Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
2001-01-10
2004-07-13
Vincent, David (Department: 2661)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
C370S468000
Reexamination Certificate
active
06763028
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a transceiver and, more particularly, to a transmitting apparatus for dividing transmit data from each of a plurality of terminals into prescribed lengths of time, applying encoding processing to the divided data, multiplexing the encoded data thus obtained and transmitting the multiplexed signal, and to a receiving apparatus for demultiplexing multiplexed encoded data that has been received, applying decoding processing and sending the decoded data obtained to prescribed terminals.
In a CDMA (Code Division Multiple Access) mobile communications system, a base station spread-spectrum modulates control information and user information of multiple users using respective ones of different spreading code sequences, multiplexes and transmits the information, and each of a number of mobile stations transmits and receives information upon spreading and de-spreading the information using spreading codes specified by the base station.
FIG. 17
is a block diagram showing the structure of a mobile station according to the prior art. During reception, a radio unit
1
subjects a high-frequency signal received from an antenna ANT
R
to a frequency conversion (RF→IF conversion) to obtain a baseband signal. A quadrature detector
2
subjects the baseband signal to quadrature detection and outputs in-phase component (I component) data and quadrature component (Q component) data. A/D converters
3
a,
3
b
convert the I-component and Q-component signals, respectively, to digital signals, and the digital signals enters a search
4
and respective ones of fingers
5
1
-
5
4
. If a direct sequence signal (DS signal) that has experienced multipath effects enters, the searcher
4
executes autocorrelation processing using a matched filter (not shown), detects multipaths and inputs, to the fingers
5
1
-
5
4
, despreading-start timing data and delay-time adjustment data for the various paths.
Each of the fingers
5
1
-
5
4
has a despreader/delay-time adjustment unit
5
a
for performing dump integration by subjecting a direct wave or a delayed wave that arrives via a prescribed path to despread processing using a code identical with the spreading code, and for subsequently applying delay processing that conforms to the path and outputting a pilot signal (reference signal) and information signal; a phase compensator (channel estimation unit)
5
b
for averaging voltages of the I and Q components of the pilot signal over a prescribed number of slots and outputting channel estimation signals It, Qt; and a synchronous detector
5
c
for restoring the phases of despread information signals I′, Q′ to the original phases based upon a phase difference &thgr; between a pilot signal contained in a receive signal and an already existing pilot signal. More specifically, the channel estimation signals It, Qt are cosine and sine components of the phase difference &thgr;, and therefore the synchronous detector
5
c
demodulates the receive information signal (I,Q) (performs synchronous detection) by applying phase rotation processing to the receive information signal (I′,Q′) in accordance with the following equation using the channel estimation signal (It,Qt):
(
I
Q
)
=
(
It
Qt
-
Qt
It
)
(
I
′
Q
′
)
A rake combiner
6
combines signals output from the fingers
5
1
-
5
4
and outputs the combined to a decoding processor (channel decoder)
7
.
The decoding processor
7
subjects the input signal to error correction processing, decodes the original transmit data and stores the decoded data in a receive buffer
8
. A data selector
9
inputs the decoded data, which has been stored in the receiver buffer
8
, to prescribed terminal equipment (TE). Examples of the terminal equipment TE are a telephone
10
, a facsimile transceiver
11
, a personal computer
12
and an ISDN terminal
13
. The telephone
10
is constituted by a voice codec
10
a,
a speaker
10
b
and a microphone
10
c
and is permanently connected to the data selector
9
. The facsimile transceiver
11
, personal computer
12
and ISDN terminal
13
, however, are connected to the data selector
9
selective via an adapter
14
′.
During transmission, the data selector
9
stores transmit data, which enters from an originating terminal, in a transmit buffer
14
, and an encoding processor (channel encoder)
15
subjects the transmit data to encoding processing and outputs the encoded data as in-phase component data. A control signal generator
16
outputs control data, such as a pilot signal, as quadrature-component data at a fixed symbol speed. A QPSK spreader
17
subjects the entered in-phase component (I-channel component) and quadrature-phase component (Q-channel component) to spread-spectrum modulation using a prescribed spreading code, converts the digital modulated signals to analog signals and inputs the analog signals to a QPSK quadrature modulator
18
. The latter subjects the I-channel and Q-channel signals to QPSK quadrature modulation, and a radio transmitter
19
frequency-converts (IF→RF) the baseband signal from the quadrature modulator
18
to a high-frequency signal, performs high-frequency amplification and transmits the amplified signal from an antenna ANT
T
.
FIG. 18
is a diagram useful in describing the frame format of an upstream signal from a mobile station to a base station. One frame has a length of 10 ms and is composed of 15 slots S
0
to S
1
4
. User data is mapped to the I channel of QPSK modulation and control data is mapped to the Q channel of QPSK modulation. The number n of bits in each slot in the I channel for user data varies in dependence upon symbol speed. Each slot in the Q channel for control data is composed of ten bits and the symbol speed is a constant 15 Kbps.
FIG. 19
is a diagram useful in describing the frame format and slot arrangement of a downstream signal from a base station to a mobile station. One frame has a length of 10 ms and is composed of 15 slots S
0
to S
14
. Each slot contains a mixture of user data Data
1
, Data
2
and control data TPC, TFCI, PILOT. The data in each slot is distributed in turns to the I channel and Q channel of QPSK quadrature modulation one bit at a time, after which spread-spectrum modulation and quadrature modulation is applied, frequency conversion is carried out and the resultant signal is transmitted to the mobile station.
Encoding Processing According to the Prior Art
In order to apply channel coding to continuous data sent from terminal equipment TE or the like at the time of transmission in the conventional mobile radio unit described above, it is required that the continuous data be delimited into prescribed processing units (10-ms intervals or the like) and subjected to channel coding in the prescribed units of processing. For example, if 64-Kbps data is delimited in increments of 10 ms and encoding processing is applied every 640 bits, operation will be as shown in FIG.
20
. Specifically, the terminal equipment TE sends data continuously but the mobile radio unit delimits the input data into units of processing (10-ms increments) and applies channel coding to data that has been delimited in 10-ms increments.
In this case, as shown in
FIG. 21
, the speed of data sent from the terminal equipment TE and processing speed on the encoding side generally have different clocks. In a mobile radio unit, speed up to the writing of data to the transmit buffer
14
depends upon speed on the side of the terminal equipment TE, but speed following the read-out of data from the transmit buffer
14
and the application of encoding processing is made high in order to minimize processing delay. If voice is taken as an example, the problem of echo occurs when the processing delay is too long. Accordingly, encoding processing is executed at high speed to minimize processing delay up to the wireless transmission of the voice data. In the case shown in
FIG. 21
, data is input from the terminal equipment TE at a bit rate of 64 Kbps, and the encoding processor
15
reads
Fujitsu Limited
Katten Muchin Zavis & Rosenman
Vincent David
LandOfFree
Transceiver apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Transceiver apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Transceiver apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3218783