JP2003529232A - Cell Broadcast in Hybrid GSM / CDMA Network - Google Patents

Abstract

Kind Code: A1 In a GSM mobile wireless communication system, a method of broadcasting a message over a CDMA air interface comprises transmitting a message to a base station substantially according to a GSM cell broadcast service protocol and moving over the CDMA air interface. Including sending a message to the station. The messages are transmitted substantially according to the CDMA transmission standard, preferably the IS-95B standard.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to wireless communications, and more particularly to modern cellular telephone networks.

[0002]

[Prior art]

The Global System for Mobile Communications (GSM) is used in cellular telephone networks in many countries around the world. Existing GSM networks are based on Time Division Multiple Access (TDMA) digital communication technology. GSM offers a useful range of network services and standards.

One of these GSM network services is short message service-
Cell Broadcast (SMSCB), which distributes short messages from a Cell Broadcast Center (CBC) through a Base Station Subsystem (BSS) in the network to subscriber units, or mobile stations (MS). SM
SCB messages come from a variety of sources such as traffic and weather reports. These messages are broadcast over a dedicated cell broadcast channel (CBCH) to a defined geographical area known as the cell broadcast area without requiring an acknowledgment from the MS. The message is received by the MS only in idle mode (ie no telephone call is in progress). The SMSCB and associated interfaces, protocol stacks, and message formats are specifically GSM standards 02.03, 03.41, 03.
49 and 04.12, which are incorporated herein by reference. However, it should be noted that there is no mandatory protocol between the CBC and BSS defined by the GSM standard. Rather, the interface protocol remains to be determined by the operators of network and cell broadcast services based on the building blocks defined by the 03.41 standard.

Code Division Multiple Access (CDMA) is an improved digital communication technology that uses direct sequence spread spectrum modulation technology, which is a more reliable fade-free link between cellular telephone subscribers and base stations. Together, it provides more efficient use of radio bandwidth than TDMA. The leading CDMA standard is TIA / EIA-95 published by the Telecommunications Industry Association (TIA), which is incorporated herein by reference. In the context of this application and in the claims, this standard is referred to as IS-95 and is commonly known in the cellular communications industry by this name. TIA / EIA-95-B (hereinafter IS-95
Recent versions of the standard, known as B), have state-of-the-art network capabilities including procedures for broadcasting messages over paging channels that are monitored and received by compatible MSs.

PCT patent application PCT / US96 / 20764 is US patent application serial number 0
8 / 575,413, which is entitled "Wireless Communication System Communication System Using CDMA Radio Frequency Signal Modulation With GSM A Interface Communication Network Protocol", filed December 20, 1995, and is hereby incorporated by reference. Assigned to the assignee, both incorporated herein by reference, and the CDM
A air interface (ie basic RF communication protocol)
A wireless communication system implementing SM network services and protocols is described. Using this system, the TDM of the existing GSM network
A base station (BSS) and at least some of the subscriber units have a corresponding CD
Replaced or supplemented by MA devices. CDMA BS in this system
The S is adapted to communicate with a GSM mobile switching center (MSC) through a standard GSM A interface. Thus the core of GSM network services is maintained and the transition from TDMA to CDMA is transparent to the user.

A hybrid cellular communication network including both GSM and CDMA components is described in PCT patent publications WO 95/24771 and WO 96/21999 and also in a paper by Tscha et al. 2 "International Conference Bulletin, pp 181-185,"
"Subscriber Signaling Gateway between CDMA Mobile Stations and GSM Mobile Switching Centers", which are incorporated herein by reference. All of these publications are SM in such hybrid networks.
It does not deal with issues related to supporting short message or cell broadcast services such as SCB.

[0007]

[Problems to be Solved by the Invention]

It is an object of the present invention to provide a method and apparatus for use in a mixed GSM / CDMA cellular communication network.

It is another object of some aspects of the invention to provide a method and apparatus that enables the implementation of GSM cell broadcast services over a CDMA air interface.

[0009]

[Means for Solving the Problems]

In a preferred embodiment of the present invention, a mixed GSM / CDMA cellular communication system includes both TDMA and CDMA base stations (BSS), which are G
Contrast with the Cell Broadcast Center (CBC), which is based on the SM standard.
This type of system is generally described in US patent application serial number 09 / 119,717, filed July 20, 1998, entitled "Base Station Handover in Hybrid GSM / CDMA Networks", This US patent application is assigned to the assignee of the present application and is hereby incorporated by reference. A subscriber unit in a network is referred to herein as a mobile station (MS), TDMA
It is preferable to be able to communicate with both types of base stations by switching appropriately between the and CDMA air interfaces. Since the GSM network protocol is used over both types of air interface, the MS can
M, whether communicating with an A BSS or a CDMA BSS
S receives the short message broadcast from GSM CBC. Therefore, the present invention does not compromise the CBC's ability to pertain to networks that broadcast messages to virtually any MS based on the GSM standard, and substantially eliminates other modifications required to existing infrastructure. It enables CDMA BSS and MS to be integrated into the infrastructure of GSM networks without having to

In some preferred embodiments of the present invention, GSM Short Message Service-Cell Broadcast (SMSCB) messages are broadcast to MSs over a CDMA air interface using a CDMA paging channel. The message is preferably broadcast according to a broadcast procedure over the paging channel defined by the IS-95B standard.

Therefore, according to a preferred embodiment of the present invention, there is provided a method of broadcasting a message in a GSM mobile wireless communication system through a CDMA air interface, the method being substantially in accordance with a GSM cell broadcast service protocol. Includes communicating messages to stations and sending messages to mobile stations over the CDMA air interface.

Sending the message is substantially in accordance with the CDMA transmission standard.
Most preferably it comprises sending the message according to IS-95B.

Sending the message preferably includes sending the message over a paging channel, and sending the message includes directing the message to one or more specific cells.

In a preferred embodiment, sending the message comprises sending the message such that it is more likely to be received by the mobile station while it is operating in slotted mode. Most preferably by sending a subsequent broadcast page. Sending the broadcast page preferably includes sending the page in a predetermined slot being monitored by the mobile station in a periodic broadcast paging cycle. Optionally, the method includes sending a schedule message that includes information about one or more broadcast pages to be sent in a schedule period that includes one or more periodic broadcast paging cycles.

Sending the message comprises sending the single message multiple times substantially in accordance with the GSM cell broadcast command, and sending the single message comprises assigning a broadcast address to the message, whereby the mobile station The second message is preferably discarded when the second message is received that has the same broadcast address as the first message, which is the earlier message. Sending a single message multiple times preferably includes sending the message repeatedly at a repeat frequency determined in response to the cell broadcast command.

Sending a message is a GSM cell broadcast message IS-
It is further preferred to include encapsulation in 95 messages.

Communicating the message preferably comprises receiving the message from the cell broadcast center.

In a preferred embodiment, sending the message includes sending a message header that includes a message identifier field indicating characteristics of the message,
The mobile station decides whether to decode or discard the message in response to the characteristic.

According to a preferred embodiment of the present invention, there is also provided an apparatus for broadcasting a short message from a cell broadcast center through a CDMA air interface, the apparatus comprising a base station subsystem, which is essentially a GSM cell broadcast. It receives a message from the cell broadcast center according to the service protocol and sends the message to the mobile station through the CDMA air interface.

The base station subsystem preferably transmits messages substantially according to the CDMA transmission standard, most preferably IS-95B.

The base station subsystem preferably sends a message over the paging channel and directs the message to one or more specific cells.

The base station subsystem preferably sends a message so that the mobile station is more likely to be received by the mobile station while operating in slotted mode, and before sending the message, the base station subsystem The system transmits pages in predetermined slots that are monitored by mobile stations in periodic paging cycles.

The base station subsystem sends the single message multiple times substantially in accordance with the GSM cell broadcast command, and the base station subsystem sends the message at a repetition frequency determined in response to the cell broadcast command. It is more preferable to repeat. The base station subsystem assigns a broadcast address to the message so that when the mobile station receives a second message that has the same broadcast address as the earlier message, the first message, the second message is discarded. More preferably.

The invention will be more fully understood from the following detailed description of the preferred embodiments of the invention in conjunction with the drawings.

[0025]

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, which is a schematic block diagram of a hybrid GSIVI / CDMA cellular communication system 20 according to a preferred embodiment of the present invention. The system 20 is built around a public land mobile network (PLMN) 22, which is based on the GSM communication standard known in the art and briefly described above. Infrastructure for such networks already exists and is widely used in many countries, and the present invention relates to such networks without requiring major changes to existing switching infrastructures. It has the advantage of gradually introducing CDMA services.

PLMN 22 includes at least one mobile service switching center (MSC).
24), or possibly a large number of such centers (only one MSC is shown here for clarity), which controls network operations within the geographical area. Among other functions, the MSC 24 is capable of subscriber unit location registration and subscriber unit handover between base stations, and PLMN 22 to the public switched telephone network (PSTN) and / or packet data network (PSN). PDN) 48. PLM
The N also has a network management center (NMC) 26 and a cell broadcast center (CBC) 28. Further aspects of system 20 and details regarding mobile station (MS) 40 in the system are further described in the aforementioned US and PCT patent applications.

The system 20 includes a plurality of MSs 40 that communicate with the PLMN 22 by a plurality of base station subsystems (BSSs) 30 and 32 over a wireless RF link at one or more allowed cellular communication frequencies. connect. The MS 40, also known as a subscriber unit, is preferably capable of communicating with both the GSM BSS 30 using the standard GSM TDMA wireless communication protocol and the CDMA BSS 32 using the CDMA based communication methods described below.
For clarity, MS40, GSM BSS30 and CDMA BSS32
Although only one of each of these is shown in FIG. 1, it should be understood that in practice system 20 typically includes a plurality of each of these system components.

Communication between the CDMA BSS 32 and the MS 40 uses a CDMA radio “air interface”, which is preferably based on the IS-95 standard for CDMA communication, which is the TIA / EIA-95 standard. Most preferred is -B, which is incorporated herein by reference and makes the necessary modifications as described herein. The BSS 32 is built around a base station controller (BSC) 34, which controls and communicates with a number of base station transceivers (BTS) 36. Each BTS transmits an RF signal to the MS 40 and receives an RF signal from the MS 40 when the MS is within a geographical area, or cell, covered by a particular BTS. On the other hand, when the MS 40 is in a cell served by the GSM BSS 30, the MS communicates with the BSS 30 through the GSM / TDMA air interface to the GSM / TDMA BTS (not shown in the figure for simplicity). It is preferable.

Both the GSM BSS 30 and the CDMA BSS 32 communicate with the MSC 24 substantially according to the GSM standard, ie, through the GSM Standard A interface, which is further described in the above-mentioned US and PCT patent applications.
It is controlled by the MSC 24. BSS 32 is a wireless operation and maintenance center (OM
CR) 38, which communicates with the NMC 26 through the GSM standard Q3 interface.

The BSC 34 communicates with the CBC 28 to receive short messages to be broadcast over the air interface, based on the GSM SMSCB standard mentioned above. One CBC 28 is typically multiple BSSs
CDMA BSS such as BSS32 connected to these BSSs.
, GSM / TDMA BSS such as BSS30. C
The BC receives short messages for broadcasting from some cell broadcasting entities (not shown), such as the Weather and Traffic Report Center, as described in the GSM specification.

The CBC 28 is capable of managing short messages in cell broadcasts and issues commands to the BSC 34 (and other BSCs) including:

Assign a serial number to the identifier of the message as specified by GSM standard 03.41. The serial number is included in the header of each message (further described below with reference to FIG. 3). This is generally
It contains fields that identify the geographic scope of the message, a message code to distinguish between messages of the same type from the same source, and an update number. -Modify or delete messages held by BSC. Initiate the broadcast by sending a cell broadcast message to the BSC. Based on GSM standard 03.41, it is necessary to pad the message to a length of 82 octets. Determine the set of cells or BTSs in which the message should be broadcast and indicate the geographical extent of the message. The determined cell or BTS list is BS
Informed to C, BSC distributes the broadcast accordingly. -Determine when to start broadcasting the message. -Determine when the message broadcast should end and command the BSC accordingly. -Determine the rate at which the message broadcast should be repeated. -Determine the cell broadcast channel on which the message should be broadcast.

The BSC 34 performs the following functions with respect to the CBC 28. -Receive and interpret cell broadcast commands. -Remember cell broadcast messages. -Schedule messages for CDMA paging channels, as described further below. Display this to the CBC when the required message repetition rate cannot be achieved, eg when the required rate is too high. -Acknowledge that the CBC command execution was successful. C when the command cannot be understood or the command cannot be executed
Report to BC. Route the cell broadcast message to the appropriate BTS, preferably using a commanded paging procedure, as described further below. -Send cell broadcast service (CBS) information to each BTS. -Optionally generate a schedule message to indicate the intended schedule for transmission, as described further below.

When the message delivered from BSC 34 to CBC 28 is suitable for multiple cells, it is preferred that the message is delivered only once with a list of cells to which the message applies.

The MS 40 comprises a mobile device (ME) 42, which is either two radio transceivers, one configured for TDMA operation and one configured for CDMA operation, or dynamically switched between TDMA and CDMA. It is preferable to include any one of the transceivers that can be The MS includes mobile terminals (MT), which support terminal equipment (TE) 46 for voice and data input / output.
In addition, the MS 40 is a subscriber identification module (SIM) according to the GSM standard.
) 44, which is substantially transparent to the CDMA air interface and is independent of this interface.
Used in authenticating a zero user identifier. Although the preferred embodiment has been described with reference to a MS40 having dual CDMA / TDMA air interface compatibility, the principles of the present invention may be applied to systems using mobile stations that are only CDMA compatible or with necessary modifications. It will be appreciated that the same applies to other systems using the GSM network standard.

The MS 40 receives the cell broadcast message sent by the BTS 36 from the BSC 34. Generally, the TE 46 is used to display messages in alphanumeric format as is known in the art. In addition, MS40 is 2
It has the following capabilities for 5 cell broadcast messages:

• Identify and discard messages with a message identifier that indicates that the subject matter of the message is not of interest to the subscriber using the MS. Ignore already received repeat broadcast messages (ie the message broadcast address has not changed). • ME42 and TE when such an interface is supported
46 to send a message through the R interface.

Referring now to FIG. 2, FIG. 2 illustrates a BS according to a preferred embodiment of the present invention.
FIG. 6 is a schematic block diagram illustrating a protocol stack used to carry SMSCB teleservice messages between CBC 28 and MS 40 through S32. The protocol shown in the figure uses the paging channel broadcast procedure between BSS and MS specified by the IS-95B standard to provide GSM S
Based on the MSCB standard, it allows a substantially unmodified GSM CBC to convey a short message to the MS 40.

The cell broadcast message is transmitted from the CBC 28 to the BSC 34 through the CBC-BSC interface. The CBC-BSC interface generally follows the GSM specification. As noted above, the protocol implemented in this interface is a matter to be agreed between operators of CBC and PLMN 22 based on the basic elements defined in GSM standard 03.41. As shown in FIG. 2, the stack is a GSM standard 03.4.
Preferably, one of the sample protocol stacks provided in Section 9 is followed.

The GSM primitives defined by the 03.41 standard are generally received and interpreted by the BSC 34 in accordance with the standard, but to accommodate IS-95B broadcast procedures over the paging channel. There are some exceptions needed. The GSM standard defines two types of cell broadcast channels (CBCH).
), Both basic and extended channels are supported, but both channels are mapped to the same CDMA paging channel. Furthermore, the GSM specification is 5
While defining a maximum of 20 repetition frequencies for cell broadcast messages as once per 1 × 8 TDMA frame (1.883 seconds), the maximum repetition frequency for a CDMA air interface according to IS-95B is a periodic broadcast paging cycle. It is once for each and corresponds to a minimum of about 2.8 seconds. The BSS 32 determines the BCAST_INDEX parameter between 1 and 7 as specified by IS-95B to set the duration of the periodic broadcast paging cycle. In case of a conflict of broadcasting more than one message in a given time, the BSS 32 determines the order of broadcasting the messages according to a predetermined criterion.

The BSS 32 manages end-to-end delivery of messages and provides synchronization and scheduling services based on the interface primitives used in the CBC-BSC interface. IS-95B includes several different paging methods, which are applicable in the corresponding preferred embodiments of the present invention, and are described further below. Preferably, the BSC 34 can send broadcast pages and messages (as described below) to identify the cells so that the cell broadcast messages can be distributed to the identified geographical areas.

The MS 40 exchanges signals with the CDMA BSS 32 through the CDMA Um interface, and the MS and BSS protocol stacks have been modified to accommodate GSM network services such as the SMSCB described herein. The SMSCB message is sent from the BTS 36 to the MS 40 over the paging channel of the CDMA air interface.

FIG. 3 is a block diagram illustrating an SMSCB message 80 sent to the MS 40 over a paging channel according to a preferred embodiment of the present invention. Message 80 is a standard IS-95 data burst message (DBM)
With the form of. Message 80 encapsulates the entire GSM cell broadcast message, including GSM SMSCB header 86 and data 88, preferably according to GSM standard 03.41. The message 80 also includes a MSG LEN field 82, a CRC field 92 set by the BSS 32 to specify the total length of the message, both according to the IS-95 specification, and also a DBM header 84 and a 5 bit reserved field 90. Contains.

The DMB header 84 is set by the BSS 32 as generally in accordance with the IS-95B specification for paging channel messages, with the exception of the broadcast address field in the DBM header, the content of which is GSM standard 03.
． 41, section 9.3, "Message Formats at the BTS-MS Interface", are preferably configured for GSM cell broadcast services. The broadcast address field contains a portion of the cell broadcast message header generated by CBC 28, which uniquely identifies the message so that MS 40 detects a message that has already been received or is not of subscriber interest. Decoding can be avoided (the CBC message header contains the first 6 octets in a 88 octet complete message). B in the DBM header 84
MS40 ignores messages whose URST_TYPE and broadcast address fields are the same as those of earlier messages already received in a given periodic broadcast slot cycle.

[0045]   The structure of the Broadcast Address field is shown in Table I below.

[Table 1]

The structure of the serial number subfield is also defined according to the previously mentioned section of GSM standard 03.41, which is shown in Table II below.

[Table 2]

Message codes are assigned by the PLMN operator and can be used to identify different message themes.

Since it is not necessary to broadcast a given message by all cells within a given geographical area, as described in section 9.3 of the GSM03.41 standard mentioned above, The geographic range may be used to determine if two messages received in different cells and having the same serial number and message identifier are really the same.

Generally, as specified by IS-95B, MS 40 operates in slotted mode and is not constantly monitoring the paging channel. Therefore, when transmitting a cell broadcast message, it is preferable to use a specific procedure to ensure that the MS operating in slotted mode can receive the message.

Therefore, in a preferred embodiment of the present invention, the BSS 32 sends a broadcast page message, which may be, for example, a general page message specified by IS-95B, or a paging request message according to the GSM standard, or other. An appropriate message type that signals an upcoming broadcast message. The page record contained in the page message (which typically identifies the identifier of the MS to which the message is addressed) preferably contains the broadcast address, and the MS receiving the page message. Shows when a cell broadcast message should be sent. The actual cell broadcast message is then sent once. MS
One of them decodes the broadcast address in the page record,
One of the MSs can determine whether the broadcast message is a duplicate of a message that has already been received or is not of subscriber interest, and if so, the broadcast message. Avoid decoding itself.

In another preferred embodiment, the BSS 32 uses periodic broadcast paging cycles according to the IS-95B specification to reduce the overhead required to send broadcast messages. In this operating mode,
Since the MS 40 monitors the paging channel during the predetermined slot in which the broadcast page or message is being sent, the page and message need only be sent once during each periodic paging cycle. The broadcast page is preferably sent in the first slot of a given cycle, which is monitored by the MS and the broadcast message itself is IS-95.
It will be sent later according to B.

Broadcast message scheduling, as generally described in GSM 03.41, is used to distribute cell broadcast messages to MSs operating in slotted mode. In this case, the broadcast page message includes a schedule message in which the message type field (listed in Table I) is set to '1'. The schedule message immediately follows contains information about the number of consecutive cell broadcast messages transmitted during the schedule period consisting of one or more periodic broadcast cycles. The schedule message includes a message description for each message, along with the number of cycles that indicates its time position during the schedule period. The message description includes information from the broadcast address so that the MS can ascertain the type and source of each scheduled message, and whether the message has already been received.

Each schedule message includes fields that define the number of start cycles and the number of end cycles, which indicates the length of the schedule period. The new schedule message is preferably sent following the last message of the schedule period, ie in the cycle given by the preceding number of end cycles + 1. Several schedule messages can be sent for the same schedule period, with the starting cycle number indicating the first cycle immediately following the last schedule message.

When necessary, the BSS command is received to invalidate the schedule published in the schedule message, eg send a new high priority SMSCB message. Thereafter, the previous schedule of cell broadcast messages is resumed.

The methods and protocols described above apply when the MS 40 is in communication with a CDMA BSS 32. MS40 CBC28 through GSM BSS30
When communicating with, the communication protocol between these components follows the GSM standard without substantial modification.

Although the preferred embodiment has been described above with reference to specific TDMA and CDMA based communication standards, those skilled in the art may use the methods and principles described above with other methods of data encoding and signal modulation. You will understand that The scope of the present invention includes not only the complete systems and communication processes described above, but also various innovative components of these systems and processes, as well as combinations and some combinations thereof. In particular, although the preferred embodiment has been described above with reference to a hybrid TDMA / CDMA system 20 and MS 40, it should be understood that the described method and apparatus could equally be used to convey a cell broadcast message to an MS in a CDMA system without TDMA capabilities. You can understand.

Therefore, it should be understood that the preferred embodiments described above are cited by way of illustration, and the full scope of the invention is limited only by the claims.

[Brief description of drawings]

FIG. 1 is a hybrid GSM / CDM according to a preferred embodiment of the present invention.
It is a schematic block diagram of an A cellular communication system.

FIG. 2 is a schematic block diagram illustrating a communication protocol between components of the system of FIG. 1 according to a preferred embodiment of the present invention.

FIG. 3 is a schematic block diagram illustrating a message format for use in a cell broadcast service message according to a preferred embodiment of the present invention.

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE), OA (BF, BJ , CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, K E, LS, MW, MZ, SD, SL, SZ, TZ, UG , ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, BZ, C A, CH, CN, CR, CU, CZ, DE, DK, DM , DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, K E, KG, KP, KR, KZ, LC, LK, LR, LS , LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, PL, PT, RO, R U, SD, SE, SG, SI, SK, SL, TJ, TM , TR, TT, TZ, UA, UG, UZ, VN, YU, ZA, ZW (72) Inventor Coller, Sergio             34612 Haifa, Nashi, Israel             Yon 4/1 (72) Inventor Nizuri, Shuromo             The State of Israel 17905 Kibbutz Haseleri             Mu (no address) (72) Inventor Levy, Atay             Israel 34612 Haifa, I             Street 7 F term (reference) 5K067 BB03 BB04 CC10 DD51 EE04                       EE10 GG01 GG11

Claims (26)

[Claims] 1. A method of broadcasting a message through a CDMA air interface in a GSM mobile wireless communication system, the method comprising: delivering a message to a base station and transmitting a message to a mobile station through a CDMA air interface, substantially according to a GSM cell broadcast service protocol. A method comprising sending. 2. The method of claim 1, wherein transmitting the message transmits the message substantially in accordance with a CDMA transmission standard. 3. The method of claim 2, wherein the CDMA transmission standard includes IS-95B. 4. Sending a message is a G-message in an IS-95 message.
The method of claim 2 including encapsulating the SM cell broadcast message. 5. The method of claim 1, wherein sending the message comprises sending the message over a paging channel. 6. The method of claim 5, wherein sending the message includes directing the message to one or more specific cells. 7. The method of claim 5, wherein sending the message comprises sending the message such that it is more likely to be received by the mobile station while the mobile station is operating in slotted mode. 8. The method of claim 7, wherein sending the message includes sending a broadcast page followed by sending the message. 9. The method of claim 8, wherein transmitting the broadcast page comprises transmitting the page in a predetermined slot monitored by the mobile station in periodic paging cycles. 10. Sending a schedule message that includes information about one or more broadcast pagings to be sent during a schedule period that constitutes one or more periodic broadcast paging cycles.
The method described. 11. The method of claim 1, wherein sending a message comprises sending a single message multiple times substantially in accordance with a GSM cell broadcast command. 12. Sending a single message comprises assigning a broadcast address to the message, whereby the mobile station receives a second message having the same broadcast address as the earlier message, the first message. The method of claim 1, wherein the second message is discarded when said. 13. The method of claim 11, wherein transmitting a single message multiple times comprises repeating transmission of the message at a repetition frequency determined in response to a cell broadcast command. 14. The method of claim 1, wherein delivering the message comprises receiving the message from a cell broadcast center. 15. Sending a message includes sending a message header including a message identifier field indicating a characteristic of the message, the mobile station responsive to the characteristic determining whether to decode or discard the message. The method of claim 1, wherein 16. An apparatus for broadcasting a short message from a cell broadcast center over a CDMA air interface, the message being received from the cell broadcast center substantially according to the GSM Cell Broadcast Service Protocol and transmitting the message through the CDMA air interface. An apparatus comprising a base station subsystem that operates. 17. The apparatus of claim 16, wherein the base station subsystem transmits the message substantially according to the CDMA transmission standard. 18. The apparatus of claim 17, wherein the CDMA transmission standard includes IS-95B. 19. The apparatus of claim 17, wherein the base station encapsulates the GSM cell broadcast message in an IS-95 message. 20. The apparatus of claim 16, wherein the base station subsystem sends the message over a paging channel. 21. The apparatus of claim 16, wherein the base station subsystem directs messages to one or more particular cells. 22. The apparatus of claim 16, wherein the base station subsystem transmits the message such that the mobile station is likely to be received by the mobile station while operating in slot mode. 23. The apparatus of claim 22, prior to transmitting the message, the base station subsystem transmits the page in a predetermined slot monitored by the mobile station in periodic paging cycles. 24. The apparatus of claim 16, wherein the base station subsystem comprises sending the single message multiple times substantially in accordance with the GSM cell broadcast command. 25. The apparatus of claim 24, wherein the base station subsystem repeats transmitting the message at a repetition frequency determined in response to the cell broadcast command. 26. The base station subsystem assigns a broadcast address to the message such that when the mobile station receives a second message having the same broadcast address as the earlier message, the second message. 25. The apparatus of claim 24, wherein the message is discarded.