Methods and apparatus for compressing and decompressing paging data

• US 5,396,228 A
• Filed: 01/16/1992
• Issued: 03/07/1995
• Est. Priority Date: 01/16/1992
• Status: Expired due to Term

• Current Assignee: Skytel Corporation (Bell Industries Incorporated)
• Original Assignee: Mobile Telecommunications Technologies, LLC (Mobitex Technology AB)
• Inventors: Garahi, Masood
• Primary Examiner(s): Yusko, Donald J.
• Assistant Examiner(s): MERZ, EDWARD W
• Application Number:
  US07/821,454
• Time in Patent Office: 1,146 Days
• Field of Search: 341/173, 341/178, 341/106, 380/42, 380/43, 379/56, 379/57, 375/122, 371/2.1, 371/2.2, 340/825.44, 340/311.1
• US Class Current: 340/7.53
• CPC Class Codes: G08B 5/227 with call or message storage means
• CPC Class Codes: H04W 88/187 using digital or pulse address codes

Abstract

A system and method for encoding and decoding page messages includes an encoder for encoding and classifying each word of the page message. Words found in one of one or more word dictionaries are encoded into corresponding compressed codes. A header code identifying either the dictionary or the classification of the word is associated with each word. The encoded message is transmitted to a page receiver where each word is decoded based upon the header code associated therewith. If the header code indicates that the word is a compressed code stored in a word dictionary, the compressed code is used to retrieve the word from the dictionary. If the header code indicates that the word is not stored in a word dictionary, the words are decoded differently, depending upon their classification.

Claims

1. A paging system, comprising:

a paging system control terminal for preparing a page message, including,

a first encoding dictionary containing a first plurality of selected words;

a second encoding dictionary containing a second plurality of selected words different from said first plurality of selected words contained in said first encoding dictionary, said second plurality of words being larger than said first plurality of words;

means for separating words of said page message;

means for comparing each word of said page message with said one or more words in said first and second dictionaries;

means, responsive to a match between said each word of said page message and said one or more words in said first and second dictionaries, for reformatting said page message using a compressed code corresponding to each said matched word of said page message; and

means for combining a selected header code identifying either said first or second dictionary and the compressed code corresponding to each matched word of the page message;

a transmitter for transmitting said reformatted page message; and

a page receiver, including,

first and second dictionaries similar to said first and second dictionaries of said paging system control terminal;

means, responsive to each compressed code in said reformatted page message, for retrieving a corresponding word from one of said first and second dictionaries; and

means for displaying each of said retrieved words.

2. A paging system for transmitting and receiving a series of bits that correspond to a selected message, the message including a plurality of words, the paging system comprising:

means for separating the selected page message into the plurality of words;

means, including at least one encoding dictionary, for encoding at least one of said plurality of words into a preselected compressed code;

means for transmitting an encoded message, including the compressed code corresponding to said at least one of said plurality of words;

means for receiving said encoded message;

means, including at least one decoding dictionary, for decoding each encoded word of the encoded message;

wherein, said encoding means includes;

means for comparing each word of said message with said plurality of words in said at least one encoding dictionary; and

means, responsive to said comparing means, for combining a selected header code identifying said encoding dictionary and said compressed code.

3. The paging system according to claim 2 further comprising means for classifying each word other than said at least one of said plurality of words of said page message, and means for associating with each classified word a header code identifying the classification of said word.

4. The paging system according to claim 3, wherein said classifying means includes means for recognizing a predetermined series of bits representing a telephone number;

and

means for encoding said predetermined series of bits into a smaller number of bits and combining said header code with said smaller number of bits.

5. The paging system according to claim 3, wherein said classifying means includes means for recognizing a predetermined series of bits representing an integer;

and

means for encoding said predetermined series of bits into a smaller number of bits and combining said header code with said smaller number of bits.

6. The paging system according to claim 3, wherein said classifying means includes means for recognizing a predetermined series of bits representing a literal alpha-character word;

and

means for encoding said predetermined series of bits into a smaller number of bits and combining said header code with said smaller number of bits.

7. The paging system according to claim 2, wherein said decoding means includes means, responsive to each of said header codes for decoding encoded words in accordance with different techniques depending upon the associated header code.

8. A paging system for transmitting and receiving a series of bits that correspond to a selected message, the message including a plurality of words, the paging system comprising:

means for separating the selected page message into the plurality of words;

means for encoding at least one of said plurality of words into a preselected compressed code;

means for transmitting an encoded message, including the compressed code corresponding to said at least one of said plurality of words;

means for receiving said encoded message;

means, including at least one decoding dictionary, for decoding each encoded word of the encoded message;

wherein said means for encoding includes;

a first encoding dictionary containing a first plurality of selected words; and

a second encoding dictionary containing a second plurality of selected words different from said first plurality of selected words contained in said first encoding dictionary, said second plurality of words being larger than said first plurality of words.

9. A paging system for transmitting and receiving a series of bits that correspond to a selected message, the message including a plurality of words, the paging system comprising:

means for separating the selected page message into the plurality of words;

means, including at least one encoding dictionary, for encoding at least one of said plurality of words into a preselected compressed code;

means for transmitting an encoded message, including the compressed code corresponding to said at least one of said plurality of words;

means for receiving said encoded message;

means, including at least one decoding dictionary, for decoding each encoded word of the encoded message;

wherein said means for encoding includes;

means for combining a first header code with each of said preselected compressed codes to indicate that said compressed codes are stored in said at least one encoding dictionary;

means for classifying each word of said page message other than said at least one of said plurality of words, and

means for combining a second header code with a code for each of said words of said page message other than said at least one of said plurality of words to identify their classification.

10. In a paging system including a paging system control terminal and a page receiver, a paging method for encoding and decoding a page message, the method comprising the steps of:

storing in said paging system control terminal at least one dictionary associating one or more words with corresponding compressed codes;

separating words of a page message;

comparing each word of said page message with said one or more words in said at least one dictionary;

reformatting said page message using a compressed code and a header code identifying said at least one dictionary, said compressed code corresponding to a matched word of said page message when said comparing step determines that there is a match between a word of said page message and said one or more words in said at least one dictionary;

transmitting said reformatted page message; and

storing in a page receiver at least one dictionary similar to said at least one dictionary of said paging system control terminal;

retrieving a word from said at least one dictionary in said page receiver corresponding to each compressed code in said reformatted page message; and

displaying each of said retrieved words.

11. In a paging system for transmitting a series of bits that correspond to a page message, said page message including a plurality of words, a method for encoding said page message comprising the steps of:

separating said page message into the plurality of words;

encoding at least one of said plurality of words into a preselected compressed coding using two or more different encoding dictionaries; and

transmitting an encoded page message, including the compressed code corresponding to said at least one of said plurality of words and a header code identifying one of said two or more different dictionaries.

12. A paging method according to claim 11, further comprising the steps of:

classifying each word of said page message other than said at least one of said plurality of words, and

associating with each classified word a header code identifying the classification of said word.

13. A paging method according to claim 12, wherein said step of classifying includes the step of:

recognizing a predetermined series of bits representing a telephone number.

14. The paging method according to claim 12, wherein said step of classifying includes the step of:

recognizing a predetermined series of bits representing an integer.

15. The paging method according to claim 12, wherein said step of classifying includes the step of:

recognizing a predetermined series of bits representing a literal alpha-character word.

16. The paging method according to claim 11, wherein said step of decoding includes the step of:

decoding said encoded words in accordance with different techniques depending upon an associated header code.

17. The paging method according to claim 13, further comprising the steps of encoding said predetermined series of bits into a smaller number of bits, and combining said header code with said smaller number of bits.

18. The paging method according to claim 14, further comprising the steps of encoding said predetermined series of bits into a smaller number of bits, and combining said header code with said smaller number of bits.

19. The paging method according to claim 15, further comprising the steps of encoding said predetermined series of bits into a smaller number of bits, and combining said header code with said smaller number of bits.

20. In a paging system for transmitting a series of bits that correspond to a page message, said page message including a plurality of words, a method for encoding said page message comprising the steps of:

separating said page message into the plurality of words;

encoding at least one of said plurality of words into a preselected compressed code using at least one encoding dictionary;

combining a first header code with each of said preselected compressed codes to indicate that said compressed codes are stored in said at least one encoding dictionary;

classifying each word of said page message other than said at least one of said plurality of words; and

combining a second header code with a code for each of said words of said page message other than said at least one of said plurality of words to identify their classification.

21. The paging method according to claim 20, further comprising the step of:

analyzing said first and second header codes;

decoding each preselected compressed code using said at least one decoding dictionary when a header code is said first header code; and

decoding each of said codes for said words of said page message other than said at least one of said plurality of words without using said at least one decoding dictionary when a header code is said second header code.

22. A paging system for compressing and transmitting a page message including a plurality of words, comprising:

a first dictionary storing a first set of words and corresponding compressed codes;

a second dictionary storing a second set of words and corresponding compressed codes;

means for comparing a word of said page message with each word in said first set of words in said first dictionary;

means for transmitting a corresponding compressed code for one of said words in said first dictionary when said word of said page message matches said one of said words in said first dictionary;

means for comparing said word of said page message with each word in said second set of words in said second dictionary when said word of said page message does not match one of said words in said first set of words in said first dictionary;

means for transmitting a corresponding compressed code for one of said words in said second dictionary when said word of said page message matches said one of said words in said second dictionary; and

means for converting said word of said page message to an encoded word when said word of said page message does not match one of said words in said second set of words in said second dictionary.

23. A method of compressing and transmitting a page message including a plurality of words, comprising the steps of:

storing a first set of words and corresponding compressed codes in a first dictionary;

storing a second set of words and corresponding compressed codes in a second dictionary;

comparing a word of said page message with each word in said first set of words in said first dictionary;

transmitting a corresponding compressed code for one of said words in said first dictionary when said word of said page message matches said one of said words in said first dictionary;

comparing said word of said page message with each word in said second set of words in said second dictionary when said word of said page message does not match one of said words in said first set of words in said first dictionary;

transmitting a corresponding compressed code for one of said words in said second dictionary when said word of said page message matches said one of said words in said second dictionary; and

converting said word of said page message to an encoded word when said word of said page message does not match one of said words in said second set of words in said second dictionary.

24. A method of decompressing a page message comprising the steps of:

storing a first set of words and corresponding compressed codes in a first dictionary;

storing a second set of words and corresponding compressed codes in a second dictionary;

comparing a compressed code in the page message with one or more compressed codes in said first dictionary;

displaying the corresponding word if the compressed code matches a compressed code found in the first dictionary;

comparing the compressed code to compressed codes in the second dictionary if the compressed code does not match any compressed codes in the first dictionary; and

displaying a corresponding word if the compressed code matches a compressed code in the second dictionary.