Electrical computers and digital data processing systems: input/ – Input/output data processing – Input/output command process
Reexamination Certificate
2001-12-28
2003-11-04
Gaffin, Jeffrey (Department: 2185)
Electrical computers and digital data processing systems: input/
Input/output data processing
Input/output command process
C712S032000, C712S035000, C711S147000
Reexamination Certificate
active
06643713
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a terminal apparatus for a mobile communication system including a digital cellular portable telephone, or more in particular to a method of realizing a mobile communication baseband system using data processing units such as a programmable microprocessor (hereinafter referred to as “the CPU”) and a digital signal processor (hereinafter referred to as “the DSP”).
BACKGROUND ART
The processes for a mobile communication system relating to the present invention will briefly be described with reference to FIG.
1
.
FIG. 1
shows a user
102
, a communication terminal
101
and a base station
100
. The user
102
accesses the base station
100
using the communication terminal
101
and thus receives various services. The communication with other communication terminals is also performed through the base station
100
. The communication process between the communication terminal and the base station, therefor, constitutes the essential part of the communication.
The communication terminal
101
includes a user interface/system controller
109
having the user interface function and the system control function, a communication protocol processing unit
110
having the communication protocol processing function, a code/decode processing unit
111
having the speech coding/decoding function, the channel coding/decoding function, the modulation/demodulation function, etc., and an AFE/RF circuit section
105
having an analog front end (AFE) and an RF circuit. The communication terminal
101
is connected with a microphone (MIC)
103
and a speaker (SPK)
104
. The base station
100
includes a system controller
112
having the system control function, a communication protocol processing unit
113
having the communication protocol processing function, a channel coding/decoding function, the modulate/demodulate function, etc., and an AFE/RF circuit section
106
having an analog front end (AFE) and an RF circuit.
The communication terminal
101
exchanges information with the base station
100
generally in one of two modes: Audio or the like user data are exchanged, or control data for system management are exchanged.
Audio data are exchanged in the following manner. The audio data input from the microphone (MIC)
103
are converted into digital data and compressed by the speech encoding process in the code/decode processing unit
111
. The compressed audio data have added thereto error correction information by the channel encoding process in the code/decode processing unit
111
, and then modulated by the modulation process in the code/decode processing unit
111
. These processes are performed in a digital area. The modulated digital voice is converted into analog data in the analog front end (AFE) of the AFE/RF circuit section
1605
, and transmitted from an antenna
107
over a radio-frequency wave by the RF circuit of the AFE/RF circuit section
105
. This radio wave is received by an antenna
108
of the base station
100
and temporarily demodulated. This radio wave is modulated again on the frequency (in the case of frequency multiplexing) assigned to the other party of communication, and retransmitted from the base station to the other party in a timing of time slots (in the case of time division multiplexing) assigned to the other party.
Now, the exchange of the control data for system management will be explained. The communication protocol processing unit
110
in the communication terminal
101
and the communication protocol processing unit
113
in the base station
100
exchange data with each other. A virtual logic connection is established between these two functions. This virtual logic connection is realized by a physical connection described below. In the case where the base station
100
issues some instruction to the communication terminal, the process is performed as follows. The instruction data according to a predetermined protocol is encoded for the communication path and modulated in the code/decode processing unit
114
. The resulting data are converted into analog data in the analog front end (AFE) of the AFE/RF circuit section
106
, and transmitted from the RF circuit over a radio wave by way of the antenna
108
. This radio wave is received by the antenna
107
of the communication terminal
101
and converted into baseband digital data through the RF circuit of the RF circuit
105
and the analog front end (AFE). The digital data are further demodulated and decoded for the communication path by the code/decode processing unit
111
and delivered to the communication protocol processing unit
110
.
The two manners in which the communication terminal
101
exchanges data with the base station
100
and the related processes are described above. The processes related to these operations are generally divided into two types. The speech coding/encoding process, the channel coding/decoding process and the modulation/demodulation process are classified as a digital signal process which is suitably realized by an exclusive hardware or a programmable DSP (digital signal processor). The communication protocol process, on the other hand, is so complicated that it is suitably realized by software using a high-level language such as the C language.
In view of these facts, a method has recently been proposed in which the speech coding/encoding process, the channel coding/decoding process and the modulate/demodulate process are performed by a DSP, and the communication protocol process is performed by a CPU (general-purpose microprocessor), among the baseband processes of the mobile communication terminal (“Latest Information on GSM/Systems, Terminals and Services”, Seminar materials, Japan Industrial Technological Center, May 18 to 19, 1965, and “Development Trend of GSM Telephone Terminal Devices”, pp. 118-130, Japan Phillips).
Explanation will be made about an example of a mobile communication terminal including a DSP and a CPU studied by the inventor according to the above-mentioned well-known examples. The example explained below is not an exact replica of any well-known examples. This mobile communication terminal is intended for the GSM (global system for mobile communications) constituting a specification of a digital cellular telephone in Europe. The mobile communication terminal shown in
FIG. 2
includes a DSP chip
223
, a DSP RAM (random access memory)
200
, a DSP ROM (read-only memory)
201
, a CPU chip
227
, a baseband analog front end (AFE)
202
, a RF modem
210
, a power amplifier (PA)
212
, an antenna
213
, a duplexer
214
, a low-noise amplifier (LNA)
215
, a microphone
208
, an amplifier Amp, a speaker
209
, a drive circuit Dri, a frequency synthesizer
216
, a system timing circuit
219
, a voltage controlled system clock
221
, a ¼ frequency dividing circuit
222
, a sounder DA converter
231
, a sounder
230
, a drive circuit Driver, a battery monitor AD converter
232
, battery monitor circuit
233
, a battery
234
, a CPU RAM
239
, a CPU ROM
238
, an LCD (liquid crystal device and a liquid crystal panel)
237
, a SIM (subscriber identity module)
236
and a keyboard
235
. The baseband analog front end (AFE)
202
includes a PA (power amp) D/A converter
203
, an I/Q AD/DA converter
204
, an AGC (auto gain control) D/A converter
205
, an audio AD/DA converter
206
, and an AFC (auto frequency control) D/A converter
207
. The DSP RAM (
200
) and the DSP ROM (
201
) are connected through an external DSP bus
240
to the DSP chip
223
.
The function and operation of this terminal will be explained briefly.
During the audio transmission, the voice input from the microphone
208
is amplified by the amplifier Amp, and converted into digital data by being sampled at the audio A/D converter
206
. The sampling rate is 8 kHz, and the bit accuracy is 13 bits. The data thus digitized is sent to the DSP chip
223
, and after being compressed and encoded for the communication path, delivered to the I/Q D/A converter
204
of the analog front end (AFE)
202
. This signal is modulated
Baji Toru
Hatano Yuji
Nakagawa Tetsuya
Noguchi Koki
Sagesaka Yasuhiro
Antonelli Terry Stout & Kraus LLP
Cao Chun
Gaffin Jeffrey
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