Telecommunications – Transmitter and receiver at separate stations – Frequency or phase modulation
Reexamination Certificate
1998-07-14
2001-02-27
Hunter, Daniel S. (Department: 2749)
Telecommunications
Transmitter and receiver at separate stations
Frequency or phase modulation
C455S059000, C375S260000
Reexamination Certificate
active
06195534
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a communication method, a transmitter, a receiver, and a cellular radio communication system, and more particularly, is applicable to a portable telephone system.
2. Description of the Related Art
Conventionally, in the field of radio communication, a combination of high priority data and low priority data is generally transmitted. Such a typical digital radio communication system that a combination of high priority data and low priority data is transmitted will be explained below. In the following explanation, one frame of transmission data is composed of the high priority data and the low priority data, and the transmission data for one frame is transmitted by one transmission slot. Note that frame means data units in the processing of digital data, and slot means data units in the transmitting of digital data.
In this radio communication system, two types of information are transmitted by one frame as shown in
FIG. 1
, so as to divide one frame into a high priority field and a low priority field. The high priority data is stored in the high priority field and the low priority data is stored in the low priority field. In this case, not only information bits of the data are to be stored, but also error detection and correction bits are stored in each field. Thereby, the receiving side can detect and correct errors of the received information bits by using the error detection and correction bits.
In addition, the error detection and correction bits having superior ability to detect and correct errors are generally added to the high priority data, and the error detection and correction bits having a comparatively inferior ability to detect and correct errors are added to the low priority data. For this reason, the error detection and correction bits added to the high priority data tend to be longer in its size.
Here,
FIG. 2
shows a transmitter for actually transmitting a frame having such structure. As shown in
FIG. 2
, in the transmitter
1
, a bit stream DH
1
composed of the high priority data is firstly input to a first error correction bit adding circuit
2
, and a bit stream DL
1
composed of the low priority data is input to a second error correction bit adding circuit
3
.
The first error correction bit adding circuit
2
calculates the error detection and correction bits based on the input bit stream DH
1
and adds these error detection and correction bits to the bit stream DH
1
so as to generate a bit stream D
1
which is stored in the aforesaid high priority field. The bit stream D
1
is output to a frame generation circuit
4
at the subsequent stage. In connection, in the first error correction bit adding circuit
2
, the error detection and correction bits having superior ability to detect and correct errors are calculated and added.
While, the second error correction bit adding circuit
3
calculates the error detection and correction bits based on the input bit stream DL
1
and adds these error detection and correction bits to the bit stream DL
1
so as to generate a bit stream D
2
which is stored in the aforesaid low priority field. The bit stream D
2
is output to a frame generation circuit
4
at the subsequent stage. In connection, in the second error correction bit adding circuit
3
, the error detection and correction bits, which have inferior ability to detect and correct errors to the first error correction bit adding circuit
2
, are calculated and added.
As shown in
FIG. 2
, the frame generation circuit
4
adds the bit stream D
2
to the end of the bit stream D
1
to generate transmission data stream D
3
for one frame, which is output to a modulation circuit
5
. The modulation circuit
5
modulates the transmission data stream D
3
to generate transmission symbol stream D
4
, which is output to a transmission circuit
6
. After performing the filtering processing on the transmission symbol stream D
4
, the transmission circuit
6
performs the digital-to-analog conversion processing to generate a transmission signal, and then performs the frequency conversion processing on the transmission signal to generate a transmission signal S
1
. This transmission signal S
1
is transmitted via an antenna
7
, so that the transmitter
1
transmits a combined data of the high priority data and the low priority data.
On the other hand, as shown in
FIG. 3
, in a receiver
10
, the transmission signal S
1
transmitted from the transmitter
1
is received at an antenna
11
, and is input to a reception circuit
12
as a reception signal S
2
. The reception circuit
12
, after performing the filtering processing on the reception signal S
2
, performs the frequency conversion processing on the reception signal S
2
to take out a baseband signal, and performs the analog-to-digital conversion processing on the baseband signal to take out a reception symbol stream D
5
.
The demodulation circuit
13
performs a predetermined demodulating processing on the reception symbol stream D
5
taken out by the reception circuit
12
to decode a reception data stream D
6
(the reception data stream D
6
is not completely equal to the transmission data stream D
3
, and includes data error received through transmission), which is output to a field division circuit
14
. The field division circuit
14
divides the decoded reception data stream D
6
into a bit stream D
7
of the high priority field and a bit stream D
8
of the low priority field, and outputs these bit streams D
7
and D
8
respectively to a first error detection and correction circuit
15
and a second error detection and correction circuit
16
.
The first error detection and correction circuit
15
detects data errors included in the received information bits based on the error detection and correction bits included in the bit stream D
7
and corrects the data errors, so that the transmitted information bits are decoded, and output as a bit stream DH
2
of the high priority data. In the same way, the second error detection and correction circuit
16
detects data errors included in the received information bits based on the error detection and correction bits included in the bit stream D
8
and corrects the data errors, so that the transmitted information bits are decoded, and output as a bit stream DL
2
of the low priority data. By this processing, in the receiver
10
, the high priority data and the low priority data are respectively decoded from the reception signal S
2
.
Transmitting a combination of the high priority data and the low priority data is also performed by the cellular radio communication system such as a portable telephone system. This point will be concretely explained below with an example of a portable telephone system.
Generally, in a portable telephone system, the area where communication service is provided is divided into cells of desired size, and a base station as a fixed radio station is positioned in each cell. A portable telephone device as a mobile radio station radio-communicates with the base station in the cell where the device exists, and so-called cellular radio communication system is constructed.
In such a portable telephone system, when a calling is made by a portable telephone device for example, the call processing is performed by the procedure explained below. The portable telephone device firstly transmits control data composed of preamble data and message data to a base station using a control channel called a random access channel (RACH). The base station monitors the random access channel and detects the existence of the preamble data to detect whether there is a message from the portable telephone device or not. When the preamble data is detected, the base station judges that there is a message from the portable telephone device, detects the following message data, and analyzes the contents of the message data. If the content of the message data is a call request, the base station determines a demesne control channel (DCCH) to be used for communication with the portable telephone dev
Sakoda Kazuyuki
Suzuki Mitsuhiro
Corsaro Nick
Hunter Daniel S.
Maioli Jay H.
Sony Corporation
LandOfFree
Communication method, transmitter, receiver, wherein... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Communication method, transmitter, receiver, wherein..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Communication method, transmitter, receiver, wherein... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2601719