HK1104743A

HK1104743A - Short message conversion between different formats for wireless communication systems

Info

Publication number: HK1104743A
Application number: HK07111983.9A
Authority: HK
Inventors: N．尤齐达; H．瞿
Original assignee: 高通股份有限公司
Priority date: 2002-07-09
Filing date: 2006-01-10
Publication date: 2008-01-18

Description

Short message conversion between different formats in a wireless communication system

The application is a divisional application of the Chinese patent application with the application number of 03820148.8, which is named as 'short message conversion between different formats of wireless communication system' on the 7 th and 9 th 2003.

Background

Technical Field

The present invention relates generally to wireless messaging communications, and more particularly to techniques for converting short messages between different formats used by different wireless communication systems (e.g., GSM and CDMA).

Background

Short Message Service (SMS) is a service that supports the exchange of SMS or short messages between a mobile station and a wireless communication system. These short messages may be user-specific messages directed to a particular recipient mobile station, or broadcast messages directed to multiple mobile stations.

SMS can be implemented in various types of wireless communication systems, two of which are Code Division Multiple Access (CDMA) systems and Time Division Multiple Access (TDMA) systems. A CDMA network may be designed to implement one or more standards such as CDMA2000, W-CDMA, IS-95, and so on. TDMA networks may also be designed to implement one or more standards such as global system for mobile communications (GSM). Each network typically also implements a specific mobile networking protocol that allows roaming and advanced services, with ANSI-41 typically used for CDMA networks (except W-CDMA) and GSM mobile application part (GSM-MAP) typically used for GSM and W-CDMA networks.

Since SMS is network technology (ANSI-41 or MAP) dependent, CDMA and GSM networks implementing different network technologies support different implementations of SMS. Each SMS implementation has different capabilities and uses different message types and formats to send short messages. Each SMS implementation allows different handling of short messages. For example, for an SMS implementation in GSM-MAP, the user data within the short message may be sent in compressed or uncompressed form, with the compression algorithm defined by a standard. For simplicity, an SMS implementation within a GSM-MAP based network is referred to as GSM SMS, and an SMS implementation within an ANSI-41 based network is referred to as CDMA SMS.

Although CDMA and GSM differ in design, Interworking and Interoperability Functions (IIFs) have been defined to allow communication between these two different network types. The result is that improved coverage and performance may be reserved for mobile users or subscribers of the network. In particular, with IIF, a GSM mobile user may roam into the coverage area of a CDMA network and be able to continue receiving service, and vice versa.

If both CDMA and GSM networks support SMS, one of the functions of the IIF is to convert each short message originating from one network into the appropriate format required by the other network before forwarding it to the other network. However, since CDMA and GSM networks with different network technologies support different kinds of SMS implementations, CDMA SMS and GSM SMS may not be able to convert short messages of one system into a specific format required by another system under current standards. For example, since GSM SMS supports compressed and uncompressed user data, and CDMA SMS does not support compressed formats, the IIF may need to decompress the user data within the encapsulated GSM SMS message and convert it to a CDMA SMS message. In addition, the GSM SMS message may contain other fields that are not present within the CDMA SMS message.

There is therefore a need in the art for techniques to convert GSM SMS messages to CDMA SMS messages and vice versa, thereby solving the above-mentioned problems.

Disclosure of Invention

Techniques are provided for converting short messages between different formats used by different wireless communication systems (e.g., GSM SMS and CDMA SMS) so that the relevant control information can be retained without changing the basic structure of the formats. In one aspect, improved support for GSM SMS in a CDMA network is achieved by defining a new value for a first designated field in a CDMA SMS message to indicate that the CDMA SMS message is an encapsulated GSM SMS message. A second specified field within the CDMA SMS message may be used to convey data coding scheme information for the encapsulated GSM SMS message. The first and second designated fields may be the Msg _ Encoding field and the Message _ Type field, respectively, within the user data subparameter of the CDMA SMS Message.

In one embodiment, a method is provided for converting a first short message (e.g., a GSM SMS message) in a first format to a second short message (e.g., a CDMA SMS message) in a second format. According to the method, a first field (e.g., Msg _ Encoding field) in the second message is set to a value representing a short message in the first format included in the second message. A second field (e.g., the Message Type field) within the second Message is set to a value that indicates the data coding scheme used by the first Message (e.g., indicated within the TP data coding scheme field within the GSM SMS Message). A data field (e.g., CHARi field) in the second message is set to the data included in the first message. The length field in the second message (e.g., the Num _ Fields field in the user data subparameter) can also be set to a value that indicates the length of the data included in the first message (e.g., as indicated by the TP user data length field in the GSM SMS message).

In another embodiment, a method of processing a received short message is provided. According to the method, a value in a first field in the received short message (e.g., the Msg _ Encoding field in a CDMA SMS message) is obtained and used to determine whether the received short message comprises an encapsulated message (e.g., a GSM SMS message). If the received short Message comprises an encapsulated Message, a value representing the data encoding scheme used to compress the Message is obtained from a second field (e.g., a Message Type field) within the received short Message, and the data within the received short Message is then processed based on the data encoding scheme. If the data encoding scheme indicates that the data has been compressed, the processing may include decompressing the data within the received short message. Alternatively, if the received short message does not include an encapsulated message, data within the received short message may be processed based on the value obtained from the first field.

Various aspects and embodiments of the invention are described in further detail below. The invention also provides methods, program codes, digital signal processors, mobile stations, base stations, systems, and other apparatuses and elements that implement various aspects, embodiments, and features of the invention, as described in detail below.

Drawings

The features, nature, and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like elements have like numerals wherein:

FIG. 1 is a schematic diagram of a communication network including a CDMA network and a GSM network;

FIGS. 2A and 2B are schematic diagrams illustrating a GSM SMS message format and a CDMA SMS message format, respectively;

FIG. 3 is a diagram illustrating the conversion from a GSM SMS message to a CDMA SMS message;

FIG. 4 is a signal flow diagram illustrating a process for sending an SMS message from a GSM network to recipient mobile stations within a CDMA network;

fig. 5 is a flow chart of a process performed for a short message received by a mobile station in a CDMA network; and

fig. 6 is a block diagram of an embodiment of a message/service center and a mobile station.

Detailed Description

Fig. 1 is a schematic diagram of a communication network 100 including a CDMA network 110 and a GSM network 120. An Interworking and Interoperability Function (IIF) supports communications between CDMA and GSM networks.

CDMA networks can be designed to conform to ANSI-41 entitled "Cellular radio communications inter system Operations," which is a mobile networking protocol that allows roaming and advanced services. Roaming refers to the use of a mobile station when leaving a home area. The CDMA network includes a number of entities that collectively support communication for mobile station 140 within the network. For simplicity, fig. 1 only shows CDMA network entities supporting Short Message Service (SMS). In particular, the Message Center (MC)112 is responsible for storing, relaying, and forwarding short messages for mobile stations, while the Mobile Switching Center (MSC)114 performs switching functions (i.e., routing of messages and data) for mobile stations within their coverage area. The message center may be separate from the MSC or integrated with them. Each mobile station is served by an MSC at any given moment, which is referred to as the mobile station's serving MSC. A mobile station may also be called a remote station, a terminal, a user equipment (IE), or some other terminology.

GSM networks may be designed to comply with GSM mobile application part (GSM-MAP), which is another mobile networking protocol that allows roaming and advanced services. The GSM network comprises a plurality of entities that together support the communication of mobile stations within the network, of which only functional GSM network entities for SMS are shown in fig. 1. The GSM SMS service center (GSM-SMS-SC)122 is responsible for saving, relaying and forwarding short messages for mobile stations. GSM MSC124 performs switching functions for mobile stations within their coverage area. The GSM SMS gateway MSC (GSM-SMS-GMSC)126 is an MSC function capable of receiving short messages from the GSM-SMS-SC, inquiring the Home Location Register (HLR) for routing information and SMS information for each short message, and delivering the short messages to the appropriate serving node (or base station) for the mobile stations that are the target recipients of these messages. The GSM SMS networking MSC (GSM-SMS-IWMSC)128 is an MSC function that can receive short messages and submit them to the GSM-SMS-SC.

For W-CDMA, the lower layers are based on CDMA technology, the higher layers are similar to the higher layer protocols of GSM, and the core network is based on GSM-MAP. As used herein, "CDMA" refers to a CDMA-based system or network that implements ANSI-41.

The interface Q between entities in a CDMA network and the interface E between entities in a GSM network are defined by ANSI-41 and GSM-MAP, respectively.

To support mobile networking in accordance with ANSI-41 and GSM-MAP, each network maintains a Home Location Register (HLR) and a Visitor Location Register (VLR). The HLR and VLR are databases used to store information about mobile stations within the network. For example, as mobile stations move between networks, their locations are continually updated in these databases so that the networks can learn where they are at any time. The network can then query (or interrogate) these databases to obtain routing information for the short message.

As described above, CDMA and GSM networks support different implementations of SMS. Each SMS implementation provides different capabilities and uses different short message types and formats.

Fig. 2A is a diagram illustrating a GSM SMS short message. At the short message transport layer (SM-TL), which is one of the layers of the SMs protocol stack within GSM, six different Protocol Data Units (PDUs) are defined for SMs messages. Among these data units, the SMS-DELIVER PDU is used to transmit a short message from the service center to the mobile station, and the SMS-SUBMIT PDU is used to transmit a short message from the mobile station to the service center. Other PDUs are used to convey status, reports, commands and acknowledgements.

The SMS-DELIVER and SMS-SUBMIT PDUs have the general format shown in FIG. 2A. Each of these two PDUs includes a plurality of fields, but only three fields of interest in this description are shown in fig. 2A. Table 1 lists these three fields and their short descriptions, where TP denotes the transport protocol.

TABLE 1

Abbreviations	Full scale	Length of	Description of the invention
Abbreviations	Full scale	Length of	Description of the invention	TP-DCS	TP data coding scheme	8 bit	Identifying parameters of a data coding scheme within TP user data
TP-UDL	TP user data Length	8 bit	Parameter indicating length of TP user data	TP-DCS	TP data coding scheme	8 bit
TP-UDL	TP user data Length	8 bit	Parameter indicating length of TP user data	TP-UD	TP user data	Variable	User data of short message

The TP user data field contains user data of the short message. The user data is typically a character message generated based on a particular character set or encoding scheme. However, if a user data header is included in the TP user data field, the content of the message may also be in multimedia or other enhanced format in addition to the character content. The length of the TP-user-data field is defined by the value in the TP-user-data length field and is given in units corresponding to the length of each character of the selected character set, which may be 7, 8 or 16 bits. The TP data coding scheme field describes various attributes of the data within the TP user data field, as described below.

Table 2 lists elements of the TP data coding scheme field

TABLE 2

Bit	Description of the invention
Bit	Description of the invention	7-6	The general data encoding representation is set to "00".
5	The uncompressed data in the TP user data field is set to "0". The compression data is set to "1".	7-6	The general data encoding representation is set to "00".
5		4	Bits 1-0 are set to "0" if they have no meaning. Bits 1-0 are set to "1" if they are used to indicate a message class.
3-2	The character set "00" used for data in the TP user data field is GSM 7 bits, and the default alphabet "01" is 8 bits of data "10" is UCS2(16 bits) "11" is reserved.	4
3-2		1-0	Indicating the message class (if enabled by bit 4)

"00" for class 0 "01" for class 1, default meaning: ME-specific "10" ═ class 2, (U) SIM-specific message "11" ═ class 3, default meaning: special for TE

The TP data coding scheme field is 8 bits in length. Bits 6 and 7 are set to "00" for the general data encoding indication and to some other value for the other indications. Bit 5 is used to indicate whether the data in the TP user data field is uncompressed or compressed using a dedicated compression scheme. Bit 4 is used to "enable" bits 1-0. Bits 2 and 3 are used to indicate the character set or encoding scheme used for the data, and the default character set is GSM 7 bits. Bits 0 and 1 are used to indicate the message class of the short message.

GSM SMS message formats are further detailed in documents 3GPP TS23.038 V5.0.0 and TS 23.040 V4.7.0, both of which are published and incorporated herein by reference.

Fig. 2B is a diagram illustrating a CDMA SMS message format. At the SMS teleservice layer, which is one of the layers of the SMS protocol stack in CDMA, an SMS transport message is used to send short messages to the mobile station and an SMS submit message is used to send short messages from the mobile station. These messages have the general format shown in fig. 2B, which includes a number of subparameters. Table 3 lists two sub-parameters of these messages and their short descriptions.

TABLE 3

Sub-parameters	Length of	Description of the invention
Sub-parameters	Length of	Description of the invention	Message identifier	5 bytes	Including the message type and message identification used for the acknowledgement.
User data	Variable	Including the various attributes of the user data within the short message and the user data itself.	Message identifier	5 bytes

Table 4 lists the fields of the user data subparameter.

TABLE 4

Field(s)	Length of	Description of the invention
Field(s)	Length of	Description of the invention	Subparameter_ID	8 bit	For user data the sub-parameter is set to "00000001"
Subparam_Len	8 bit	Indicates the length of the user data Subparameter, excluding the Subparameter _ ID and Subparam _ Len fields.	Subparameter_ID	8 bit	For user data the sub-parameter is set to "00000001"
Subparam_Len	8 bit		Msg_Encoding	5 position	Indicating the coding scheme used for the user data within the short message.
Message_Type	0 or 8 bit	Indicating the message type of the short message.	Msg_Encoding	5 position
Message_Type	0 or 8 bit	Indicating the message type of the short message.	Num_Fields	8 bit	The number of occurrences of the chari field is indicated and generally corresponds to the number of characters in the user data.

Num _ Fields of the following Fields occur:

chari

variable

Containing one character of user data within either a CDMA SMS short message or encapsulated GSM SMS TP user data.

The user data subparameter ends with the following fields:

padding (filling)

0 to 7 positions

Including a sufficient number of bits to make the user data subparameter an integer number of octets in length.

As shown in table 4, the user data of the CDMA SMS message is contained in the CHARi field, which occurs once for each character, the total number of occurrences being represented by the value in the Num _ fields field. The Msg _ Encoding field indicates the particular Encoding scheme used for the characters in the CHARi field. Since different coding schemes may have different character lengths, the length of the CHARi field is determined by the coding scheme used for the user data in the short message.

The CDMA SMS message format is further detailed in TIA/EIA-637-B, entitled "short message Service for Wireless band Spread Spectrum Systems". The parameter Value assignment for the Msg _ Encoding field is further detailed in TSB-58-E, entitled "Addition of parameter Value Assignments for cdma2000 Spread Spectrum Standards". Both of these documents are published and incorporated herein by reference.

GSM SMS messages need to be converted into CDMA SMS messages in various situations. For example, message conversion may be required when a GSM mobile user roams into a CDMA network and receives a short message in the CDMA network, or when a CDMA mobile user within a CDMA network receives a short message from a GSM mobile user. The Interworking and Interoperability Function (IIF) would then perform the conversion from GSM SMS messages to CDMA SMS messages.

From the above description, it can be seen that a "basic" uncompressed GSM SMS message can be converted into a CDMA SMS message by simply mapping fields within the GSM SMS message to corresponding fields within the CDMA SMS message. In particular, GSM to CDMA message conversion may be achieved by: (1) map the data in the TP user data field in the GSM SMS message to the CHARi field in the user data subparameter of the CDMA SMS message, and (2) set the Msg _ Encoding field in the user data subparameter to "01001" for the GSM 7-bit default alphabet.

However, if the GSM SMS message has been compressed using the compression algorithm defined in 3GPP TS 23.042 V4.0.1, the IIF would need to decompress the user data to obtain uncompressed data, which is then included in the CHARi field of the CDMA SMS message. This may be necessary because there is currently no field in the CDMA SMS message format that can indicate to the recipient mobile station whether the user data is compressed or uncompressed. In addition, as shown in table 2 and fig. 2A, the GSM SMS message format includes a message class and some other indication in the TP data coding scheme field. There are currently no corresponding fields for these elements within the CDMA SMS message format, which also need to be mapped in order to more fully support GSM SMS within a CDMA network.

In one aspect, improved support for GSM SMS in a CDMA network is achieved by defining a new value for the Msg _ Encoding field in the user data subparameter to indicate that the contents of the CDMA SMS message are an encapsulated GSM SMS message. The Msg _ Encoding field includes 5 bits for 32 possible values, 10 of which are currently defined by TSB-58-E for ten different coding schemes, and is assigned values of "00000" to "01001" for the Msg _ Encoding field. Any one of the reserved values "01010" through "11111" may then be used to identify the new coding scheme for the GSM SMS message. This new coding scheme can be denoted as "GSM SMS data coding". As a specific example, the value "01010" may be used for "GSM SMS data Encoding", in which case the Encoding scheme defined for use in the Msg _ Encoding field of the user data subparameter may be updated from the current TIA/EIA-637B standard, as shown in Table 5.

TABLE 5

chari coding type	Msg _ Encoding field	Length of
chari coding type	Msg _ Encoding field	Length of	Λ	Λ	Λ
GSM SMS data coding (New)	“01010”	Note 2	Λ	Λ	Λ
GSM SMS data coding (New)	“01010”	Note 2	All other values are reserved

Note that 2: the length of each CHARi field is determined by the character set indicated in the TP data coding scheme field, which is included in the Message _ Type field of the CDMA SMS Message.

Fig. 3 is a diagram illustrating one embodiment of the conversion of a GSM SMS message to a CDMA SMS message, enabling the retention of relevant control information. The GSM to CDMA message conversion may be performed as follows:

1) setting the Msg _ Encoding field in the user data subparameter of the CDMA SMS message to the value assigned to "gsm SMS user data Encoding" (e.g., assigned "01010" for the example parameter value);

2) setting a Message _ Type field in the user data subparameter to a value in a TP data coding scheme (TP-DCS) of the GSM SMS Message;

3) setting Num _ Fields in the user data subparameter to a value in a TP user data length (TP-UDL) field; and

4) the CHARi field in the user data subparameter is set to the data in the TP user data (TP-UD) field.

CDMA SMS messages can also be sent to mobile subscribers within a GSM network using features supported by GSM SMS. To accomplish this, the CDMA network can originate a CDMA SMS message that includes a GSM SMS message encapsulated as described above. The IIF would then perform an inverse CDMA to GSM message conversion to convert the CDMA SMS message to a GSM SMS message, as follows:

1) setting a TP-data coding scheme (TP-DCS) field of the GSM SMS Message to a value in a Message _ Type field within a user data subparameter of the CDMA SMS Message;

2) setting a TP user data length (TP-UDL) field to a value in a Num _ Fields field in a user data subparameter; and

3) the TP user data (TP-UD) field is set to the data in the CHARi field in the user data subparameter.

Fig. 3 illustrates a particular message conversion scheme for mapping GSM SMS messages to CDMA SMS messages so that the relevant control information can be retained without changing the CDMA SMS message format. Other arrangements may also be implemented based on the principles described herein and are intended to be within the scope of the present invention. In one example, a currently unused value of the Message _ Type field (e.g., "0111") within the Message identifier subparameter may be used to indicate "GSM SMS data encoding". Other fields within other subparameters of the CDMA SMS message may also be used to represent the "GSM SMS data encoding" and to convey the TP-DCS field, which is within the scope of the present invention.

The above message conversion can map the SMS data coding scheme defined by GSM/UMTS to a CDMA SMS message without changing the basic structure of the CDMA SMS message format. By using these message conversion schemes, the IIF can map user data within a GSM SMS message directly to a CDMA SMS message even if the compression and/or some other indication used by the user data is included within the GSM SMS message. These message conversion schemes are preferably used in a variety of situations, including: (1) a GSM mobile subscriber roams to a CDMA network and receives an SMS message originating from a GSM network, (2) a GSM mobile subscriber sends an SMS message to a CDMA mobile subscriber, (3) a CDMA mobile subscriber roams to a GSM network and receives an SMS message originating from a CDMA network, (4) a CDMA mobile subscriber sends an SMS message to a GSM mobile subscriber, and (5) a GSM mobile subscriber within a GSM1x network receives a GSM SMS message via a CDMA air interface. In the GSM1x network, the GSM-MAP network is overlaid on a CDMA air interface, and GSM SMS messages are sent in CDMA SMS messages over the CDMA air interface.

Fig. 4 is a diagram illustrating the signal flow for sending an SMS message from a GSM network to a recipient mobile user in a CDMA network. The SMS message may be sent by a GSM mobile subscriber or by a CDMA mobile subscriber who has roamed into a GSM network. The message recipient may be a CDMA mobile subscriber or a GSM mobile subscriber that has roamed into a CDMA network.

First, the GSM SMS service center (SMS-SC) receives an SMS message for a particular mobile subscriber, called the recipient mobile subscriber (transaction) a. The SMS-SC then communicates with the GSM SMS-GMSC to originate a short message routing information to the GSM HLR of the recipient mobile subscriber to request the routing address of the mobile subscriber (transaction b). The routing address is used to deliver the short message to the recipient mobile user. If the recipient mobile subscriber has a current and valid location stored in the GSM HLR, the HLR returns the short message result message to the SMS-GMSC via its send routing information (transaction c). The SMS-GMSC then sends a forward short message (transaction d) to the IIF.

In general, the IIF provides an interface from the CDMA SMS (ANSI-41) Message Center (MC) and the GSM SMS service center (SMS-SC) to the serving MSC using an external network signaling protocol (i.e., outside of the message center and service center). The functionality provided by the IIF is described in detail in J-STD-038-A, entitled "network interworking Between GSM Map and TIA/EIA-41-Map-discovery A-GPRS Support", which is published and incorporated herein by reference.

For this SMS message, the IIF is seen by the GSM network entity as the serving GSM MSC/VLR. Upon receiving the forward short message from the SMS-GMSC, the IIF converts the SMS message using the GSM to CDMA message conversion scheme described above. The result of the conversion is a CDMA SMS message format appropriate and including an encapsulated message. At this point, the IIF would then act as the ANSI-41 message center. The IIF then initiates a short messaging point-to-point message to send the converted CDMA SMS message to the serving CDMA MSC and VLR (transaction e).

The serving CDMA MSC/VLR receives the message from the IIF and sends a CDMA SMS message to the recipient mobile station (transaction f). For certain types of SMS messages, the serving CDMA MSC/VLR may receive an acknowledgement from the recipient mobile station, which may be part of transaction f. In this case, the serving CDMA MSC/VLR then sends the result of the short messaging point-to-point message back to the IIF (transaction g). The IIF then sends the result of the forward short message to the GSM SMS-GMSC.

Fig. 5 is a flow diagram of one embodiment of a process 500 performed for a short message received by a mobile station in a CDMA network. The process assumes that the short message is converted as needed using the GSM to CDMA message conversion scheme described above.

First, the user data subparameter of the received short message is obtained (step 512). The value in the Msg _ Encoding field of the user data subparameter is then obtained (step 514). It is then determined whether the Msg _ Encoding value is equal to the value assigned to "GSM SMS data Encoding" (step 516). If the answer is no, the received message is either a CDMA SMS message or a message that does not require processing of an encapsulated GSM SMS message. In this case, the user data in the CHARi field of the user data subparameter is processed in a conventional manner based on the Msg _ Encoding value (step 522).

However, if the Msg _ Encoding value is equal to the "GSM SMS data Encoding" value, as determined in step 516, then the received short message comprises an encapsulated GSM SMS message. In this case, the TP data encoding scheme of the SMS Message is obtained from the Message _ Type field in the user data subparameter (step 518). The user data in the CHARi field of the user data subparameter contains TP user data for the short message, which is then processed based on the TP data coding scheme (step 520). As part of this process, user data may be decompressed if the TP data encoding scheme indicates that the data has been compressed prior to transmission. The processing of user data in short messages may be performed as described in 3GPP TS23.038 V5.0.0. After steps 520 and 522, the process terminates.

Fig. 6 is a block diagram of an embodiment of a message/service center 600 and a mobile station 140 x. The message/service center 600 provides Interworking and Interoperability Functions (IIF) for SMS and may be implemented within an ANSI-41 message center or a GSM SMS service center.

Center 600 receives SMS messages originating from GSM MSC124 and/or CDMA MSC 114 for transmission from external networks. The received short message is temporarily stored in the message buffer 612. These short messages are then retrieved from the buffer and provided to short message converter 614 for conversion to the appropriate format as needed. In particular, short message converter 614 performs GSM to CDMA message conversion such that GSM SMS messages are sent from the CDMA network, and CDMA to GSM message conversion such that CDMA SMS messages are sent from the GSM network. Message conversion may be performed as described above.

The converted short message is then provided to the CDMA MSC 114 and/or GSM MSC124 serving the external network. The serving MSC then forwards the converted short message to a serving node (or base station) 130 that currently serves the mobile station as the recipient of the message. Each serving node processes the received short messages and includes them in a modulated signal to be transmitted to mobile stations within its coverage area.

Within the center 600, a controller 620 directs the flow of short messages through the center and further controls the conversion of short messages as appropriate. This may be accomplished by determining the source and recipient of each short message received by the center 600. A memory unit 622 provides storage for program codes and data used by controller 620.

Fig. 6 also shows one embodiment of a mobile station 140 x. The modulated signal transmitted from the serving node for the mobile station is received by an antenna 652 and provided to a receiver unit (RCVR) 654. Receiver unit 654 conditions (e.g., filters, amplifies, and frequency downconverts) the received signal and further digitizes the conditioned signal to provide samples.

A demodulator (Demod)/decoder 656 then demodulates the samples in a particular manner determined by the particular network (CDMA or GSM) from which the modulated signal was received. The modulated data is then decoded to provide decoded data, which includes the short message transmitted within the modulated signal. Short message processor 658 then processes the received short messages (e.g., as described above in fig. 5) to provide the user data included in the short messages. For example, if the TP data coding scheme indicates that compressed data is included in the short message, short message processor 658 may perform message conversion and possibly decompress the user data within the CHARi field of the user data subparameter.

Controller 660 directs the operation of the units within mobile station 140 x. For example, the controller 660 may instruct the short message processor 658 to use a particular coding scheme, perform decompression, etc. for each received short message destined for the mobile station to provide the correct user data. A memory unit 662 provides storage for program codes and data used by controller 660.

Fig. 6 illustrates a particular embodiment of a center 600 and a mobile station 140 x. Other embodiments are possible and are within the scope of the invention. For the hub 600, the short message converter 614 may also be implemented in the controller 620 or in some other processing unit, such as a message formatter. Similarly, for mobile station 140x, short message processor 658 may be implemented within controller 660 or some other processing element (e.g., demodulator/decoder 656).

The above-described short message conversion and processing techniques may be implemented by various means. For example, these techniques may be implemented in hardware, software, or a combination thereof. For a hardware implementation, the elements used to implement any one or a combination of the techniques described herein (e.g., message conversion at center 600, message processing at mobile station 140, etc.) may be implemented within: one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof.

For a software implementation, the short message conversion and processing techniques may be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in a memory unit (e.g., memory units 622 and 662 in fig. 6) and executed by a processor (e.g., controllers 620 and 660). The memory unit may be implemented within the processor or external to the processor, in which case it can be communicatively coupled to the processor via various means as is known in the art.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for converting a first short message in a first format to a second short message in a second format, comprising:

setting a first field in the second short message to a value representing a short message of the first format included in the second short message;

setting a second field within said second short message to a value indicative of the data encoding scheme used by said first short message;

setting a data field in the second short message as data in a data field included in the first message;

setting a length field within said second short message to a value representing the length of data included within said first short message; and

defining a new value for said first field within said second short message, wherein said new value represents a data coding scheme used by an encapsulated message of said first format,

wherein the first short Message is a GSM SMS Message, the second short Message is a CDMA SMS Message, the first field of the second short Message is a Msg _ Encoding field, and the second field of the second short Message is a Message _ Type field.

2. A method for converting a first short message in a first format into a second short message in a second format as claimed in claim 1, characterized by:

the TP data coding scheme field in the first short message indicates the data coding scheme used by the first short message, the data field of the second short message is the CHARi field in the user data subparameter, the data field in the first short message is the TP user data field, the length field in the second short message is the Num _ Fields field in the user data subparameter, and the length of the data included in the first short message is indicated by the TP user data length field in the first short message.

3. The method for converting a first short message in a first format to a second short message in a second format as recited in claim 1, further comprising:

determining from the value representing the data encoding scheme in the first field of the second short message whether the received short message comprises an encapsulated message; and

processing the received short message according to the data coding scheme.

4. The method of claim 1, wherein said step of defining a new value for said first field within said second short message comprises:

setting the Msg _ Encoding field in the user data subparameter of the second short message to the value of "GSM SMS data Encoding", thereby indicating that the content of the second short message is an encapsulated first short message.

5. The method of claim 1, wherein said step of defining a new value for said first field within said second short message comprises:

setting the Msg _ Encoding field in the user data subparameter of the second short message to '01001' for the GSM 7-bit default alphabet of the first format, thereby indicating an encapsulated first short message.

6. The method of claim 3, wherein the step of processing comprises decompressing the data.

7. A method for converting a CDMA SMS message to a GSM SMS message, comprising:

setting a TP data coding scheme field of the GSM SMS message to a value within a specified field of the CDMA SMS message;

setting a TP user data field in the GSM SMS message to data in a CHARi field of the CDMA SMS message; and

the TP user data length field in the GSM SMS message is set to the value in the Num _ Fields field of the CDMA SMS message.

8. The method for converting a CDMA SMS Message to a GSM SMS Message of claim 7, wherein the specified field is a Message _ Type field within a user data subparameter of the CDMA SMS Message, and the CHARi field and the Num _ Fields field are both within the user data subparameter of the CDMA SMS Message.

9. A message service center for processing short messages, comprising:

at least one message buffer, whereby short message service messages are received and stored;

at least one short message converter operatively connected to the message buffer, thereby converting the format of the stored message;

at least one controller operatively connected to said message buffer and said short message converter, thereby directing a short message flow; and

at least one memory unit operatively connected to the controller, thereby storing program code.

10. The message service center for processing a short message as claimed in claim 9, wherein the short message originates from a GSM mobile switching center and a CDMA mobile switching center.

11. A message service center for processing short messages as claimed in claim 9, characterized in that the program code comprises software for converting a first short message in a first format into a second short message in a second format, comprising:

12. A message service center for processing short messages as claimed in claim 9, characterized in that the program code comprises software for converting a first short message in a first format into a second short message in a second format, comprising:

13. A message service center as claimed in claim 11, wherein:

14. The message service center of claim 11, wherein the software further comprises:

processing the received short message according to the data coding scheme.

15. The message service center of claim 11 wherein the software that defines a new value for the first field within the second short message comprises:

16. The message service center of claim 11 wherein the software that defines a new value for the first field within the second short message comprises:

17. The Message service center of claim 12 wherein the specified field is a Message _ Type field within a user data subparameter of the CDMA SMS Message, and wherein the CHARi field and the Num Fields are both within the user data subparameter of the CDMA SMS Message.

18. The message service center of claim 15 wherein the processing comprises decompressing the data.

19. A mobile station for processing a short message, comprising:

an antenna;

a receiver operatively connected to the antenna;

a demodulator/decoder operatively connected to the receiver;

a short message processor operatively connected to said demodulator/decoder, thereby to process the received short message;

at least one controller operatively connected to the short message processor;

20. The mobile station for processing short messages as claimed in claim 19, wherein said program code includes software for converting a first short message in a first format to a second short message in a second format, including:

21. The mobile station for processing short messages as claimed in claim 19, wherein said program code includes software for converting a first short message in a first format to a second short message in a second format, including:

22. The mobile station of claim 20, wherein:

23. The mobile station of claim 20, wherein the software further comprises:

processing the received short message according to the data coding scheme.

24. The mobile station of claim 20 wherein said software defining a new value for said first field in said second short message comprises:

25. The mobile station of claim 20 wherein said software defining a new value for said first field in said second short message comprises:

26. The mobile station of claim 21, wherein said specified field is a Message _ Type field within a user data subparameter of said CDMA SMS Message, and said CHARi field and said Num _ Fields field are both within a user data subparameter of said CDMA SMS Message.

27. The mobile station of claim 23, wherein said processing comprises decompressing said data.