JP2000101675A - Device and method for communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption at the time of use of a single-bit map having small noise by setting a transmission period wherein data transmission is performed and a non-transmission period wherein no data transmission is performed according to the ratio of the data communication quantity to communication capacity, and performing transmission by carrying out bit distribution enabling data of one cycle to be sent in a predistribution transmission period of one cycle. SOLUTION: When the single-bit map using only a bit map A is utilized, bit distribution is obtained which can reduce power consumption and suppress delay caused at the time of rate conversion. The mode wherein power consumption is reduced and a normal mode wherein power consumption is not reduced are switched after the bit allocations of the bit map A and a bit map B are determined. The bit distribution is performed by rate converters 148 and 149. Here, transmit data of one cycle can be transmitted throughout a data transmission period as a period suitable for data transmission in one cycle so as to suppress the delay caused at the time of rate conversion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discrete multitone communication device and a discrete multitone communication method for performing data communication between a plurality of data communication devices via a telephone line by a discrete multitone modulation / demodulation method. is there.

[0002]

2. Description of the Related Art In recent years, as a wired digital communication system, an ADSL (Asymmetric ADSL) which performs high-speed digital communication of several megabits / second using an existing telephone copper wire cable.
DigitalSubscriber Line) communication method, HDSL (hig
h-bit-rate Digital SubscriberLine) communication method, SD
XDSL communication schemes such as SL are receiving attention. The xDSL communication system used for this is DMT (Discrete M
ultiTone). This method uses A
It is standardized in NSI T1.413 and the like. In this digital communication system, particularly, when the xDSL transmission line and the ISDN transmission line of the ISDN communication system of the half-duplex communication system are adjacent to each other, for example, by being bundled by an intermediate line,
It has been pointed out that the xDSL communication via the xDSL transmission line receives interference noise from another line such as an ISDN transmission line, and the speed is reduced.

FIG. 18 shows a central office (CO: Central Offic).
e) The interference noise that the ISDN transmission line 2 gives to the ADSL transmission line 3 because the ISDN transmission line 2 from 1 and the ADSL transmission line 3 that is an xDSL transmission line It shows the situation. here,
AD which is a communication device on the terminal side of the ADSL communication system side
SL terminal side device (ATU-R; ADSL Transceiver U
nit, Remote Terminal end) ISDN
The station equipment (ISDN LT) 7 on the transmission system side is ADS
The interference noise transmitted through the L transmission path 3 is FEXT (F
The terminal apparatus (ISDN NT1) 6 of the ISDN transmission system transmits interference noise transmitted through the ADSL transmission line 3 as NEXT (Near-end cross talk).
cross talk) called noise. These noises, in particular,
The signal is transmitted to the ADSL terminal side device (ATU-R) 4 via the ADSL transmission line 3 by coupling with the ISDN transmission line 2 which becomes an aggregate line or the like on the way and becomes adjacent to the ADSL transmission line 3. In addition, an ADSL station apparatus (ATU-C; ADSL Transceiv) which is an station apparatus of the ADSL communication system side.
er Unit, Central Office end) 5
It is the reverse of the case when viewed from the DSL terminal-side device (ATU-R) 4, and the station-side device (ISDN) on the ISDN transmission system side.
LT) 7 becomes NEXT noise, and the terminal device (ISDN) on the ISDN transmission system side.
The interference noise transmitted by the NT1) 6 becomes FEXT noise.

Here, in the overseas ISDN communication system, the upstream and downstream transmissions are full-duplex transmissions and are performed simultaneously, so that when viewed from the ADSL terminal side device (ATU-R) 4, the ADSL terminal side Terminal device (ISDN NT) on the ISDN transmission system side close to the device (ATU-R) 4
1) NEXT noise generated from 6 is dominant, that is, has a great influence.

For this reason, during the training period of the ADSL modem (not shown) provided in the ADSL terminal unit 4, the characteristics of the NEXT noise component having a large influence are measured, and the transmission of each channel matching the noise characteristics is measured. For example, a time domain equalizer (TEQ; Time dom) that performs a time-domain adaptive equalization process so as to perform a bit map that determines the number of bits and a gain and improve transmission characteristics.
ain Equalizer) and a frequency domain equalizer (FEQ; Freq) that performs adaptive equalization processing in the frequency domain.
uency domain Equalizer)
One set of coefficient tables for NEXT noise is provided for each of TEQ and FEQ.

However, as described above, this does not cause a problem in the case of an overseas digital communication apparatus. However, in Japan and the like, the up-link and down-link data transmissions have been already performed as the existing ISDN communication system, which is a so-called ping-pong system. Since the TCM-ISDN method of half-duplex communication that is switched by division is adopted, if the half-duplex transmission line and another transmission line are adjacent by a collective line or the like, the NEXT noise from the half-duplex transmission line And FEXT noise alternately affect communication terminals connected to other transmission lines adjacent to the half-duplex transmission line.

For this reason, in the Japanese ADSL system, TC
A scheme has been proposed in which a bitmap is switched according to the FEXT section and the NEXT section of M-ISDN interference noise. (■ G.lite: Proposal for draft of Annex of Gl
ite ■, ITU-T, SG-15, Waikiki, Hawaii 29 June-3 July 1
998, Temporary Document WH-047) FIG. 19 shows an outline of a digital communication system using a digital communication device adopting the above method. In FIG. 19, reference numeral 11 denotes a central office (CO) that controls TCM-ISDN communication, ADSL communication, and the like, and 12 denotes a TCM-ISD.
TCM-ISDN transmission line for N communication, 13 is A
ADSL transmission line for performing DSL communication, 14 is ADS
ADSL terminal side device (ATU-R; ADSL Transceiver Unit, Remo) such as a communication modem for performing ADSL communication with another ADSL terminal side device (not shown) via the L transmission line 13
te Terminal end), 15 is an ADSL office unit (ATU-C; ADSL) for controlling ADSL communication in the central office 11
Transceiver Unit, Central Officeend), 16 is TC
A TCM-ISDN terminal device (TCM-I) such as a communication modem for performing TCM-ISDN communication with another TCM-ISDN terminal device (not shown) via the M-ISDN transmission line 12.
SDN NT1), 17 are TCM-IS in the central office 11.
TCM-ISDN station device that controls DN communication (TCM
-ISDN LT), 18 is TCM-ISDN station equipment
(TCM-ISDN LT) 17 and ADSL office equipment (A
TU-C) 15 is a synchronization controller for synchronizing each communication. Note that this synchronous controller 1
8 is a TCM-ISDN station-side device (TCM-ISDN
LT) 17 or ADSL office equipment (ATU-C)
15 may be provided.

As described above, when viewed from the ADSL terminal unit (ATU-R) 14, as shown in FIG. 19, a TCM-ISDN station side device (TCM -ISDN LT) 17 and TCM-ISDN transmission line 12 and ADSL
The interference noise transmitted via the transmission line 13 is referred to as “FEXT
TCM-
ISDN terminal side device (TCM-ISDN NT1) 16
Is a TCM-ISDN transmission line 1 adjacent by a collective line, etc.
2 and the interference noise transmitted via the ADSL transmission line 13 are called "NEXT noise". In contrast, ADS
When viewed from the L station side device (ATU-C) 15, AD
Interference noise transmitted by the station side device (ISDN LT) 17 of the ISDN transmission system, which is a near half-duplex communication device, becomes NEXT noise, which is the reverse of the case seen from the SL terminal side device (ATU-R) 14. I to be a far half duplex communication device
Terminal device of SDN transmission system (ISDN NT1) 16
Is the FEXT noise.

FIG. 20 is a block diagram of A in the digital communication apparatus.
DSL office equipment (ATU-C; ADSL Transceiver U
nit, Central Office end) 15 functionally shows the configuration of a transmission unit such as a communication modem or a transmission-only machine (hereinafter referred to as a transmission system). FIG. 21 functionally shows the configuration of a receiving unit such as a communication modem of the ADSL terminal unit (ATU-R) 14 or a receiving-only device (hereinafter referred to as a receiving system) in the digital communication device.

In FIG. 20, reference numeral 41 denotes a multiplex / sync control (Mux / Sync Control);
Is a cyclic redundancy check (crc), 44,
45 is a scramble forward error correction (S
cram and FEC), 46 is interleave, 47 and 48 are rate converters, 49 is ton ordering, 50 is constellation encoder and gain scaling (constellation encoder).
and gain scalling), 51 is a discrete Fourier transform unit (DF
T) and 52 are input parallel / serial buffers (Input Par
Allel / Serial Buffer 53 is an analog processing / D / A converter (Analog Processing and DAC).

In FIG. 21, reference numeral 141 denotes an analog processing and A / D converter (Analog Processing And).
ADC), 142 is a time domain equalizer (TEC), 1
43 is an input serial / parallel buffer, 144 is a discrete Fourier transform unit (DFT), 145 is a frequency domain equalizer (FEQ), 146 is a constellation encoder and gain scaling (Constellation encoder and
gain scalling), 147 is ton ordering (Tone
ordering), 148, 149 are rate converters (Rate-
Convertor), 150 is Deinterleav
e), 151, 152 are descrambling forward error corrections (Descram and FEC), 153, 15
4 is cyclic redundancy check (crc), 15
5 is multiplex / sync control (Mux / Sync
Control).

Next, the operation will be described. First, the operation of the transmission system of the ADSL station unit (ATU-C) 15 will be described. In FIG. 20, transmission data is multiplexed by multiplex / sync control (Mux / Sync Control), and cyclic redundancy checks 42 and 43 are performed. , An error detection code is added, and the forward error correction 4
At 4 and 45, an FEC code is added and scrambled, and interleaving 46 is applied in some cases. Thereafter, rate conversion processing is performed by the rate converters 47 and 48, ton order processing is performed by the ton ordering 49, constellation data is created by the constellation encoder / gain scaling 50, and discrete Fourier transform is performed by the discrete Fourier transform unit 51. / A
The digital waveform is converted to an analog waveform through a converter, and then a low-pass filter is applied.

On the other hand, an ADSL terminal side device (ATU-R)
The operation of the receiving system 14 will be described. Referring to FIG. 21, an analog processing / A / D converter 141 applies a low-pass filter to a received signal, converts an analog waveform to a digital waveform through an A / D converter, and then converts the analog signal into a time domain equalizer. A time domain adaptive equalization process is performed through (TEQ) 142. Next, the data subjected to the adaptive equalization processing in the time domain is converted from serial data to parallel data via the input serial / parallel buffer 143, and the discrete Fourier transform unit (DFT) 1
The discrete Fourier transform is performed at 44, and an adaptive equalization process in the frequency domain is performed by a frequency domain equalizer (FEQ) 145. The constellation data is reproduced by the constellation encoder / gain scaling 146, converted into serial data by the tongue ordering 147, rate-converted by the rate converters 148 and 149, and subjected to FEC and descrambling by the descrambling / forward error correction 151. Process,
In some cases, de-interleaving 150 is applied to the descrambling forward error correction 152 to obtain F
Perform EC and descramble processing, and then perform cyclic redundancy checks 153 and 154 to perform multiplex / sync control (Mux / Sync Control).
l) Reproduce the data by 155.

At this time, in the central office (CO) 11, the synchronization controller 18 controls the TCM-ISDN station-side device (TCM-ISDN).
ISDN LT) 17 and ADSL office equipment (ATU-
C) Since the transmission timing is synchronized with 15), the ADSL terminal unit (ATU-R) 14
The generation timing of the T noise and the FEXT noise can be recognized.

That is, the ADSL terminal side device (ATU-
R) 14 synchronizes the TCM-ISDN communication and the ADSL communication with the TCM-I whose timing is known in advance.
During a predetermined time during which data is traveling on the SDN transmission line 12, while it is determined that NEXT noise occurs in the reception data and the reception signal received via the ADSL transmission line 13, the timing is similarly known in advance. TCM-IS
During a predetermined time during which data is falling on the DN transmission line 12, FE is added to the reception data and the like received through the ADSL transmission line 13.
It can be recognized that XT noise occurs.

In the Japanese ADSL system, a bitmap A and a bitmap B corresponding to each of the FEXT section and the NEXT section are allocated as shown in FIG.
In the rate converters 148 and 149, the bit allocation is increased in the FEXT section where the noise amount is small,
Bit allocation is reduced in the NEXT section having a large amount of noise. Thereby, the transmission rate can be increased as compared with the case where the bit allocation is determined only in the NEXT section up to now.

FIG. 23 shows how data that is transmitted at a uniform rate (64 kbps in the following calculation example) is allocated to bitmap A and bitmap B during transmission. First, fixed bits are stored in data sent at a uniform rate in symbol units. It is converted into bits for bitmap A and bitmap B by a rate converter. However, the ISDN cycle is 2.5m
s, the interval between transmission symbols is 246 μs,
It does not become an integral multiple. Therefore, as shown in FIG. 24, 34 periods (= 345 symbols, 85 ms) are defined as one unit (hyperframe), and the FE in this hyperframe is
Only a portion where a symbol can be completely included in the XT section is set as a bitmap A, and the other portion is set as a bitmap B (SS and ISS are synchronization signals in the figure). Each DMT
Whether a symbol belongs to bitmap A or bitmap B is determined by the following equation. (In the following equation, the DMT symbol number is Ndmt.)

In the case of transmission from ATU-C to ATU-R: S = 272 × Ndmt mod 2760 if {(S + 271 <a) or (S> a + b)} then [bitmap A symbol] if { (S + 271> = a) and (S <= a + b)} then [bitmap B symbol] where a = 1243, b = 1461

In the case of transmission from ATU-R to ATU-C: S = 272 × Ndmt mod 2760 if {(S> a) and (S + 271 <a + b)} then [Bitmap A symbol] if { (S <= a) or (S + 271> = a + b)} then [bitmap B symbol] where a = 1315, b = 1293

The following is an example of calculation for obtaining bit assignment in the case of a single bitmap in which only bitmap A is used for data assignment. -Number of bits of one DMT symbol (before rate conversion) = (transmission rate) x (transmission time) / (total number of symbols (excluding ISS (Inverse synch symbol) and SS (Synch symbol))) = 64 kbps x 85 ms / 340 = 16 Bit Number of bits of bitmap A = (transmission rate) × (transmission time) / (number of symbols of bitmap A (excluding ISS (Inverse synch symbol) and SS (Side A Synch symbol))) = 64 kbps × 85 ms / 126 = 43.175 Therefore, the bit map A is set to 44 bits. Also, since it is a single bitmap (only bitmap A is used), bitmap B = 0 bits.

When the bit distribution is changed by the rate converter as described above, data is accumulated to some extent in the transmission-side or reception-side rate converter and then output, so that a delay time in the rate converter occurs. Furthermore, the bitmap A of the hyperframe
Bit is allocated as much as possible to the portion of the bit map A in some cases, data may be allocated to a portion of the bitmap A in a later period in some cases, and further delay time is required for the data. Will occur.

The data rate of an ADSL modem (not shown) provided in the ADSL terminal device 14 is determined from the bit distribution converted from the S / N ratio measured during the training period. On the other hand, when the actual communication rate is low, it is not necessary to use all the data frames. Therefore, as a conventional method for reducing power consumption, a transmission mode as shown in FIG. 25 has been proposed in ITU-T. For example, when the data rate that can be transmitted on the ADSL transmission line is 64 kbps, but the actual communication data is only 32 kbps, in the normal mode, data of 32 kbps was transmitted using all data frames. , 1/2 mode, four frames of 32 kbps data are packed and transmitted in two frames, and the next two frames are not transmitted. Thereby, power consumption can be reduced to half. Similarly, FIG.
6, 1/4 mode, 1/17 mode, etc. have been proposed as shown in FIG.

[0023]

In the single bitmap using only the bitmap A described above, ADSL is used.
When data is transmitted from the optical line terminal, the hatched portion in FIG. 24 becomes the bitmap A, and when data is transmitted from the ADSL terminal side device, the hatched portion in FIG. Become. Also, when the ADSL station-side device is performing a transmitting operation, the ADSL terminal-side device is performing a receiving operation. Conversely, when the ADSL terminal-side device is performing a transmitting operation, the ADSL station-side device is performing. The side device performs a receiving operation. For example, in the first cycle (the cycle of the symbols of symbol numbers 0 to 9), the ADS
The L station side device transmits symbols of symbol numbers 0 to 3,
When the ADSL terminal device transmits symbols with symbol numbers 5 to 8, the ADSL station device transmits the symbol numbers 0 to 8.
For symbol 3, transmission operation is performed and symbol numbers 5 to 5 are used.
The reception operation is performed with the symbol 8. Therefore, only the symbols of symbol number 4 and symbol number 9 do not operate in the first cycle. The same applies to the ADSL terminal side device. For this reason, in a single bitmap using only bitmap A, most symbols are transmitted and received in each cycle, and there is a problem that power cannot be reduced. In addition, the above-described conventional power reduction mode, for example, 1 /
In 2 mode, data for 4 frames is packed into 2 frames, and the next 2 frames are not transmitted.
As shown in FIG. 24, there is a problem that communication cannot be performed in consideration of transmission in a FEXT section where the influence of noise is small.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a communication apparatus and a communication system capable of reducing power consumption even in the case of communication using a single bitmap which is less affected by noise. The aim is to provide a method.

[0025]

According to the present invention, there is provided a communication apparatus for performing data communication, wherein bits are allocated so that data is transmitted during a data transmission period of a predetermined period which is a period suitable for data transmission. In the data transmission period, a transmission period in which data transmission is performed and a non-transmission period in which data transmission is not performed are set in accordance with a ratio of a data communication amount to a communication capacity in the data transmission period. The bit allocation is performed so that the minute data can be transmitted.

A communication apparatus according to the present invention is characterized in that, in a communication apparatus performing data communication, when bits are allocated so as to transmit data during a data transmission period of a predetermined period which is a period suitable for data transmission, In the data transmission period, a transmission period in which data transmission is performed and a non-transmission period in which data transmission is not performed are set in accordance with a ratio of a data communication amount to a communication capacity, and one cycle of data is transmitted in the transmission period of one cycle. The transmitted data is received by allocating bits so that the data can be distributed, and among the received data, all data for one cycle is reproduced based on the data allocated to the transmission period for one cycle.

A communication apparatus according to the present invention is characterized in that, in a communication apparatus for performing data communication, when performing bit allocation so as to transmit data during a data transmission period that is a period suitable for data transmission in a predetermined period, In the data transmission period, a transmission period in which data transmission is performed and a non-transmission period in which data transmission is not performed are set in accordance with a ratio of data communication amount to communication capacity, and data for a predetermined period is transmitted in the transmission period for a predetermined period. Bit allocation is performed to enable transmission.

A communication apparatus according to the present invention is characterized in that, in a communication apparatus performing data communication, when bits are allocated so as to transmit data during a data transmission period that is a period suitable for data transmission in a predetermined period, In the data transmission period, a transmission period in which data transmission is performed and a non-transmission period in which data transmission is not performed are set in accordance with a ratio of a data communication amount to a communication capacity. Receiving the transmitted data by performing bit allocation so that the data can be transmitted, and reproducing all data for a predetermined cycle based on the data allocated to the transmission period for a predetermined cycle among the received data. It is.

[0029] The communication method according to the present invention is characterized in that, in a communication apparatus for performing data communication, when a bit is allocated so as to transmit data during a data transmission period of a predetermined period which is a period suitable for data transmission, In the data transmission period, a transmission period in which data transmission is performed and a non-transmission period in which data transmission is not performed are set in accordance with a ratio of a data communication amount to a communication capacity, and one cycle of data can be transmitted in one transmission period. In this way, bits are allocated and transmitted.

According to the communication method of the present invention, in a communication apparatus for performing data communication, when bits are allocated so as to transmit data during a data transmission period of a predetermined period which is a period suitable for data transmission, In the data transmission period, a transmission period in which data transmission is performed and a non-transmission period in which data transmission is not performed are set in accordance with a ratio of a data communication amount to a communication capacity, and one cycle of data is transmitted in the transmission period of one cycle. The transmitted data is received by allocating bits so that the data can be distributed, and among the received data, all data for one cycle is reproduced based on the data allocated to the transmission period for one cycle.

[0031] The communication method according to the present invention is characterized in that, in a communication apparatus for performing data communication, when performing bit allocation so as to transmit data during a data transmission period which is a period suitable for data transmission in a predetermined cycle, In the data transmission period, a transmission period in which data transmission is performed and a non-transmission period in which data transmission is not performed are set in accordance with a ratio of data communication amount to communication capacity, and data for a predetermined period is transmitted in the transmission period for a predetermined period. Bit allocation is performed to enable transmission.

A communication method according to the present invention is characterized in that, in a communication apparatus for performing data communication, when bits are allocated so as to transmit data in a data transmission period of a predetermined period which is a period suitable for data transmission, In the data transmission period, a transmission period in which data transmission is performed and a non-transmission period in which data transmission is not performed are set in accordance with a ratio of a data communication amount to a communication capacity. Receiving the transmitted data by performing bit allocation so that the data can be transmitted, and reproducing all data for a predetermined cycle based on the data allocated to the transmission period for a predetermined cycle among the received data. It is.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, an embodiment of the present invention will be described. In the present embodiment, bit allocation that can reduce power consumption in the case of a single bitmap using only bitmap A and that can suppress delay that occurs during rate conversion is shown. The following is an example of calculation for obtaining. Switching between the mode for reducing power consumption and the mode for not reducing (normal) is performed after the bit allocation of the bitmap A and the bitmap B is determined. Therefore, in the present embodiment, bitmap A = 44 bits and bitmap B when the transmission rate obtained by the conventional technique is 64 kbps.
A calculation example using a bit assignment of = 0 bits will be described. The bit distribution is performed by the rate converters 148 and 149 in FIG.

As described above, S measured during the training period
A calculation example in the case where the transmittable data rate of the ADSL transmission line determined based on the / N ratio is 64 kbps but the actual communication data is only 32 kbps (1/2 mode) is shown below. FIG. 1 shows a diagram of bit allocation. Here, in order to suppress a delay occurring at the time of rate conversion, all transmission data for one cycle is transmitted in a data transmission period that is a period suitable for data transmission within one period (for example, corresponding to the above-described FEXT section). Allocate bits as possible. In addition, a dummy bit is inserted into a portion where the transmission data is not allocated within the data transmission period, and the transmission is performed.

The specifications in such a bit allocation are as follows (in the present embodiment, the transmittable data rate of the ADSL transmission line determined based on the S / N ratio measured during the training period is 64 kbps. However, this shows an example of calculating the bit allocation when the actual communication data is only 32 kbps). -Number of bits of 1 DMT symbol (before rate conversion) = (transmission rate) x (transmission time) / (total number of symbols (excluding ISS (Inverse synch symbol) and SS (Synch symbol))) = 32 kbps x 85 ms / 340 = 8 Bits Therefore, the number of bits of ten DMT symbols, which is transmission data for one cycle, is 80 bits. Bitmap A
Since the bit assignment of one symbol is 44 bits, two symbols of the bitmap A are required to transmit one cycle of transmission data (80 bits). Dummy bits of the second bitmap A in each cycle = (number of bits of bitmap A) × (2 symbols) − (transmission data for one cycle) = 44 × 2-80 = 8 bits

FIG. 2 (A) shows the allocation of the transmission symbols to be transmitted with the number of bits obtained in the hyperframe.
The transmission method from the DSL station-side device) and the transmission method from the ADSL terminal-side device) are shown in FIG. In the figure, the symbols circled are transmission symbols. Here, since the symbols that are not used as transmission symbols in both the ADSL station side device and the ADSL terminal side device are unused symbols, the power consumption reduction rate is as follows. -Reduction rate of power consumption (in 1/2 mode) = (total number of symbols-(number of transmission symbols used in ADSL station side device + number of transmission symbols used in ADSL terminal side device)) / (total number of symbols) = (345− (70 + 70)) / 345 = 59.4% Further, the ratio of the transmission rate according to the present embodiment to the transmission rate when all the bitmaps A are transmitted is as follows. Transmission rate ratio (for 1/2 mode) = (number of transmission symbols) / (number of symbols of bitmap A) = 70/128 = 54.7% That is, the transmission rate when all bitmaps A are transmitted (64kbps) for 54.7% (about 35kbp)
s) is secured as the transmission rate of the actual data transmission, and the data (32 kbps) actually communicated has a sufficient transmission rate.

Next, the transmittable data rate of the ADSL transmission line determined based on the S / N ratio measured during the training period is 64 kbps, but the actual communication data is 1 kbps.
A calculation example in the case of only 6 kbps (1/4 mode) is shown below. FIG. 4 shows a diagram of bit allocation. As in the case described above, in order to suppress the delay that occurs at the time of rate conversion, data transmission is performed within a period suitable for data transmission within one period (for example, corresponding to the above-described FEXT section). Allocate bits so that they can all be transmitted in time. In addition, a dummy bit is inserted into a portion where the transmission data is not allocated within the data transmission period, and the transmission is performed.

The specifications in such a bit allocation are as follows (in the present embodiment, the transmittable data rate of the ADSL transmission line determined based on the S / N ratio measured during the training period is 64 kbps. However, a calculation example of the bit allocation in the case where the actual communication data is only 16 kbps is shown). -Number of bits of one DMT symbol (before rate conversion) = (transmission rate) x (transmission time) / (total number of symbols (excluding ISS (Inverse synch symbol) and SS (Synch symbol))) = 16 kbps x 85 ms / 340 = 4 Bits Therefore, the number of bits of 10 DMT symbols, which is transmission data for one cycle, is 40 bits. Bitmap A
Since the bit allocation of one symbol is 44 bits, one symbol of the bitmap A is required to transmit transmission data (40 bits) for one cycle. Dummy bits of the first bitmap A in each cycle = (number of bits of bitmap A)-(transmission data for one cycle) = 44-40 = 4 bits

FIG. 5 (A) shows the allocation of the transmission symbols to be transmitted with the number of bits determined in the hyperframe.
FIG. 6 (a transmission method from the ADSL terminal side device) and FIG. 6 (a transmission method from the ADSL terminal side device). In the figure, the symbols circled are transmission symbols. Here, since the symbols that are not used as transmission symbols in both the ADSL station side device and the ADSL terminal side device are unused symbols, the power consumption reduction rate is as follows. -Reduction rate of power consumption (for 1/4 mode) = (total number of symbols-(number of transmission symbols used by ADSL station side device + number of transmission symbols used by ADSL terminal side device)) / (total number of symbols) = (345− (36 + 36)) / 345 = 79.1% Further, the ratio of the transmission rate according to the present embodiment to the transmission rate when all the bitmaps A are transmitted is as follows. Transmission rate ratio (for 1/4 mode) = (number of transmission symbols) / (number of symbols of bitmap A) = 36/128 = 28.1% That is, the transmission rate when all bitmaps A are transmitted 28.1% of (64 kbps) (about 18 kbps)
Is secured as a transmission rate for actual data transmission, and data (16 kbps) to be actually communicated has a sufficient transmission rate.

FIG. 7 summarizes the above results with respect to the power consumption reduction rate and the transmission rate ratio. As shown in FIG. 7, according to the present invention, the power consumption can be reduced as compared with the conventional method.
It can be seen that a transmission rate of 50% or more and a transmission rate of 1/4 = 25% or more in the 1/4 mode are secured. Therefore, the communication device according to the present invention can reduce power consumption in the case of a single bitmap, and can suppress a delay that occurs at the time of rate conversion.

In this embodiment, the case where the transmittable data rate of the ADSL transmission line determined based on the S / N ratio measured during the training period is 64 kbps, but the same applies to other transmission rates. The effect can be obtained.

In the above description, the functions shown using the functional block diagram may be realized by H / W or S / W.

Embodiment 2 Hereinafter, an embodiment of the present invention will be described. In the above-described embodiment, the bit allocation has been described in which the power consumption can be reduced in the case of the single bitmap using only the bitmap A, and the delay that occurs during the rate conversion can be suppressed. That is, data for one cycle is always assigned to the corresponding portion of the bit map A for one cycle so that data is not delayed. In the present embodiment, bitmap A
In the case of a single bitmap using only a single bitmap, power consumption can be reduced and bit allocation with good transmission efficiency is shown. That is, data of all the hyperframes is allocated to all of the bitmap A without waste (the number of dummy bits is minimized), so that the transmission efficiency is improved. As in the above embodiment, switching between the mode for reducing power consumption and the (normal) mode in which reduction is not performed is as follows.
This is performed after the bit allocation of the bitmap A and the bitmap B is determined. In the present embodiment, the bitmap A = 44 bits and the bitmap B = 0 bits when the transmission rate obtained by the conventional technique is 64 kbps. The following is an example of calculation using the bit allocation of FIG. In addition, the bit allocation is performed according to the rate converters 148, 1 in FIG.
Perform at 49.

First, the transmittable data rate of the ADSL transmission line determined based on the S / N ratio measured during the training period is 64 kbps, but the actual communication data is 3 kbps.
Since it is only 2 kbps, a calculation example in the case of transmitting in the 1/2 mode is shown below. FIG. 8 shows a diagram of bit allocation. Number of symbols in bitmap A (ISS (Inverse synchs
ymbol) and SS (excluding Synch symbol) are 126. In order to prevent the occurrence of dummy bits as much as possible,
63 symbols, which is の of the symbols, are used as transmission symbols.

The specifications in such a bit allocation are as follows (in the present embodiment, the data rate of the ADSL transmission line determined based on the S / N ratio measured during the training period is 64 kbps, An example of calculation of bit allocation in a case where actual communication data is only 32 kbps is shown). -Total number of bits transmitted in one hyperframe (before rate conversion) = (transmission rate) x (transmission time) = 32 kbps x 85 ms = 2720 bits-Dummy bits = (bit number of bitmap A) x (number of transmission symbols) ) − (Total number of bits transmitted in one hyperframe frame) = 44 × 63−2720 = 52 bits (= 44 bits + 8 bits) Therefore, 8 bits and 6 bits of the transmission symbol of the 62nd symbol
Dummy bits are inserted into all of the transmission symbols of the third symbol (transmission data is distributed in 44 bits for the 1st to 61st symbols of the transmission symbol). FIG. 9 (a transmission method from the ADSL station side device) shows an example of allocation of transmission symbols to be transmitted with the number of bits determined above in a hyperframe.
FIG. 10 (a transmission method from the ADSL terminal side device) is shown (the allocation examples in FIGS. 9 and 10 show an example in which the delay time is allocated so as not to be extremely long). In the figure, the symbols circled are transmission symbols. Here, since the symbols that are not used as transmission symbols in both the ADSL station side device and the ADSL terminal side device are unused symbols, the power consumption reduction rate is as follows. -Reduction rate of power consumption (in 1/2 mode) = (total number of symbols-(number of transmission symbols used in ADSL station side device + number of transmission symbols used in ADSL terminal side device)) / (total number of symbols) = (345− (65 + 65)) / 345 = 62.3% Further, the ratio of the transmission rate according to the present embodiment to the transmission rate when all the bitmaps A are transmitted is as follows. -Transmission rate ratio (for 1/2 mode) = (number of transmitted symbols (including ISS and SS)) / (number of symbols of bitmap A (including ISS and SS)) = 65/128 = 50.8% , 50.8% of the transmission rate (64 kbps) when all bitmaps A are transmitted (about 32.5 kbps).
s) is secured as the transmission rate of the actual data transmission, and the data (32 kbps) actually communicated has a sufficient transmission rate.

Next, the data rate of the ADSL transmission line determined based on the S / N ratio measured during the training period is 64 kbps, but the actual communication data is 16 kbps.
A calculation example in the case where there is only s (the mode is set to １ ／) is shown below. FIG. 11 shows a diagram of bit allocation. Number of symbols in bitmap A (ISS (Inverse synch symbol), SS (Sy
(excluding nch symbol)) is 126. Therefore, 32 symbols, which are 1/4 of 126 symbols, are used as transmission symbols so that dummy bits are not generated as much as possible.

The specifications in such a bit allocation are as follows (in the present embodiment, the data rate of the ADSL transmission line determined based on the S / N ratio measured during the training period is 64 kbps, An example of calculation of bit allocation in a case where communication data of the embodiment is only 16 kbps is shown). -Total number of bits transmitted in one hyperframe (before rate conversion) = (transmission rate) x (transmission time) = 16 kbps x 85 ms = 1360 bits-Dummy bits = (bit number of bitmap A) x (number of transmission symbols) ) − (Total number of bits transmitted in one hyperframe 1 frame) = 44 × 32−1360 = 48 bits (= 44 bits + 4 bits) Therefore, 8 bits and 3 bits of the 31st symbol transmission symbol
Dummy bits are inserted into all the transmission symbols of the second symbol (transmission data is distributed 44 bits at each of the 1st to 30th symbols of the transmission symbol). In addition, examples of allocation of a transmission symbol to be transmitted with the number of bits determined in the hyperframe in a hyperframe are shown in FIG. 12 (a transmission method from an ADSL station apparatus) and FIG. 13 (a transmission method from an ADSL terminal apparatus) ( The assignment examples in FIGS. 12 and 13 show an example in which the assignment is performed such that the delay time is not extremely long.) In the figure, the symbols circled are transmission symbols. Here, since the symbols that are not used as transmission symbols in both the ADSL station side device and the ADSL terminal side device are unused symbols, the power consumption reduction rate is as follows. -Reduction rate of power consumption (for 1/4 mode) = (total number of symbols-(number of transmission symbols used by ADSL station side device + number of transmission symbols used by ADSL terminal side device)) / (total number of symbols) = (345− (34 + 34)) / 345 = 80.3% The ratio of the transmission rate according to the present embodiment to the transmission rate when transmitting all the bitmaps A is as follows. -Transmission rate ratio (for 1/4 mode) = (number of transmission symbols (including ISS and SS)) / (number of symbols of bitmap A (including ISS and SS)) = 34/128 = 26.6% , 26.6% (approximately 17 kbps) of the transmission rate (64 kbps) for transmitting all the bitmaps A is secured as the data rate of the actual data transmission, which is sufficient for the data (16 kbps) actually communicated. There is a transmission rate.

Further, the S / N measured during the training period
The data rate of the ADSL transmission line determined based on the ratio is 64 kbps, but the actual communication data is 64/1.
An example of calculation in the case where the speed is only 7 (= 3.8) kbps (1/17 mode) is shown below. FIG. 14 shows a diagram of bit allocation. Number of symbols in bitmap A (ISS (Invers
e synch symbol) and SS (synch symbol) are 126. Therefore, eight symbols, which are 1/17 of 126 symbols, are set as transmission symbols so that dummy bits are not generated as much as possible. The specifications in such a bit allocation are as follows (in the present embodiment, S measured during the training period)
The data rate of the ADSL transmission line determined based on the / N ratio is 64 kbps, but the actual communication data is 64 kbps.
An example of calculation of bit allocation in the case where there is only / 17 kbps is shown). -Total number of bits transmitted in one hyperframe (before rate conversion) = (transmission rate) x (transmission time) = (64/17 kbps) x 85 ms = 320 bits-Dummy bits = (bit number of bitmap A) x (Number of transmission symbols) − (total number of bits transmitted in one frame of hyperframe) = 44 × 8−320 = 32 bits Accordingly, dummy bits are inserted into 32 bits of the eighth transmission symbol (1 to (Transmission data is allocated 44 bits each for the seventh symbol). 15 (transmission method from ADSL station-side device) and FIG. 16 (transmission method from ADSL terminal-side device) show examples of allocation of transmission symbols transmitted with the number of bits determined above in a hyperframe. The assignment examples in FIGS. 15 and 16 show an example in which the assignment is performed such that the delay time is not extremely long.) In the figure, the symbols circled are transmission symbols. Here, since the symbols that are not used as transmission symbols in both the ADSL station side device and the ADSL terminal side device are unused symbols, the power consumption reduction rate is as follows. -Reduction rate of power consumption (in the case of 1/17 mode) = (total number of symbols-(number of transmission symbols used by ADSL station side device + number of transmission symbols used by ADSL terminal side device)) / (total number of symbols) = (345− (10 + 10)) / 345 = 94.2% The ratio of the transmission rate according to the present embodiment to the transmission rate when all the bitmaps A are transmitted is as follows. -Transmission rate ratio (for 1/17 mode) = (number of transmitted symbols (including ISS and SS)) / (number of symbols of bitmap A (including ISS and SS)) = 10/128 = 7.8% , 7.8% (approximately 5 kbps) of the transmission rate (64 kbps) in the case of transmitting all the bitmaps A is secured as the transmission rate of the actual data transmission, and the data (3.8 kbps) to be actually communicated is Has a sufficient transmission rate.

FIG. 17 summarizes the above results with respect to the power consumption reduction rate and the transmission rate ratio.
As shown in FIG. 17, according to the present invention, the power consumption can be reduced as compared with the conventional method.
It can be seen that a transmission rate of ２ = 50% or more, a transmission rate of １ ／ = 25% or more in the ４ mode, and a transmission rate of 1/17 = 5.9% or more in the 1/17 mode. Therefore, the communication measure according to the present invention can reduce power consumption in the case of a single bitmap, and can transmit data efficiently.

Although the present embodiment has been described for the case where the data rate of the ADSL transmission line determined based on the S / N ratio measured during the training period is 64 kbps, the same effect can be obtained with other transmission rates. Obtainable.

In the above description, the functions shown using the functional block diagram may be realized by H / W or S / W.

[0052]

As described above, in the communication apparatus for performing data communication, when performing bit allocation so as to transmit data during a data transmission period which is a period suitable for data transmission in a predetermined period, In the data transmission period, a transmission period in which data transmission is performed and a non-transmission period in which data transmission is not performed are set in accordance with a ratio of a data communication amount to a communication capacity, and one cycle of data can be transmitted in one transmission period. By allocating bits and transmitting as described above, power consumption can be reduced in the case of a single bitmap using only bitmap A, and a delay generated during rate conversion can be suppressed.

Further, in a communication apparatus for performing data communication, when bits are allocated so as to transmit data during a data transmission period of a predetermined period which is a period suitable for data transmission, the data transmission is performed during the data transmission period. A transmission period in which transmission is performed and a non-transmission period in which data transmission is not performed are set according to a ratio of data traffic to communication capacity,
Receiving the transmitted data by performing bit allocation so that data for one cycle can be transmitted in the transmission period for one cycle;
The power consumption is reduced in the case of a single bitmap using only bitmap A by reproducing all data for one cycle based on the data allocated to the transmission period for one cycle among the received data. Can be
In addition, it is possible to suppress a delay occurring at the time of rate conversion.

In a communication apparatus for performing data communication, when bits are allocated so as to transmit data during a data transmission period which is a period suitable for data transmission in a predetermined period, the data transmission is performed during the data transmission period. And a non-transmission period during which data transmission is not performed is set according to a ratio of a data communication amount to a communication capacity, and bit allocation is performed so that data of a predetermined period can be transmitted in the transmission period of a predetermined period. , The power consumption can be reduced in the case of a single bitmap using only the bitmap A, and the data can be transmitted efficiently.

Further, in a communication apparatus for performing data communication, when bits are allocated so as to transmit data during a data transmission period of a predetermined period which is a period suitable for data transmission, the data transmission is performed during the data transmission period. A transmission period in which transmission is performed and a non-transmission period in which data transmission is not performed are set according to a ratio of data traffic to communication capacity,
Received transmitted data by performing bit allocation so that data of a predetermined period can be transmitted in the transmission period of a predetermined period, and of the received data, the data is allocated to the transmission period of a predetermined period. By reproducing all data for a predetermined period based on data, power consumption can be reduced in the case of a single bitmap using only bitmap A, and data can be transmitted efficiently.

Further, in a communication apparatus for performing data communication, when performing bit allocation so as to transmit data during a data transmission period of a predetermined period which is a period suitable for data transmission, data transmission is performed during the data transmission period. And a non-transmission period during which data transmission is not performed are set in accordance with a ratio of a data communication amount to a communication capacity, and bits are allocated so that data of one period can be transmitted in the transmission period of one period. By transmitting, the power consumption can be reduced in the case of a single bitmap using only bitmap A, and the delay that occurs during rate conversion can be suppressed.

Further, in a communication apparatus for performing data communication, when bits are allocated so as to transmit data during a data transmission period of a predetermined period which is a period suitable for data transmission, the data transmission is performed during the data transmission period. A transmission period in which transmission is performed and a non-transmission period in which data transmission is not performed are set according to a ratio of data traffic to communication capacity,
Receiving the transmitted data by performing bit allocation so that data for one cycle can be transmitted in the transmission period for one cycle;
The power consumption is reduced in the case of a single bitmap using only bitmap A by reproducing all data for one cycle based on the data allocated to the transmission period for one cycle among the received data. Can be
In addition, it is possible to suppress a delay occurring at the time of rate conversion.

Further, in a communication apparatus for performing data communication, when bits are allocated so as to transmit data during a data transmission period of a predetermined period which is a period suitable for data transmission, data transmission is performed during the data transmission period. And a non-transmission period during which data transmission is not performed is set according to a ratio of a data communication amount to a communication capacity, and bit allocation is performed so that data of a predetermined period can be transmitted in the transmission period of a predetermined period. , The power consumption can be reduced in the case of a single bitmap using only the bitmap A, and the data can be transmitted efficiently.

In a communication apparatus for performing data communication, when bits are allocated so as to transmit data during a data transmission period of a predetermined period, which is a period suitable for data transmission, the data transmission is performed during the data transmission period. A transmission period in which transmission is performed and a non-transmission period in which data transmission is not performed are set according to a ratio of data traffic to communication capacity,
Received transmitted data by performing bit allocation so that data of a predetermined period can be transmitted in the transmission period of a predetermined period, and of the received data, the data is allocated to the transmission period of a predetermined period. By reproducing all data for a predetermined period based on data, power consumption can be reduced in the case of a single bitmap using only bitmap A, and data can be transmitted efficiently.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing bit allocation according to the present invention.

FIG. 2 is an explanatory diagram showing allocation of transmission symbols in a hyperframe according to the present invention;

FIG. 3 is an explanatory diagram showing allocation of transmission symbols in a hyperframe according to the present invention.

FIG. 4 is an explanatory diagram showing bit allocation according to the present invention.

FIG. 5 is an explanatory diagram showing allocation of transmission symbols in a hyperframe according to the present invention.

FIG. 6 is an explanatory diagram showing allocation of transmission symbols in a hyperframe according to the present invention.

FIG. 7 is an explanatory diagram showing the result of comparing the power consumption reduction rate and the transmission rate ratio between the present invention and the conventional method.

FIG. 8 is an explanatory diagram showing bit allocation according to the present invention.

FIG. 9 is an explanatory diagram showing allocation of transmission symbols in a hyperframe according to the present invention.

FIG. 10 is an explanatory diagram showing allocation of transmission symbols in a hyperframe according to the present invention.

FIG. 11 is an explanatory diagram showing bit allocation according to the present invention.

FIG. 12 is an explanatory diagram showing allocation of transmission symbols in a hyperframe according to the present invention.

FIG. 13 is an explanatory diagram showing allocation of transmission symbols in a hyperframe according to the present invention.

FIG. 14 is an explanatory diagram showing bit allocation according to the present invention.

FIG. 15 is an explanatory diagram showing allocation of transmission symbols in a hyperframe according to the present invention.

FIG. 16 is an explanatory diagram showing allocation of transmission symbols in a hyperframe according to the present invention.

FIG. 17 is an explanatory diagram showing the result of comparing the power consumption reduction rate and the transmission rate ratio between the present invention and the conventional method.

FIG. 18 is an explanatory diagram showing a state of interference noise between transmission paths.

FIG. 19 is an explanatory diagram showing a state of interference noise between transmission paths.

FIG. 20 is a functional configuration diagram showing a transmission function of the ADSL station apparatus;

FIG. 21 is a functional configuration diagram showing a receiving function of the ADSL terminal side device;

FIG. 22 is an explanatory diagram showing correspondence between a FEXT period and a NEXT period and a bit map;

FIG. 23 is an explanatory diagram showing conventional bitmap allocation.

FIG. 24 is an explanatory diagram showing the structure of a hyperframe.

FIG. 25 is an explanatory diagram showing a conventional mode for reducing power consumption.

FIG. 26 is an explanatory diagram showing a conventional mode for reducing power consumption.

FIG. 27 is an explanatory diagram showing a conventional mode for reducing power consumption.

FIG. 28 is an explanatory diagram showing the structure of a hyperframe.

[Explanation of symbols]

41 Multiplex / Sync Control 42, 43 Cyclic Redundancy Check 44, 45 Scramble Forward Error Correction 46 Interleave 47, 48 Rate Converter 49 Ton Ordering 50 Constellation Encoder / Gain Scaling 51 Discrete Fourier Transform 52 Input Parallel / Serial Buffer 53 Analog Processing / D / A Converter 141 Analog Processing / A / D Converter 142 Time Domain Equalizer 143 Input Serial / Parallel Buffer 144 Discrete Fourier Transform Unit 145 Frequency Domain Equalizer 146 Constellation Encoder Gain Scaling 147 Ton Ordering 148, 149 Rate Converter 150 deinterry Probe 151, 152 Descramble Forward Error Correction 153, 154 Cyclic Redundancy Check 155 Multiplex / Sync Control

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04M 11/00 302 H04M 11/00 302 H04Q 11/04 H04Q 11/04 T

Claims (8)

[Claims] In a communication apparatus for performing data communication, when performing bit allocation to transmit data during a data transmission period that is a period suitable for data transmission in a predetermined period, data transmission is performed during the data transmission period. And a non-transmission period during which data transmission is not performed are set in accordance with a ratio of a data communication amount to a communication capacity, and bits are allocated so that data of one period can be transmitted in the transmission period of one period. Communication device to send. 2. In a communication apparatus for performing data communication, when bits are allocated so as to transmit data in a data transmission period that is a period suitable for data transmission in a predetermined period, the data is transmitted in the data transmission period. A transmission period during which data is transmitted and a non-transmission period during which data is not transmitted are set in accordance with a ratio of data communication amount to communication capacity, and bit allocation is performed so that data for one cycle can be transmitted in the transmission period for one cycle. A communication device that receives transmitted data and reproduces all data for one cycle based on the data allocated to the transmission period for one cycle among the received data. 3. In a communication apparatus for performing data communication, when performing bit allocation so as to transmit data during a data transmission period that is a period suitable for data transmission in a predetermined period, data transmission is performed during the data transmission period. And a non-transmission period during which data transmission is not performed is set according to a ratio of a data communication amount to a communication capacity, and bit allocation is performed so that data of a predetermined period can be transmitted in the transmission period of a predetermined period. A communication device that performs and transmits. 4. In a communication apparatus for performing data communication, when bits are allocated so as to transmit data in a data transmission period that is a period suitable for data transmission in a predetermined period, the data is transmitted in the data transmission period. A transmission period in which transmission is performed and a non-transmission period in which data transmission is not performed are set according to a ratio of a data communication amount to a communication capacity, and bits are set so that data of a predetermined period can be transmitted in the transmission period of a predetermined period. A communication device which receives data transmitted after being distributed and reproduces all data of a predetermined cycle based on data distributed in the transmission period of a predetermined cycle among the received data. 5. In a communication apparatus for performing data communication, when performing bit allocation so as to transmit data during a data transmission period that is a period suitable for data transmission in a predetermined period, data transmission is performed during the data transmission period. And a non-transmission period during which data transmission is not performed are set in accordance with a ratio of a data communication amount to a communication capacity, and bits are allocated so that data of one period can be transmitted in the transmission period of one period. The communication method to send. 6. In a communication device for performing data communication, when bits are allocated so as to transmit data during a data transmission period of a predetermined period that is a period suitable for data transmission, the data is transmitted during the data transmission period. A transmission period during which data is transmitted and a non-transmission period during which data is not transmitted are set in accordance with a ratio of data communication amount to communication capacity, and bit allocation is performed so that data for one cycle can be transmitted in the transmission period for one cycle. A communication method for receiving transmitted data and reproducing all data for one cycle based on data allocated to the transmission period for one cycle among the received data. 7. In a communication apparatus for performing data communication, when performing bit allocation so as to transmit data during a data transmission period that is a period suitable for data transmission in a predetermined period, data transmission is performed during the data transmission period. And a non-transmission period during which data transmission is not performed is set according to a ratio of a data communication amount to a communication capacity, and bit allocation is performed so that data of a predetermined period can be transmitted in the transmission period of a predetermined period. Communication method to send. 8. In a communication apparatus for performing data communication, when bits are allocated so as to transmit data in a data transmission period of a predetermined period, which is a period suitable for data transmission, the data is transmitted in the data transmission period. A transmission period in which transmission is performed and a non-transmission period in which data transmission is not performed are set according to a ratio of a data communication amount to a communication capacity, and bits are set so that data of a predetermined period can be transmitted in the transmission period of a predetermined period. A communication method for receiving data transmitted after being distributed and reproducing all data for a predetermined period based on data distributed for a predetermined period in the transmission period among the received data.