Pulse or digital communications – Spread spectrum
Reexamination Certificate
1999-11-30
2004-07-06
Chin, Stephen (Department: 2634)
Pulse or digital communications
Spread spectrum
C375S142000, C375S144000, C375S148000, C375S150000, C375S343000, C375S346000
Reexamination Certificate
active
06760360
ABSTRACT:
BACKGROUND OF THE INVENTION
This patent application claims priority based on a Japanese patent application, H11-46088 filed on Feb. 24, 1999, the contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates generally to cellular telephone systems. More particularly, the present invention concerns a novel and improved device and method for filtering signals received by base transceiver station or mobile terminal for cellular telephone systems or satellite mobile telephone systems employing spread spectrum communication techniques, capable of reducing size or scale of memory capacity and circuitry in base transceiver station and mobile terminals.
2. Description of the Related Arts
There has been known the use of code division multiple access (CDMA) modulation techniques which is one of several techniques for facilitating communications in which a large number of system users are present. Other multiple access communication system techniques, such as time division multiple access (TDMA), frequency division multiple access (FDMA) and AM modulation schemes such as amplitude companded single side-band (ACSSB) are known in the art. However the spread spectrum modulation technique of CDMA has significant advantages over these modulation techniques for multiple access communication systems. The use of CDMA techniques in a multiple access communication system is disclosed, for example, in U.S. Pat. No. 4,901,307, entitled “SPREAD SPECTRUM MULTIPLE ACCESS COMMUNICATION SYSTEM USING SATELLITE OR TERRESTRIAL REPEATERS”, of which the disclosure thereof is incorporated by reference.
In addition, the related art is also described in Japanese Patent Application No. Hei. 11-46088, from which the present application claims priority, and which is also incorporated herein by reference.
In the system, a base transceiver station receives SS (or spread spectrum) signals transmitted by each of the user terminals and identifies a particular user terminal by detecting a power level data of the received signals. For example, WO96-19048 discloses a circuit device for detecting the power level data of received signals.
FIG. 1
is a block diagram showing one example of a mobile cellular telephone system to which the received signal filtering device and method therefor according to the present invention is applicable. As shown in
FIG. 1
, a terminal user transmits and receives spread spectrum code signals by using a mobile cellular telephone
101
between a base transceiver station
102
through an antenna
103
. The base transceiver station
102
is provided with an open air receiver amplifier (OA-RA)
104
by which the received signals are amplified. The amplifier
104
connects to a base transceiver apparatus (BTS)
105
in which the amplified signals are demodulated and processed. The received signals may contain therein voice data, audio data, image data, moving image data, JPEG data, or MPEG data. Those signals are modulated before transmitted by means of the code division multiple access (CDMA) communication techniques, and the received radio signals are demodulated either at a base band signal processor (described later) of the mobile cellular telephone
101
or at the base transceiver apparatus (BTS) of the base transceiver station
102
.
On the other hand, another terminal user using a mobile cellular telephone
201
connecting to a personal computer PC receives SS (or spread spectrum) signals from and transmits SS signals to another base transceiver station
202
through an antenna
203
. Similar to the first base transceiver station
102
, the second base transceiver station
202
includes an open air receiver amplifier (OA-RA)
204
and a base transceiver apparatus (BTS)
205
having the same or similar function and operation.
Both the first and second base transceiver apparatus (BTS)
105
and
205
connect to a radio network controller equipment (RNC)
108
which is coupled to a multimedia signal processing equipment. The radio network controller equipment
108
coupling to a multimedia signal processing equipment (MPE)
110
and outputs signals to a mobile multimedia switching system (MMS)
115
.
FIG. 2
is a block diagram showing the base transceiver station
102
. As shown in
FIG. 2
, the base transceiver apparatus (BTS)
105
is provided with an amplifier block AMP and a modulation and demodulation block MDE. The amplifier block AMP includes a transmission power amplifier section (T-PA)
120
and an amplifier supervisory controller section (AMP-SC)
121
. On the other hand, the modulation and demodulation block MDE is provided with a transmitter and receiver section (TRX)
122
connecting both to the transmission power amplifier section (T-PA)
120
and the amplifier supervisory controller section (AMP-SC)
121
of the amplifier block AMP. Abase band signal processor section (BB)
123
connects to the transmitter and receiver section (TRX)
122
, and an HWY interface section (HWY-INT)
124
connects to the base band signal processor section (BB)
123
. The output of the HWY interface section (HWY-INF)
124
is transmitted to external devices (not shown) through a cable transmission passage.
Further, as shown in
FIG. 2
, a call processing controller section (CP-CNT)
125
connects to the transmitter and receiver section (TRX)
122
, and the supervisory controller section
126
(SV-CNT) connects to the base band signal processor section (BB)
123
. Further, an external interface section (EXT-INF)
127
coupling to the HWY interface section (HWY-INF)
124
is connected to external devices (not shown).
The transmitter and receiver section (TRX)
122
may be provided with a low-noise amplifier for amplifying the receiving and transmitting RF signals, and code-divides those signals into multiple signals. The transmitter and receiver section
122
further performs as an A/D converter for converting the base-band spread signals into digital or analog signals, which signals are quadrate-modulated to form RF signals.
The base band signal processor section (BB)
123
, on the other hand, modulates or demodulates the signals with the spectrum spread technology. Further, the base band signal processor section
123
processes the received signal for extracting a power level data therefrom, and takes an average of the signal to correctly, accurately detect a peak value of the power level data.
FIG. 3
is a schematic view showing a block diagram of a mobile terminal station, that is, a cellular telephone.
As shown in
FIG. 3
, the mobile terminal station includes a transmitter and receiver section (TRX)
130
which transmits and receives signals through an antenna
132
. The transmitter and receiver section
130
connects to a base band signal processor (BB)
134
in which the signals are modulated or demodulated. An external interface (EXT-INF)
136
connects to the base band signal processor
134
. All the sections are controlled by a controller (MS-CNT)
138
. The function and operation of the transmitter and receiver section (TRX)
130
, the base band signal processor (BB)
134
and the external interface (EXT-INF)
136
of the mobile terminal station are similar to those of the base transceiver station
102
, and the description is omitted here to avoid redundancy.
FIG. 4
is a schematic block diagram of a conventional receiver apparatus which receives spread spectrum (SS) signals modulated by means of the code division multiple access (CDMA) communication techniques.
When establishing a communication, signals from a user terminal cellular telephone must be first synchronized with a base transceiver station. Generally, a power level data is utilized to accomplish the synchronization.
As shown in
FIG. 4
, the receiver apparatus includes a complex correlating section
10
which receives spread spectrum signals of I
D
phase and Q
D
phase which are previously quadrate-modulated, takes places a reverse-spread operation for the received signals, and outputs the reverse-spread signals to a power extracting section
12
as received signals consisting o
Chin Stephen
Kokusai Electric Co. Ltd.
Odom Curtis
LandOfFree
Device and method for filtering received signals for mobile... 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 filtering received signals for mobile..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device and method for filtering received signals for mobile... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3238741