Multiplex communications – Communication over free space – Combining or distributing information via code word channels...
Reexamination Certificate
1999-08-06
2003-03-18
Chin, Wellington (Department: 2664)
Multiplex communications
Communication over free space
Combining or distributing information via code word channels...
C375S146000, C455S126000
Reexamination Certificate
active
06535500
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a transmitter of a mobile station in a CDMA (Code Division Multiple Access) communications system, and more particularly to such transmitter for controlling the channel gain of a transmitted binary signal and integer-spreading it.
2. Description of the Related Art
Referring to
FIG. 1
for illustrating the structure of the transmitter of a mobile station in a conventional CDMA communications system, the orthogonal modulator
111
multiplies the transmitted signal of each channel by a corresponding orthogonal code of the channel to orthogonal spread the channel. The orthogonal code may be a Walsh code. The long PN (pseudo-noise) code spreader
113
and short PN code spreader
115
spread the transmitted signal of each channel modulated with the orthogonal code. The long code is for identifying the mobile station, and the short code is for identifying the base station. The base band filter
117
filters the spread transmitted signal into the base band. The modulator
119
modulates the transmitted signal of the base band with a carrier wave.
Such a conventional transmitter of the mobile station spreads binary data which has not been adjusted for channel gain after orthogonal modulation, and then filters the spread binary data, so that it requires a circuit for binary mapping to obtain binary data. Furthermore, additional multipliers are necessary for spreading the obtained binary data in long code and short code, complicating the hardware structure. Although
FIG. 1
does not show the additional parts for gain adjustment, it will be readily noted that the circuit for binary mapping is required including additional multipliers.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a CDMA mobile phone with a simplified circuit for adjusting the channel gain, and method therefor.
It is another object of the present invention to provide a CDMA mobile phone with a simplified circuit for band spreading, and method therefor.
It is another object of the present invention to provide a CDMA mobile phone with a circuit for band spreading with adjustment of the channel gain without binary mapping.
According to the present invention, a transmitter provided in the mobile station of the CDMA communications system comprises an orthogonal modulator for orthogonal-modulating channel-coded transmission signals with the orthogonal codes of corresponding channels, a gain control value generator for obtaining the complement of a first channel gain control value corresponding to each channel to generate a second channel gain control value, and a selection circuit for selecting one of the first and second channel gain control values by the orthogonal-modulated signals.
The present invention will now be described more specifically with reference to the drawings attached only by of example.
REFERENCES:
patent: 5159608 (1992-10-01), Falconer et al.
patent: 5204874 (1993-04-01), Falconer et al.
patent: 5629955 (1997-05-01), McDonough
patent: 5777990 (1998-07-01), Zehavi et al.
patent: 5940434 (1999-08-01), Lee et al.
Chin Wellington
Dilworth & Barrese LLP
Samsung Electronics Co,. Ltd.
Schultz William
LandOfFree
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