Pulse or digital communications – Systems using alternating or pulsating current – Plural channels for transmission of a single pulse train
Reexamination Certificate
1998-09-11
2001-10-30
Chin, Stephen (Department: 2734)
Pulse or digital communications
Systems using alternating or pulsating current
Plural channels for transmission of a single pulse train
C375S213000, C370S529000
Reexamination Certificate
active
06310923
ABSTRACT:
BACKGROUND
1. Technical Field
The present application relates generally to a mobile communications system and, in particular, to a device and method for encoding transmission data to achieve frequency diversity.
2. Description of the Related Art
Generally, in a mobile communications system, voice or data is subject to channel encoding for radio transmission and reception. On a forward link, for example, voice or data to be transmitted is channel-encoded and modulated using modulation techniques such as QPSK (Quadrature Phase Shift Keying). Channel encoding is generally performed for data transmission in a single frequency, and encoded symbols are BPSK (Binary Phase Slift Keying)/QPSK modulated prior to transmission. If a plurality of frequencies and phase channels are available to a user for high-speed data transmission, however, there is a need for assigning transmission data symbols to the plurality of channels.
Conventionally, data symbols are distributed to a plurality of channels for transmission. Advantageously, this method enables optimal data transmission capacity for each channel, but has limitations in recovering data due to possible channel failure or loss of transmission data. The lost data may be recovered by reinforcing data encoding, but with a decrease in transmission efficiency on multiple channels. In addition, when a channel is or remains defective, the channel is either not used or less frequently used until it is recovered. Therefore, communication service quality becomes poor beyond remedy.
These problems can be solved by transmitting the same data on a plurality of frequencies and phase channels. Despite possible failures in some of channels, the data transmitted on the other channels are safe, thereby providing a reliable communication link. Unfortunately, this method significantly decreases channel use efficiency. In particular, since channel encoding and assignment of frequencies and phase channels are independently performed in the conventional technology, it is impossible to consider channel use efficiency when performing data encoding.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a device and method for converting channel-encoded symbols to code words, taking into consideration channel use efficiency and characteristics of a plurality of frequencies and phase channels, and transmitting the code words via a plurality of channels in a mobile communications system.
It is another object of the present invention to provide a device and method for detecting a code set with a desired minimum distance between code words in order to convert transmission data to code words in a mobile communications system.
It is a further object of the present invention to provide a device and method for selecting the best code set from a plurality of detected code sets in a mobile communications system, and transmitting the selected code set.
To achieve these and other objects, a method is provided for generating a code set in a mobile communications system having Nf frequency channels and Np phase channels. In the method, a code length Nc is obtained by Nf×Np, a minimum distance Nd between codewords in a code set and frequency diversity Nfd are determined, code sets are detected according to Nc, Nd, and Nfd, a code set is selected, which shows such a Hamming distance distribution among code words that minimize demodulation errors from the detected code sets, and the code set is stored in a mapping table of a demodulator.
These and other objects, features and advantages of the present invention will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings.
REFERENCES:
patent: 5305352 (1994-04-01), Calderbank et al.
patent: 5479448 (1995-12-01), Seshadi
patent: 5825807 (1998-10-01), Kumar
patent: 6115427 (2000-09-01), Calderbank et al.
Francois Gagnon, and David Haccoun, on the Performance of Error Control Coding with Diversity for Mobile Channels, IEEE 1992, pp. 488-495.*
Guilermo E. Atkin, and Hector P. Corrales, An Efficient Modulation/Coding Sheme for MFSK Systems on Bandwidth Constrained Channels, IEEE 1989, pp. 1396-1401.
Ahn Jae-Min
Chung Ha-Bong
Kang Hee-Won
Kim Young-Ky
Kong Seung-Hyun
Al-Beshrawi Tony
Chin Stephen
Dilworth & Barrese LLP
Samsung Electronics Company, Ltd.
LandOfFree
Device and method for data encoding and frequency diversity... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device and method for data encoding and frequency diversity..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device and method for data encoding and frequency diversity... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2566880