing call services in a cellular network.

Background

In conventional third generation (3G) cellular networks, point-to-point (PtP) and point-to-multipoint (PtM) paging mechanisms must provide efficient use of radio paging resources while still maintaining low User Equipment (UE) power consumption. Calls are used to establish connections and activate transmissions. For peer-to-peer services, a call signal transmitted to a ue is associated with a unique identifier (unique identity) assigned to the ue. The user equipment is expected to be in a passive call state for a considerable period of time waiting for a call indication. Power consumption when the user equipment is in the call state must be minimized. To achieve this, paging occasions are scheduled in the user equipment and the network. This allows the user equipment to minimize transmission and reception processing between call events, which results in reduced power consumption and a corresponding increase in battery life.

For point-to-point services, the physical paging channel and paging occasion are determined from unique identifiers for each ue. The motivation for using the ue identifier is to provide a substantially equal allocation of call transmission for all call resources.

System information block type 5(SIB5) defines the shared channel to be used in "idle" mode, while system information block type 6 defines the shared channel to be used in "connected" mode. In a cell, one or more call transport channels (PCHs) may be established. Each secondary shared control physical channel (SCCPCH), labeled with system information to the ue, is carried up to a paging transport channel. Thus, for each defined paging transport channel, there is a unique associated Paging Indicator Channel (PICH) that is also labeled. When more than one paging transport channel and associated paging indicator channel are defined in system information block type 5 or system information block type 6, the UE selects the SSC from those listed in system information block type 5 or system information block type 6 based on the International Mobile Subscriber Identifier (IMSI) as follows:

the selected secondary shared control physical channel pointer is IMSI mod K;

equation (1)

Where K is equal to the number of listed secondary cpchs carrying a paging transport channel (i.e., the secondary cpchs carry only Forward Access Channels (FACHs) that should not be counted — these secondary cpchs are labeled from 0 to K-1 in the order they appear in system information block type 5 or system information block type 6.

Therefore, the user equipment selects a physical paging channel from the paging channel list according to the number of selected paging channels as follows:

the number of the selected calling channels is equal to the user equipment identifier mod K;

equation (2)

Where K is the number of physical paging channels present in the cell. Equation (2) can randomly assign the ue between paging channels.

The user equipment may use Discontinuous Reception (DRX) in idle mode or connected mode to reduce power consumption. When discontinuous reception is used, the ue only needs to monitor a Paging Indicator (PI) for a paging event every drx cycle. The user equipment may be attached to different core network domains with different Core Network (CN) domain specific discontinuous reception cycle lengths. The ue may store each of the cn domain-specific drx cycle lengths for each cn domain to which the ue is attached, and use the shortest of these drx cycle lengths. The length of the discontinuous reception cycle used for the universal radio access network (UTRAN) connected mode is the shortest of:

(1) a global radio access network discontinuous reception cycle length; or

(2) Any stored core network domain specific discontinuous reception cycle length without signaling setup for the core network domain to which the user equipment is only attached.

The UE determines the paging occasion using the IMSI, the PCCH carrying the paging transport channel (K), the cell System Frame Number (SFN), Np, frame offset, Paging Block Periodicity (PBP), and discontinuous reception cycle length.

For Frequency Division Duplex (FDD), Np is the number of intra call fingers and the frame offset is equal to zero. In fdd, the ue monitors its paging indicator in the paging indicator channel by the number of cell system frames given by the paging event.

For Time Division Duplex (TDD), Np is the number of paging fingers within a paging block, and the paging finger channel frame offset value is given in the system information.

In tdd, the ue monitors the paging indicator in the paging block given by the paging event. The call event gives the cell system frame number of the first frame of the call block.

The call event value is determined as follows:

call event { (IMSI div K) mod (DRX cycle length div PBP) } PBP + n DRX cycle length + frame offset;

equation (3)

Wherein n is 0, 1, 2 as long as the cell system frame number is lower than its maximum value. The physical paging indicator within the paging occasion that the ue should read is also determined based on the international mobile subscriber identity.

The call pointer used is calculated using the following formula:

PI ═ DRX pointer mod Np; equation (4)

Wherein DRX pointer is IMSI div 8192.

In TDD mode, the paging message reception event is calculated using the following formula:

paging message reception event + NPICH + NGAP + { (DRX pointer mod Np) mod NPCH }. 2;

equation (5)

Where the NPICH value is the number of frames for the paging pointer channel and is equal to the paging pointer channel reception length given in the system information. The NGAP value is the number of frames between the last frame of the paging indicator channel carrying the paging indicator of the paging event and the first frame of the paging indicator channel carrying the paging indicator of the paging event. The NPCH value is the number of paging groups. The NPCH and NGAP values are given in the system information.

Thus, the UE can determine the paging occasions on the selected paging indicator channel that are identified by the unique radio frame number according to:

the number of call event frames ═ number of (ue identifier div K) mod (DRX cycle length) + n (DRX cycle length);

equation (6)

Wherein DRX is discontinuous reception.

Equation (6) identifies the number of frames in each drx cycle and then applies to each subsequent cycle.

In a time division duplex system, paging block periodicity and frame offset are also considered. The motivation for using the ue identifier is to provide an approximately equal allocation of call transmission of all call resources.

Fig. 1 depicts that user equipment may have to receive individual paging occasions and physical paging channels to receive user group and user equipment specific paging. In FIG. 1, "UP" 105 represents a user equipment specific call event; "GP" 110 represents a subscriber group call event; and "X" 115 represents a user equipment in discontinuous reception. A more efficient way of performing group calls is desirable.

Disclosure of Invention

The present invention defines a ue paging mechanism that synchronizes user-specific and user-group paging events to support broadcast and multicast services. The paging mechanism coordinates paging occasions on the common paging channel for user-specific and user-group. The present invention can apply point-to-multipoint group paging services to similar paging channels and event determination logic, such that equations (2) and (6) above can be replaced by a shared subscriber group identifier. This facilitates the association of a paging channel and paging event group with a particular point-to-multipoint user group. An advantage of point-to-multipoint user group calls is that the physical resources for calls within each cell are only required once per user group rather than once per user in the group.

Drawings

A more complete understanding of the present invention can be obtained from the following description of the preferred embodiments and the accompanying drawings, in which:

FIG. 1 is a block diagram depicting conventional standalone user-specific and user group paging events on individual physical paging channels;

FIG. 2 is a block diagram depicting coordination of user-specific and user-group paging events on a common paging channel in accordance with the present invention;

FIG. 3 is a flowchart of method steps for synchronizing paging services including paging a plurality of subscribers using temporary identifiers, in accordance with one embodiment of the present invention;

FIG. 4 is a flow chart of method steps for a call subset including a plurality of subscribers, in accordance with another embodiment of the present invention; and

fig. 5 is a Radio Network Controller (RNC) for coordinating user-specific and user-group call events.

Detailed Description

The present invention may define a ue paging mechanism in a wireless system that may synchronize user-specific and user-group paging events by forcing paging transport channels and paging events to be the same, so that users may save battery and paging channels are used more efficiently. When the paging transmission channel is a paging event during a particular paging interval, the paging mechanism must wake up only once during that interval to find a paging message. Since the paging mechanism does not have to continuously monitor the paging transmission channel individually for point-to-point and point-to-multipoint paging events.

The user equipment is hereafter a wireless transmit/receive unit (WTRU) including, but not limited to, a mobile station, a fixed or mobile subscriber unit, a pager, or any other type of device capable of operating in a wireless environment.

According to the present invention, a particular channel and call events on that channel are always known to the UE and the network. As shown in fig. 2, a mechanism for coordinating user-specific and user-group paging events on a common paging channel is disclosed. In this figure, the term UP is for a user equipment specific call event; GP is the user group call event and X is the user equipment in discontinuous reception mode.

Referring to FIG. 3, a process 300 according to the present invention is shown. Coordination between the shared identifier management function or the user group and user specific identifier management functions may provide identifiers that correlate the shared paging channel with paging occasions. According to the process 300, the new temporary ue-specific identifier is assigned to the performance of the point-to-multipoint service for all ues in the ue group (step 305). The temporary user-specific identifiers may associate the same physical paging channel with paging occasions associated with the group paging.

In step 310, the ue selects a physical paging channel from the list of paging channels. The paging channel is selected according to the following:

the number of the selected calling channels is equal to the user equipment identifier mod K;

equation (7)

Where K is the number of physical paging channels present in the cell.

The user equipment may then determine a paging event on the selected paging indicator channel identified by the unique radio frame number (step 315), wherein:

call event frame number ═ temporary identifier div K) mod (DRX cycle length) + n (DRX cycle length);

equation (8)

The paging channel and paging occasion may continue to be determined from the low order bits assigned the identifier. In this case, the high order bits may be used to differentiate ue-specific and ue group call event causes.

According to the present invention, the UE has a shared paging occasion for both the UE-specific and the PPP UE group paging. Without increasing the number of call events to perform the point-to-multipoint service. Thus, there is no need to increase the power consumption for performing the point-to-multipoint service.

When a paging event occurs, the UE checks the UE-specific paging indicator and the PPP UE group indicator. Depending on the received identifier, the call type is known to the user equipment. Alternatively, a shared identifier may be provided and a ue-specific or point-to-multipoint group call in the associated origination cause may be determined. Thus, when the ue reads its paging occasion, it can read the called identifier and the paging cause, either of which can indicate the service type (point-to-point or point-to-multipoint).

Depending on the maximum number of users per paging occasion, it may be necessary to allocate user-specific paging occasions to groups of users across more than one physical paging channel and paging occasion. For large groups of point-to-multipoint users, point-to-multipoint identifiers are provided to keep individual paging occasions from saturating. Each point-to-multipoint identifier is associated with a subset of calls within the point-to-multipoint user group.

The subset paging indicator is generated for each physical paging channel and associated paging occasion required by the ptm user group. When a group call is required, a subset paging indicator is applied to its associated paging channel and paging occasion.

As described above, the ue identifier is used to determine paging channels and paging occasions. The present invention provides a call for point-to-multipoint service for several users. Typically, these users have different paging channels and different events. The invention aims to create an equal distribution of call events throughout the call transport channel, so that physical resources are efficiently allocated. Otherwise, if the call is not equally allocated, there will be periods when the call transport channel is not fully utilized. Excessive call generation during a particular paging event will cause paging overflow and a loss of opportunity to page the ue for the paging event.

The user identifier is used to create an equal allocation. The present invention minimizes the total number of calls for point-to-multipoint services provided to a number of users having user equipment that must wake up and recognize calls. For example, if fifty users are served point-to-multipoint, it is not desirable to call all fifty users individually. The present invention can receive the service by performing a set of call events generated by the network using a single set of call events used to wake up the user equipment of the fifty users.

In the preferred embodiment of the present invention, the point-to-multipoint service is synchronized such that the temporary identifier is used to synchronize paging occasions of the point-to-point and point-to-multipoint services. Temporary identifiers are generated for point-to-point and point-to-multipoint services, or a shared identifier may be established for both (e.g., when the call cause or some other non-high order bit method is used to determine point-to-point and point-to-multipoint). Only the low order bits of the paging indicator or ue indicator are used to determine what the paging occasion is. The high order bits may be used to determine whether point-to-point and point-to-multipoint services are used. When the user equipment receives a call, a match on the user equipment specific call identifier occurs. Thus, not only is it necessary to find out the paging occasions on the paging channels assigned to the UE, the paging indicators that indicate whether the service is point-to-point or point-to-multipoint by the value signaled at the paging indicator are also checked when the paging occasions are detected. Alternatively, there is also a call cause received with the call identifier. The call cause may be signaled to the user whereby the shared identifier may be identified and the associated call cause may be examined to determine whether the service is point-to-point or point-to-multipoint.

For a very large number of users in a point-to-point group (e.g., 1000 users), when a particular paging occasion is forced to calibrate for a point-to-multipoint paging occasion, too many point-to-point paging occasions or users may drop out of the same paging occasion, resulting in saturation of the paging occasion. Further, the subscriber allocation for all available call events is missed. Thus, it is not expected that all call events for a large number of users will be aggregated on a single call event.

Referring to fig. 4, the ue may select a physical paging channel from a list of paging channels in accordance with process 400 (step 405). Paging occasions are set by keeping track of paging channels and paging occasion assignment logic. More than one point-to-multipoint call event is created for a very large group. The group of users associated with the point-to-multipoint group are associated with individual ones of the point-to-multipoint call events. For example, if there are currently 1000 users but only 100 users allowed to associate with any paging occasion, 10 paging occasions with 100 users associated with each other are established, so that the ue associated with the 100 users will wake up and look for the point-to-point and point-to-multipoint identifiers to determine which service is activated (step 410). Because it is used for point-to-multipoint services, the number of user equipments per paging occasion must be limited, and paging channels and paging occasions are not equally allocated. Of the 1000 users listening, 100 groups will be focused on a particular call event, so when the point-to-multipoint service is established, a 10 call is made, one for a group of 100 users (step 415).

Referring to fig. 5, the rnc 500 may determine how paging occasions are set by keeping track of paging channels and paging occasion assignment logic. The rnc 500 includes a cpich management function device 505, a paging channel tracking device 510, a paging event assignment logic device 515 and a paging channel generation device 520. The shared identifier management function device 505 may provide identifiers associated with the shared paging channel and paging occasions. The paging channel tracking device 510 can set the paging occasion by keeping track of the paging channel. The paging event assignment logic device 515 keeps track of the paging event assignment logic. The paging channel generating means 520 may associate a user group of the point-to-multipoint group with an individual of the point-to-multipoint paging event.

While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the invention described above.

Claims (3)

1. A method of calling a plurality of users in a wireless communication system, comprising:

(a) selecting a physical paging channel from the paging channel column; and

(b) determining a specific paging occasion on the selected paging channel, the paging occasion being identified by a unique radio frame number, wherein the temporary identifier is used to synchronize paging services for both point-to-point and point-to-multipoint services.

2. The method of claim 1 wherein the number of selected paging channels is substantially equal to the temporary identifier mod K, where K is the number of physical paging channels present.

3. The method of claim 2, wherein the number of frames is substantially equal to

(temporary identifier div K) mod (discontinuous reception cycle length) + n (discontinuous reception cycle length), where n is an integer greater than or equal to 0.