Intelligent encoding method for wireless data communication and control

• US 6,516,035 B1
• Filed: 04/07/2000
• Issued: 02/04/2003
• Est. Priority Date: 04/07/2000
• Status: Expired due to Term

• Current Assignee: Actisys Corp.
• Original Assignee: Actisys Corp.
• Inventors: Wang, Lichen, Yeh, Keming W.
• Primary Examiner(s): TSE, YOUNG TOI
• Application Number:
  US09/545,229
• Time in Patent Office: 1,033 Days
• Field of Search: 375/242, 375/246, 375/253, 370/445, 370/447, 370/449, 370/461, 370/462, 340/825.5, 341/59, 341/60, 341/67, 382/245
• US Class Current: 375/253
• CPC Class Codes: H03M 5/145 Conversion to or from block codes or representations thereof
• CPC Class Codes: H04L 25/4908 using mBnB codes

Abstract

A method includes a data encoding scheme that has a run length limit of (1,6) and a 25% duty cycle. With error correction, the method achieves an effective run length limit of (2,9). The method can be used in conjunction with a packetized communication protocol to allow multiple controllers to communicate with multiple peripheral devices in a wireless data network. Peripheral devices include pointing devices, keyboards and game pads.

Claims

1. A method for encoding a bit stream into symbols for transmitting over a wireless communication link, comprising:

providing a state machine having a first state, a second state and a third state, wherein said first state, said second state and said third state are associated with a first group of symbols, a second group of symbols and a third group of symbols, respectively, wherein selected symbols from said first group of symbols, said second group of symbols and said third group of symbols are designated state transition symbols;

initializing said state machine to said first state;

until all bits in said bit stream are encoded, repeating the steps of;

(a) removing from said bit stream a predetermined number of bits;

(b) when said state machine is in said first state, encoding said bits removed from said bit stream into a symbol selected from said first group of symbols according to a predetermined map, and entering said second state when said selected symbol is one of said designated state transition symbols;

(c) when said state machine is in said second state, encoding said bits removed from said bit stream into a symbol selected from said second group of symbols according to said predetermined map, and when said selected symbol is one of said designated state transition symbols, entering said third state when said selected symbol has a ratio of first logic value bits to second logic value bits that is less than a predetermined value; and

(d) when said state machine is in said third state, encoding said bits removed from said bit stream into a symbol selected from said third group of symbols according to said predetermined map, and when said selected symbol is one of said designated state transition symbols, entering said second state.

2. A method as in claim 1, wherein each symbol in said first group of symbols has a ratio of first logic value bits to second logic value bits equal to said predetermined value, and each symbol in said third group of symbols has a ratio of first logic value bits to second logic value bits greater than said predetermined value.

3. A method as in claim 1, wherein no symbol in said first group of symbols, said second group of symbols and said third group of symbols has consecutive first logic value bits.

4. A method as in claim 1, wherein a designated state transition symbol in said first group of symbols and another symbol in said first group of symbols, when concatenated, form a bit sequence that has two first logic value bits separated by less than a predetermined number of second logic value bits.

5. A method as in claim 1, wherein a designated state transition symbol in said second group of symbols and a symbol in said third group of symbols, when concatenated, form a bit sequence that has a ratio of first logic value bits to second logic value bits equal to said predetermined value.

6. A method as in claim 1, wherein said predetermined value is 25%.

7. A method as in claim 1, wherein said first group of symbols, said second group of symbols, and said third group of symbols form a code dictionary with a run length limit of (1, 6).

8. A method as in claim 7, wherein said code dictionary includes error correction capability to extend said run length limit.

9. A method as in claim 1 further comprising providing a decoder, said decoder, upon receiving a symbol not in said first group of symbols, said second group of symbols and said third group of symbols, provides an output value corresponding to decoding a symbol having a Hamming distance less than a said predetermined value.

10. A wireless communication system comprising:

a controller capable of sending a polling packet having an identification field; and

a plurality of devices each assigned a different identification value, capable of sending a response packet in response to said polling packet when a value in said identification field matches said identification value;

wherein said controller and each of said devices comprise a transmitter capable of encoding a bit stream according to said method of claim 1.

11. A wireless communication system as in claim 10, wherein said method is used in conjunction with a sub-carrier frequency.

12. A wireless communication system as in claim 11, wherein said sub-carrier frequency is 56 KHz.

13. A wireless communication system as in claims 10, wherein each transmitter receives data in a parallel format and transmits data serially.

14. A wireless communication system as in claim 13, said transmitter further comprising a clock generator circuit.