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Group Encoding Method for Infrared Communication

IP.com Disclosure Number: IPCOM000060240D
Original Publication Date: 1986-Mar-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Milling, PE: AUTHOR

Abstract

A technique is described whereby the transmission of data through the use of infrared technology is enhanced through the use of group encoding. The technique described herein utilizes a group encoding method to reduce the power requirement of infrared light-emitting diodes (LEDs), thereby not only decreasing the transmission time but prolonging the life of the infrared LEDs. In conventional infrared transmission using Manchester encoding, the encoded information requires the transmitter to be pulsed on for half a bit time (during the first or second half of the bit cell, depending on the value of the bit) for each transmitted bit. Typically, the infrared LED cannot be turned on and off any faster than once per microsecond period.

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Group Encoding Method for Infrared Communication

A technique is described whereby the transmission of data through the use of infrared technology is enhanced through the use of group encoding. The technique described herein utilizes a group encoding method to reduce the power requirement of infrared light-emitting diodes (LEDs), thereby not only decreasing the transmission time but prolonging the life of the infrared LEDs. In conventional infrared transmission using Manchester encoding, the encoded information requires the transmitter to be pulsed on for half a bit time (during the first or second half of the bit cell, depending on the value of the bit) for each transmitted bit. Typically, the infrared LED cannot be turned on and off any faster than once per microsecond period. By using the group method of transmission, the transmission time can almost be halved (5/8 compared to 8/8) and also the worst-case power consumption required by the LEDs is reduced in half (two on periods per nibble, or four data bits). The method involves the translation of original data in m-bit groups into corresponding n-bit groups, so that the coding of the n-bit groups is selected to minimize the appearances of one bits, which turn on the LEDs. In the figure, four- and five-bit codes are shown. Group encoding provides the four data bit codes to be translated into five data bit codes. There are 16 four-bit patterns and 32 five-bit patterns. The user is free to choose which five-bit p...