GB2409385A

GB2409385A - Wireless messaging maintaining different bit-wise boundaries

Info

Publication number: GB2409385A
Application number: GB0329383A
Authority: GB
Inventors: Paul Barrie Douglas
Original assignee: Sendo International Ltd
Current assignee: Sendo International Ltd
Priority date: 2003-12-18
Filing date: 2003-12-18
Publication date: 2005-06-22
Anticipated expiration: 2023-12-18
Also published as: GB2409385B; GB0329383D0

Abstract

A method of encoding messages that require components within the message to maintain different bit-wise boundaries (300) comprising the steps of calculating (315) a header length for concatenating two or more messages, applying textual data from the two or more messages to fill a second part of the concatenated message; and subsequently overlaying (330) header data (442) to a first part of the concatenated message. May be used particularly for GSM SMS or EMS messages.

Description

MESSAGING IN A WIRELESS COMMUNICATION UNIT

Field of the Invention

This invention relates to a wireless communication unit and method of generating and receiving messages in a wireless communication unit such as a mobile phone. The invention is applicable to, but not limited to, the use of short message service (SMS) or enhanced message service (EMS) messages (such as text or picture messages) in a cellular communication system.

Background of the Invention

In the field of data communications, and particularly in cellular communications, communication via messaging in addition to voice communication has become very popular.

Messaging is an interactive service that offers user-to- user communication between individual users via storage units with 'store and forward', mailbox and/or message handling (e.g. information editing, processing and conversion) functions (source: ITU-T I.113).

In the cellular communications field, a number of

communication standards have been defined. One such standard is the global system for mobile communications (GSM), defined by the European Telecommunication Standards Institute (ETSI). Within the GSM standard, a supplementary messaging service has been defined. This service is offered in addition to normal voice communication. This service is known as a short message service (SMS) and is often used for sending and receiving brief 'text' messages. A normal Latin SMS message is - 2 packed in seven-bit characters. A well-known problem with sending and receiving SMS messages is that they are limited to only '160' characters.

In order to provide a more useful SMS service, a technique referred to as 'Concatenated SMS' has been developed and also standardized. This is a method by which a user is able to send multiple SMS messages, each of approximately 160 characters in length, tag them together and send them as a single, large message.

Concatenated SMS is a well-known feature of GSM and standardised in the GSM specification 03.40 and will not be further described here.

An enhanced messaging service (EMS) has also been standardized by ETSI to provide improved features within the context of GSM communication. EMS messaging supports the transmission and reception of more complex and more memory hungry media such as, small images and sounds, etc. In a similar manner to SMS messaging, EMS messages can also be concatenated.

A primary difference between the message structure of a normal single SMS or EMS message and a concatenated SMS or EMS message comprising multiple SMS or EMS messages is that the concatenated SMS (or EMS) message incorporates header data in eight-bit data octets. The eight-bit header octets are generally referred to as the "user data header" (UDH). Thus, there is a problem associated with the data formatting of concatenated SMS or EMS messages in that the SMS message itself still comprises the sevenbit characters, but there are a number of eight-bit data blocks at the front of the message. - 3

Note that it is possible for a concatenated SMS to be received by a phone that is not capable of concatenating SMS messages, as long as it skips the unsupported fields in the UDH and the text starts correctly on a seven-bit boundary. It is known that a phone that is not capable of concatenating SMS or receiving EMS messages should not try to display these eight-bit header elements as characters, when it can only support seven-bit characters.

The standard way of approaching this formatting problem is for a programmer to include the required eight-bit elements in the header, and then calculate a number of "fill bits" to additionally include up to the point where the corresponding seven-bit boundary of the actual textual data should occur. Thus, if the header comprises four eight-bit characters (i.e. 32 bits), the corresponding seven-bit format would require five seven bit slots (i. e. 35 bits) with the remaining three bits unused (but must be set to 1 according to GSM 03.40). A known mechanism to perform this data formatting operation, to encode a concatenated SMS or EMS message, is illustrated in the flowchart 100 of FIG. 1.

A user of a wireless communication device such as a mobile phone first enters data such as text, via a user interface (UI), that (s)he wishes to be sent by a message service such as a GSM short message service (SMS) or an enhanced message service (EMS), as shown in step 105. A processor located within the phone then performs segmentation of the received userentered text in step and converts the segmented user-entered text into 7 bit data blocks/per entered character, as shown in step 115. The processor then starts to encode an eight-bit user data header (UDH) as a preliminary step to the encoding of the text message, as shown in step 120.

Once the eight-bit UDH has been encoded, in step 125, the processor calculates a number of fill-bits that will be required to align the eightbit UDH with the subsequent seven-bit text, to ensure that the message is encoded in accordance with GSM 03.40, as shown in step 125. The subsequent text of the message is then encoded (packed) after the UDH and any fill-bits in the normal manner to maintain septet alignment of the message, as in step 130.

The concatenated SMS or EMS message is then transmitted, as shown in step 135.

Hence, in order to perform this data format manipulation, to form a concatenated message taking into account 8-bit and 7-bit data elements, relatively complicated algorithms are used to carry out the respective calculations. In addition, similar calculations need to be repeated when (encoding) packing the different parts of the message. The inventor of the present invention has recognized and appreciated that this is inefficient and leads to greater opportunity for errors.

Furthermore, the manipulation of the concatenated SMS or EMS message structure, to compensate for and align correctly these two differing-bit length message formats, is somewhat complex.

Thus, there exists a need in the field of the present invention to provide a wireless communication unit and methods of generating and receiving messages, wherein the c abovementioned disadvantages associated with prior art arrangements may be alleviated.

Statement of Invention

In accordance with a first aspect of the present invention, there is provided a method for encoding that requires components within the message to maintain different bit-wise boundaries. The method comprises the steps of calculating a header length for concatenating two or more messages, applying textual data from the two or more messages to fill a second part of the concatenated message, and subsequently overlaying header data to a first part of the concatenated message.

In accordance with a second aspect of the present invention, there is provided a storage medium, as claimed in Claim 9.

In accordance with a third aspect of the present invention, there is provided a wireless communication system, as claimed in Claim 10.

In accordance with a fourth aspect of the present invention, there is provided a wireless communication unit, as claimed in Claim 11.

In accordance with a fifth aspect of the present invention, there is provided a wireless communication unit. The wireless subscriber communication unit comprises a transmitter for transmitting a concatenated message and a signal processing function. The signal processor function comprises a message generation 6 - function that calculates a header length for concatenating two or more messages, applies textual data from the two or more messages to fill a second part of the concatenated message and overlays header data to a first part to form a concatenated message for transmission.

In this manner, the encoding of a concatenated message, particularly for GSM SMS or EMS messages, is performed in a more efficient manner than known encoding mechanisms.

In effect, the encoding (or packing) of a concatenated message is performed in reverse to the well-known encoding method. In essence, the inventive concepts of the present invention effectively propose to perform one calculation and derive the concatenated message structure from this calculation. The calculation yields a converted header length for the concatenated SMS or EMS message, which can be readily applied at the start of the message. Effectively, the accompanying textual data can then be applied to fill the latter part of the concatenated SMS or EMS message, thereby removing the present need to separately calculate a number of 'fill' bits.

Brief Description of the Drawings

FIG. 1 shows a flowchart of a known process employed by a wireless communication unit in the generation of a concatenated SMS or EMS message.

Exemplary embodiments of the present invention will now be described, with reference to the accompanying drawings, in which: / FIG. 2 illustrates a block diagram of a wireless communication unit adapted to generate a concatenated SMS or EMS message, in accordance with a preferred embodiment of the invention; FIG. 3 illustrates a flowchart of a process employed by a wireless communication unit in the generation of a concatenated SMS or EMS message in accordance with a preferred embodiment of the invention; and FIG. 4 illustrates a series of data structures highlighting the generation of a concatenated SMS or EMS message in accordance with a preferred embodiment of the invention.

Description of Preferred Embodiments

Referring now to FIG. 2, a block diagram of a wireless communication unit, such as a mobile phone and often referred to as a mobile station (MS), is shown in accordance with a preferred embodiment of the invention.

The MS 200 contains an antenna 202 preferably coupled to a duplex filter, circulator or antenna switch 204 that provides isolation between receive and transmit chains within the MS 200.

The receiver chain, as known in the art, includes receiver front-end circuitry 206 (effectively providing reception, filtering and intermediate or base-band frequency conversion). The front-end circuit is serially coupled to a signal processing function 208. An output from the signal processing function 208 is provided to a c user interface 210, which in a receiving context comprises a suitable output device 232, such as a screen or flat panel display.

The receiver chain also includes received signal strength indicator (RSSI) circuitry 212, which in turn is coupled to a controller 214 that maintains overall subscriber unit control. The controller 214 may therefore receive bit error rate (BER) or frame error rate (PER) data from recovered information. The controller 214 is also coupled to the receiver front-end circuitry 206 and the signal processing function 208 (generally realised by a digital signal processor (DSP)). In some embodiments, the controller functionality may be implemented by the processor, as would be appreciated by a person skilled in the art.

The controller is also coupled to a memory device 216 that selectively stores operating regimes, such as decoding/encoding functions, synchronization patterns, code sequences, and the like. A timer 218 is operably coupled to the controller 214 to control the timing of operations (transmission or reception of time-dependent signals) within the MS 200, particularly with regard to transmitting and/or receiving a concatenated SMS or EMS message.

As regards the transmit chain, this essentially includes an input device 234, such as a keypad, of the user interface 210. The user interface 210 is coupled in series through transmitter/ modulation circuitry 222 and a power amplifier 224 to the antenna 202. The transmitter/ modulation circuitry 222 and the power - 9 - amplifier 224 are operationally responsive to the controller 214, and as such are used in the transmission of a concatenated SMS or EMS message.

A skilled artisan will appreciate that the signal processor function 208 in the transmit chain may be implemented as distinct from a processor in the receive chain. Alternatively, a single processor 208 may be used to implement processing of both transmit and receive signals, as shown in FIG. 2. Clearly, the various components within the MS 200 can be realised in discrete or integrated component form, with an ultimate structure therefore being merely dependent upon the prevailing design considerations.

In the context of receiving a concatenated SMS or EMS message, in accordance with the preferred embodiment of the present invention, the signal processing function 208 comprises an adapted SMS or EMS unpacking function 242.

The unpacking function 242 is operably coupled to the memory element 216 and upon unpacking a received concatenated SMS or EMS message, stores a copy of the user data header portion of the message in the memory element 216. The unpacking function 242 then unpacks the whole of the received 7bit concatenated SMS or EMS message and ignores a respective first UDH number of octets of this message. The unpacking function 242 then extracts the stored UDH from the memory element 216 and re-formats the received message by attaching a re formatted 8-bit UDH to the unpacked textual data. The expression 'textual data' is used hereinafter to comprise any data that is capable of being transmitted and received in messages. The unpacking function 242 then - 10 passes 236 the re- formatted concatenated SMS or EMS message to the display 232 of the user interface 210 for displaying to a user.

In the context of transmitting a concatenated SMS or EMS message, the signal processing function 208 comprises an adapted SMS or EMS concatenation function 244. The concatenation function 244 performs segmentation and reassembly of textual data that is entered via keypad 234 by a user. As known in the art, the concatenation function 244 segments the textual data in an 8-bit format and generates a corresponding 8-bit UDH.

In accordance with the preferred embodiment of the present invention, the concatenation function 244 passes the 8-bit formatted data to a message generation function 248. The message generation function 248 converts the two 8-bit data streams into a single 7-bit concatenated SMS or EMS message for transmission through the aforementioned transmitter chain. Although the previous step of segmentation and reassembly creates two 8-bit streams, one of characters and one of data to go in the user data header for each message, where both of these data streams are supplied to the message generation function 248, it is envisaged that alternative segmentation and number of data streams may be employed.

The preferred process for converting the two 8-bit data streams into a single 7-bit concatenated SMS or EMS message comprises calculating a header length for concatenating two or more messages) applying textual data from the two or more messages to fill a second part of the concatenated message; and subsequently overlaying (330) header data (442) to a first part of the concatenated message. This process is described in greater detail with respect to FIG. 3.

It is within the contemplation of the invention that the functionality of the controller 214 and/or processor 208 may be incorporated into, or distributed between, a number of elements, and need not be located solely in the either the controller 214 or processor 208.

More generally, an algorithm to generate or receive concatenated SMS or EMS messages, according to the preferred embodiment of the present invention, may be implemented in a subscriber communication unit in any suitable manner. For example, new apparatus may be added to an existing subscriber communication unit, or alternatively existing parts of a conventional communication unit may be adapted, for example by reprogramming one or more processors therein. As such, the required adaptation may be implemented in the form of processor-implementable instructions stored on a storage medium, such as a floppy disk, hard disk, programmable read only memory (PROM), random access memory (RAM) or any combination of these or other storage media.

Referring now to FIG. 3, a flowchart 300 illustrates a preferred method for encoding a message that requires components within the message to maintain different bit- wise boundaries, for example to encode textual data into a concatenated SMS or EMS message. In conjunction, FIG. 4 illustrates the data structures 400 employed in the preferred process of FIG. 3. A user of a wireless communication device, such as a mobile phone, first inputs, via a user interface (UI), textual data 410 that (s)he wishes to be sent by a data message service, such as a GSM short message service (SMS) or an enhanced message service (EMS), as shown in step 305. The textual data 410 comprises enough data characters to merit sending two or more messages, and thus a concatenated message needs to be sent. A processor located within the phone then performs segmentation of the received user- entered text in step 310.

Notably, a processor located within the phone then calculates a number of septets required for the octet- coded UDH, as shown in step 315. This number is then rounded up to form a complete septet. The processor then prefixes the textual data 410 with that number of octets, filled with 'FF' 422, illustrated in data structure 420 and as shown in step 320.

In addition, the processor then encodes the whole of the input buffer into a 7-bit format 430, as shown in step 325. The processor then overlays the 8-bit user data header (UDH) information 442 as a final step in the encoding of the text message 440, as shown in step 330.

In this manner, the UDH replaces the corresponding number of temporary 'FF' bits applied to the prefixed number of octets. Notably, therefore, there is no need to calculate and include a pre-determined number of 'fill'- bits 444, as the 7-bit text data has fully utilised its available bit- resource, effectively working back from the last character to be sent. The UDH has also fully utilised an appropriate amount of the 7-bit data resource in the incorporation of its 8-bit data. The concatenated 13 SMS or EMS message is then transmitted, as shown in step 335.

The above mechanism results in a more efficient way to pack a concatenated SMS or EMS message, as there is no requirement to calculate a number of 'fill'-bits. Thus, in effect, the text is first encoded (packed) into the message leaving sufficient space for the header. The header is then applied thereby removing the need for calculating a number of 'fill'-bits.

The inventive concepts are described in the context of GSM SMS or EMS messages. However, it is within the contemplation of the invention that alternative message formats can be used.

The preferred embodiment of the present invention is described with respect to a mobile phone comprising functionality to generate and /or receive messages.

However, it is within the contemplation of the invention that other wireless communication units capable of messaging, such as a personal data assistant (PDA), portable radio, laptop computer, etc. could benefit from the inventive concepts hereinbefore described.

It will be understood that the wireless communication unit and methods of generating and receiving messages, as described above, tend to provide one or more of the following advantages: (i) Encoding of a concatenated message is performed in a more efficient manner; (ii) A less complicated packing algorithm is used, as the packing algorithm works on all bits in septet-based messages (iii) The mechanism is less prone to programmer error; and (iv) Fewer processor instructions are used.

Whilst the specific and preferred implementations of the embodiments of the present invention are described above, it is clear that one skilled in the art could readily apply variations and modifications of such inventive concepts.

Thus, a wireless communication unit and methods of generating and receiving messages have been described wherein the aforementioned disadvantages associated with prior art means and methods have been substantially alleviated.

Claims

Claims 1. A method of encoding messages that require components within the

message to maintain different bit wise boundaries (300), the method characterized by the steps of: calculating (315) a header length for concatenating two or more messages; applying textual data from the two or more messages to fill a second part of the concatenated message; and subsequently overlaying (330) header data (442) to a first part of the concatenated message.
2. A method of encoding messages that require components within the message to maintain different bit- wise boundaries (300) according to Claim 1, wherein the step of calculating (315) a header length calculates a header conversion from a first bit format to a second bit format for transmitting.
3. A method of encoding messages that require components within the message to maintain different bit- wise boundaries (300) according to Claim 1 or Claim 2, wherein the step of calculating (315) comprises performing a single calculation and deriving a message structure (440) from the single calculation.
4. A method of encoding messages that require components within the message to maintain different bit- wise boundaries (300) according to Claim 2 or Claim 3, wherein the step of calculating (315) comprises calculating a number of septets required for transmitting an octet-coded header.
5. A method of encoding messages that require components within the message to maintain different bit- wise boundaries according to Claim 4, the method further characterized by the step of prefixing (320) textual data of the concatenated message with the calculated number of octets.
6. A method of encoding messages that require components within the message to maintain different bit- wise boundaries according to any preceding Claim, wherein the method is further characterized by the step of filling the first part of the concatenated message with fill bits prior to the step of overlaying a header.
7. A method of encoding messages that require components within the message to maintain different bit wise boundaries according to any preceding Claim, wherein the method is further characterized in that it is used in a short message service or an enhanced message service message.
8. A method of encoding messages that require components within the message to maintain different bit- wise boundaries according to any preceding Claim, wherein the method is further characterized in that it is used in a GSM or GPRS or Edge or UMTS context.
9. A storage medium storing processor-implementable instructions for controlling a processor to carry out the method of any of claims 1 to 8.
10. A wireless communication system adapted to facilitate the method steps of encoding messages that require components within the message to maintain different bit-wise boundaries of any of Claims 1 to 8.
11. A wireless subscriber communication unit adapted to perform the steps of encoding messages that require components within the message to maintain different bit wise boundaries according to any of Claims 1 to 8.
12. A wireless subscriber communication unit (200) comprising: a transmitter for transmitting a concatenated message; and a signal processing function (208); wherein the wireless subscriber communication unit (200) is characterized by: a message generation function (248) that calculates a header length for concatenating two or more messages, applies textual data from the two or more messages to fill a second part of the concatenated message and overlays header data (442) to a first part to form a concatenated message for transmission.
13. A wireless subscriber communication unit (200) according to Claim 12 further characterized in that the message generation function (248) calculates a header conversion from a first bit format to a second bit format for transmitting.
14. A wireless subscriber communication unit (200) according to Claim 12 or Claim 13 further characterized in that the message generation function (248) performs a single calculation and derives a message structure (440) therefrom.
15. A wireless subscriber communication unit (200) according to any of preceding Claims 12 to 14 further characterized in that the message generation function (248) calculates a number of septets required for transmitting an octet- coded header.
16. A wireless subscriber communication unit (200) according to Claim 15 further characterized in that the message generation function (248) prefixes textual data of the concatenated message with the calculated number of octets.
17. A wireless subscriber communication unit (200) according to any of preceding Claims 12 to 16 further characterized in that the message generation function (248) fills the first part of the concatenated message with fill bits prior to overlaying a header.
18. A wireless subscriber communication unit (200) according to any of preceding Claims 12 to 17 further characterized by: a receiver for receiving a concatenated message, such that the signal processing function (208) comprises an adapted message unpacking function (242); and a memory element (216) for receiving a copy of the data header, wherein the unpacking function (242) unpacks a whole of a received concatenated message and ignores a respective first number of octets of the message.
19. A wireless subscriber communication unit (200) according to Claim 18 further characterized by an unpacking function (242), which then formats a received message in a first bit format and extracts the data header from the memory element (216).
20. A wireless subscriber communication unit (200) according to any of preceding Claims 12 to 19 further characterized in that the unpacking function (242) then attaches re-formatted 8-bit data header to reformatted 8-bit textual data and passes (236) the re-formatted concatenated SMS or EMS message to a display (232) of a user interface (210) for displaying to a user.
21. A wireless subscriber communication unit (200) according to any of preceding Claims 12 to 17 further characterized in that it is used in a short message service or an enhanced message service message.
22. A wireless subscriber communication unit (200) according to any of preceding Claims 12 to 17 further characterized in that it is used in a GSM or GPRS or Edge or UMTS context.
23. A wireless subscriber communication unit (200) according to any of preceding Claims 12 to 17 further characterized in that the wireless subscriber communication unit (200) is one of: a cellular phone, a portable or mobile radio, a personal digital assistant or a laptop computer.
24. A wireless subscriber communication unit substantially as hereinbefore described with reference to, and/or as illustrated by, FIG. 2 of the accompanying drawings.
25. A method of encoding messages that requires components within the message to maintain different bit- wise boundaries substantially as hereinbefore described with reference to, and/or as illustrated by, FIG. 3 or FIG. 4 of the accompanying drawings.

25. A method of encoding messages that require components within the message to maintain different bit- wise boundaries substantially as hereinbefore described with reference to, and/or as illustrated by, FIG. 3 or FIG. 4 of the accompanying drawings.

Amendments to the claims have been filed as follows Al Claims 1. A method of encoding messages that requires components within the message to maintain different bit wise boundaries t300), the method characterized by the steps of: calculating (315) a header length for concatenating two or more messages; applying textual data from the two or more messages to fill a second part of the concatenated message; and subsequently overlaying (330) header data (942) to a first part of the concatenated message.

2. A method of encoding messages that requires components within the message to maintain different bit- wise boundaries (300) according to Claim 1, wherein the step of calculating (315) a header length calculates a header conversion from a first bit format to a second bit format for transmitting.

3. A method of encoding messages that requires components within the message to maintain different bit- wise boundaries (300) according to Claim l or Claim 2, wherein the step of calculating (315) comprises performing a single calculation and deriving a message structure (440) from the single calculation.

4. A method of encoding messages that requires components within the message to maintain different bit- wise boundaries (300) according to Claim 2 or Claim 3, wherein the step of calculating (315) comprises 2z calculating a number of septets required for transmitting an octet-coded header.

5. A method of encoding messages that requires components within the message to maintain different bit- wise boundaries according to Claim 4, the method further characterized by the step of prefixing (320) textual data of the concatenated message with the calculated number of octets.

6. A method of encoding messages that requires components within the message to maintain different bit- wise boundaries according to any preceding Claim, wherein the method is further characterized by the step of filling the first part of the concatenated message with fill bits prior to the step of overlaying a header.

7. A method of encoding messages that requires components within the message to maintain different bit wise boundaries according to any preceding Claim, wherein the method is further characterized in that it is used in a short message service or an enhanced message service message.

8. A method of encoding messages that requires components within the message to maintain different bit- wise boundaries according to any preceding Claim, wherein the method is further characterized in that it is used in a GSM or GPRS or Edge or UMTS context.

9. A storage medium storing processor-implementable instructions for controlling a processor to carry out the method of any of claims 1 to 8.

10. A wireless communication system adapted to facilitate the method steps of encoding messages that requires components within the message to maintain different bit-wise boundaries of any of Claims 1 to 8.

11. A wireless subscriber communication unit adapted to perform the steps of encoding messages that requires components within the message to maintain different bit wise boundaries according to any of Claims 1 to 8.

12. A wireless subscriber communication unit (200) comprising: a transmitter for transmitting a concatenated message; and a signal processing function (208); wherein the wireless subscriber communication unit (200) is characterized by: a message generation function (248) that calculates a header length for concatenating two or more messages, applies textual data from the two or more messages to fill a second part of the concatenated message and overlays header data (442) to a first part to form a concatenated message for transmission. 25:

13. A wireless subscriber communication unit (200) according to Claim 12 further characterized in that the: message generation function (248) calculates a header conversion from a first bit format to a second bit format for transmitting.

14. A wireless subscriber communication unit (200) according to Claim 12 or Claim 13 further characterized 2+ 19. A wireless subscriber communication unit (200) according to Claim 18 further characterized by an unpacking function (242), which then formats a received message in a first bit format and extracts the data header from the memory element (216).

20. A wireless subscriber communication unit (200) according to any of preceding Claims 12 to 19 further characterized in that the unpacking function (242) then attaches re-formatted 8-bit data header to reformatted 8-bit textual data to form a re-formatted concatenated SMS or EMS message and passes (236) the re-formatted concatenated SMS or EMS message to a display (232) of a user interface (210) for displaying to a user.

21. A wireless subscriber communication unit (200) according to any of preceding Claims 12 to 17 further characterized in that it is used in a short message service or an enhanced message service.

22. A wireless subscriber communication unit (200) according to any of preceding Claims 12 to 17 further characterized in that it is used in a GSM or GPRS or Edge or UMTS context.

23. A wireless subscriber communication unit (200) according to any of preceding Claims 12 to 17 further characterized in that the wireless subscriber communication unit (200) is one of: a cellular phone, a portable or mobile radio, a personal digital assistant or a laptop computer.

24. A wireless subscriber communication unit substantially as hereinbefore described with reference to, and/or as illustrated by, FIG. 2 of the accompanying drawings.