JP2000307545A - Communication equipment and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold consistency with other countries and to efficiently transmit data by transmitting data by dividing a system for transmitting up/down data by frequency division and a system for transmitting up/down, data by time division with the threshold by means of setting a prescribed frequency as the threshold. SOLUTION: The distribution of bits inputted to a rate converter 47 is processed in a 100 symbol unit with one symbol as 25 μs when one period of TCM-ISDN of 400 Hz is set to be a basic unit. In bit distribution after rate conversion by a TDD system, 45 symbols are down-transmitted and next 45 symbols are up-transmitted by leaving five symbols and next down transmission is executed by leaving five symbols, In the data frequency, allocation of tone ordering 49, data in the TDD system is allocated to the frequency whose tone number is not more than 25 and data of an FDD system to the frequency whose tone number is not less than 26. Thus, data in the FDD system and the TDD system are transmitted in a range which does not exceed the maximum value of the number of bits per one symbol with the S/N of a training period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device and a communication method for performing data communication between a plurality of data communication devices by, for example, a discrete multi-tone modulation / demodulation method.

[0002]

2. Description of the Related Art In recent years, a VDSL (Very-high-bi
The t-rate Digital Subscriber Line) communication system is drawing attention. The main modulation and demodulation methods used for this are DM
There is a T (Discrete MultiTone) modulation / demodulation method.

[0003] When trying to adopt this VDSL communication system, it is necessary to consider the influence of interference noise with the existing ISDN transmission line. FIG. 22 shows interference between the ISDN transmission line 2 and the VDSL transmission line 3 due to the fact that the ISDN transmission line 2 from the central office (CO) 1 and the VDSL transmission line 3 are bundled together on an intermediate line. It shows the appearance of noise.

[0004] Here, a VDSL terminal side device (VTU-R) 4 which is a terminal side communication device of the VDSL communication system side.
From the point of view, the station apparatus (I
Interference noise transmitted by the SDN LT 7 through the VDSL transmission line 3 is called FEXT (Far-end cross talk) noise, and a terminal device (ISDNN) on the ISDN transmission system side.
The interference noise transmitted by the T1) 6 through the VDSL transmission line 3 is called NEXT (Near-end cross talk) noise.
These noises, in particular, form an aggregate
The data is transmitted to the VDSL terminal side device (VTU-R) 4 via the VDSL transmission line 3 by coupling with the SLDN 3 and the adjacent ISDN transmission line 2. It should be noted that a VDSL station apparatus (VTU) which is a station apparatus of the VDSL communication system side.
-C) From the viewpoint of 5, the VDSL terminal side device (VT
The interference noise transmitted from the ISDN transmission system-side station-side device (ISDN LT) 7 becomes NEXT noise, and the ISDN transmission system-side terminal device (ISDN NT1) 6 Is the FEXT noise.

[0005] During a training period of a VDSL modem (not shown) provided in the VDSL terminal side device 4,
By measuring the characteristic of the NEXT noise component having a large effect,
For example, a time domain equalizer (TEQ; Time domain equalizer (TEQ)) that performs a time domain adaptive equalization process so as to perform a bit map that determines the number of transmission bits and a gain of each channel according to the noise characteristics and improve transmission characteristics.
Equalizer) and a frequency domain equalizer (FEQ; Frequenc) that performs adaptive equalization processing in the frequency domain.
y domain Equalizer) is converged and determined, and TE
One set of NEXT noise coefficient tables is provided for each of Q and FEQ.

FIG. 23 is an explanatory diagram showing an outline of an FDD (Frequency Division Duplex) system in which uplink (US: UpStream) and downlink (DS: DownStream) data are transmitted by frequency division. For example, US xDSL communication In many systems, this FDD system is adopted. FDD
XDSL communication systems that use the
Even if both signals overlap in time, the above-mentioned interference noise can be avoided because the frequencies are different.

FIG. 24 shows a TD in which uplink (US) and downlink (DS) data are transmitted in a so-called ping-pong manner by time division.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing an outline of a D (Time Division Duplex) system. In a Japanese ISDN communication system, a TCM-ISDN system using the TDD system is adopted.

[0008]

However, a VDSL transmission line adopting the FDD scheme as shown in FIG. 23 and a TCM-channel adopting the TDD scheme as shown in FIG.
When the ISDN transmission line is adjacent to the transmission line, interference noise due to the same frequency is generated in a portion where signals of both (VDSL and TCM-ISDN) overlap in time, and transmission efficiency is extremely deteriorated. there were. Also, TCM-
If the TDD system is adopted in the VDSL communication system in order to avoid interference noise due to the ISDN communication system,
Consistency with the United States and other foreign countries that adopt the FDD system will be lost.

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a communication device and a communication method capable of efficiently transmitting data while maintaining consistency with foreign countries. .

[0010]

A communication apparatus according to the present invention uses a predetermined frequency as a threshold value to transmit uplink and downlink data by frequency division, and transmits uplink and downlink data by time division. And data transmission by dividing the data by the threshold value.

A communication apparatus according to the present invention uses a predetermined frequency as a threshold value to transmit uplink and downlink data by frequency division and a method to transmit uplink and downlink data by frequency division and time division. Is transmitted by dividing the data by the threshold value.

[0012] A communication apparatus according to the present invention includes a method of transmitting uplink and downlink data by frequency division using a predetermined frequency as a threshold, a method of transmitting uplink and downlink data by time division, and a method of transmitting uplink and downlink data by time division. Data is transmitted by dividing the downlink data by frequency division and time division by the threshold.

[0013] In the above method, data is transmitted by preferentially using a method of transmitting uplink and downlink data by frequency division.

When multiplexing and transmitting fast data which requires a small delay time and interleaved data which requires a small data error, the fast data is transmitted preferentially. It is.

In the communication method according to the present invention, data is transmitted by dividing a method of transmitting uplink and downlink data by frequency division and a method of transmitting uplink and downlink data by time division.

A communication method according to the present invention is a method for transmitting data by dividing a method of transmitting uplink and downlink data by frequency division and a method of transmitting uplink and downlink data by frequency division and time division. It is.

[0017] The communication method according to the present invention includes a method of transmitting uplink and downlink data by frequency division, a method of transmitting uplink and downlink data by time division, and a method of transmitting uplink and downlink data by frequency division and time division. Data is transmitted separately from the method of transmission by division.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 shows a VDSL station-side device (VTU-C; VDSL Transceiver) according to the present invention.
iverUnit, Central Office end) and VDSL terminal side device (VTU-R; VDSL Transceiver Unit, Remote)
FIG. 2 is a functional configuration diagram functionally showing a configuration of a transmission unit such as a communication modem at a terminal end or a transmission-only machine (hereinafter referred to as a transmission system).

In FIG. 1, reference numeral 41 denotes a multiplex /
Sync control (Mux / Sync Control), 42, 43 are cyclic redundancy check (crc), 44, 4
5 is a scramble forward error correction (Scr
am and FEC), 46 is interleaved, 47 and 48 are rate converters, 49 is tone ordering, 50 is a constellation encoder and gain scaling (Constellation encoder).
and gain scalling), 51 is an inverse discrete Fourier transform unit (ID
FT) and 52 are input parallel / serial buffers (Input Pa
Rallel / SerialBuffer) and 53 are analog processing and D / A converters (Analog Processing and DAC).

Next, the overall operation when data is transmitted from the VDSL station unit (VTU-C) to the VDSL terminal unit (VTU-R) will be described. First, the operation of the transmission system of the VDSL station apparatus (VTU-C) will be described.
, Transmission data is multiplexed by multiplex / sync control (Mux / Sync Control), error detection codes are added by cyclic redundancy checks 42, 43, and forward error correction 44,
At 45, an FEC code is added and scrambled, and an interleave 46 is applied in some cases. Thereafter, rate conversion processing is performed by rate converters 47 and 48, tone ordering processing is performed by tone ordering 49, and constellation data is created by constellation encoder / gain scaling 50.
Inverse discrete Fourier transform is performed by an inverse discrete Fourier transform unit 51,
The input parallel / serial buffer 52 converts the parallel data into serial data, converts the digital waveform into an analog waveform through a D / A converter, and then applies a low-pass filter.

On the other hand, FIG. 2 shows a VDSL station side device (VTU-
FIG. 2C is a functional configuration diagram functionally showing the configuration of a receiving unit such as a communication modem of a VDSL terminal device (VTU-R) or a receiving-only device (hereinafter referred to as a receiving system).

In FIG. 2, reference numeral 141 denotes an analog processing and A / D converter.
C), 142 are time domain equalizers (TEC), 14
3 is an input serial / parallel buffer, 144 is a discrete Fourier transform unit (DFT), 145 is a frequency domain equalizer (FEQ), and 146 is a constellation encoder and gain scaling (Constellation encoder and g).
ain scalling), 147 is tone 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 VDSL terminal side device (VTU-R)
The operation of the receiving system 14 will be described. Referring to FIG. 2, an analog processing / A / D converter 141 applies a low-pass filter to a received signal, converts an analog waveform into a digital waveform through an A / D converter, and then converts the analog waveform into a digital signal. 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 an input serial / parallel buffer 143, and is converted to a discrete Fourier transform unit (DFT) 14.
4 and a frequency domain equalizer (FEQ) 145 performs an adaptive equalization process in the frequency domain. The constellation data is reproduced by the constellation encoder / gain scaling 146, converted into serial data by the tone 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. VDSL terminal equipment (VTU-R) to VDSL office equipment (VTU-C)
The same applies to the operation in the case of transmitting data to.

Here, the interference noise due to the TCM-ISDN communication system usually occurs largely at 1.1 MHz or less. Therefore, for example, data is transmitted by the TDD method in a frequency band that is susceptible to interference noise by the TCM-ISDN communication system, and data is transmitted by the FDD method in a frequency band higher than that.

FIG. 3 is an explanatory diagram showing an outline of a communication method according to the present invention. The example of FIG. 3 shows that data is transmitted by the TDD method below 1.1 MHz and data is transmitted by the FDD method above 1.1 MHz. The threshold (1.1 MHz) is determined, for example, during the above-described training period.

FIG. 4 is an explanatory diagram showing the assignment of data to tones in the communication method according to the present invention. According to the example of FIG. 3, the data of the TDD system is transmitted from tone numbers # 1 to # 2.
5 and the data of the FDD system is tone number # 26.
The above shows the case of allocation.

Next, a detailed operation will be described. In the present embodiment, data is transmitted from the VDSL central unit (VTU-C) to the VDSL terminal unit (VTU-R) using only one of the fast data buffer path and the interleaved buffer path. Will be described. In this embodiment, the case where only the fast data buffer path is used is described, but only the interleaved data buffer path may be used. In the communication device according to the present invention, since the rate converter 47 and the tone ordering 49 in the configuration of the transmission system perform characteristic operations, the operation of this portion will be described in detail.

(1) When t> t_fdd_max FIG. 5 is an explanatory diagram showing detailed operations of the rate converter 47 and the tone ordering 49 when t> t_fdd_max. In the present embodiment, for example, as shown in FIG.
Assuming that one cycle of TCM-ISDN communication of 00 Hz is a basic unit, one symbol is processed in 25 μs and 100 symbols are processed. In this case, in the TDD system, as shown in FIG.
Downlink (DS) data transmission is performed with 5 symbols, uplink (US) data transmission is performed with the next 45 symbols after 5 symbols, and next downlink (DS) data transmission is performed with 5 symbols. Then, as shown in (c) of FIG. 5 showing the assignment of data to frequencies in tone ordering, T
The data of the DD system is allocated to the frequency of tone number # 25 or lower, and the data of the FDD system is allocated to the frequency of tone number # 26 or higher.

As shown in FIG. 5B, the FD determined based on the S / N ratio measured during the training period described above.
T_fdd_max is the number of bits per symbol that can be transmitted in the D system (tone number # 26 or more), and TD determined based on the S / N ratio measured during the training period described above.
Assuming that the number of bits per symbol that can be transmitted in the D system (tone number # 25 or less) is t_tdd_max, FIG.
As shown in (a), the maximum value of the number of bits t per symbol of the net data to be transmitted before rate conversion is determined from these values, and data transmission is performed within a range not exceeding the maximum value of t. Done.

FIG. 5 shows a case where t> t_fdd_max, and a calculation example of each value will be described below. In the example of FIG. 5A, the number of bits t per symbol of the transmitted net data before rate conversion is t = 24 bits. In FIG. 5B, the number of bits per symbol t_fdd_max that can be transmitted in the FDD scheme (tone number # 26 or more) determined based on the S / N ratio measured during the training period is t_fdd_max = 16. Bit. Therefore, in (b) of FIG. 5, the FDD system after rate conversion (tone number # 26 or higher)
Assuming that the number of bits per symbol to be transmitted is t_fdd, t_fdd = t_fdd_max = 16 bits.
Of the 24 bits, t_fdd = 16 bits are processed at a uniform rate. Then, the remaining net data is
Transmission is performed by the DD system. As shown in FIG. 5B, TD
In the D system, downlink (DS) data transmission is performed with 45 symbols. Therefore, assuming that the number of bits per symbol to be transmitted in the TDD system (tone number # 25 or less) after rate conversion is t_tdd, t_tdd = roundup ( (Tt−fdd) × 100/45) = roundup ((24−16) × 100/45) = roundup (8 × 100/45) = 18 bits In this case, dummy bits are generated. If the number of dummy bits is dummy_tdd, dummy_tdd = 45 × t_tdd− (tt−fdd) × 100 = 45 × 18− (24−16) × 100 = 10 bits.

Then, as shown in FIG. 5C, in tone ordering 49, t_tdd = 18 bits of data are assigned to tone numbers # 1 to # 25 in the TDD system, and t_fdd = 16 bits of data are assigned to the tone number. #
Assigned to 26 or more and transmitted by FDD system.

That is, data is transmitted as much as possible by the FDD system with a small delay time, and the remaining data is transmitted by the TDD system.

(2) When t ≦ t_fdd_max FIG. 6 is an explanatory diagram showing detailed operations of the rate converter 47 and the tone ordering 49 when t ≦ t_fdd_max. The operation of FIG. 6A is the same as that of FIG. 5A except that only the FDD system is used in FIG. 6B and only the FDD system data is used as the tone number in FIG. 6C. The difference from FIG. 5 is that frequencies are assigned to frequencies # 26 and higher.

FIG. 6 shows a case where t ≦ t_fdd_max, and an example of calculation of each value will be described below. In the example of FIG. 6A, the bit number t per symbol of the net data to be transmitted before the rate conversion is t = 24 bits. In FIG. 6B, t_fdd_max represents the number of bits per symbol that can be transmitted in the FDD scheme (tone number # 26 or more) determined based on the S / N ratio measured during the training period, and t_fdd_max = 32 bits. Therefore, t ≦ t_fdd_max, so that t_fdd = t = 24 bits, and as shown in FIG.
7, the net data t = 24 bits are all processed at a uniform rate.

As shown in FIG. 6C, in tone ordering 49, t_fdd = 24-bit data is allocated to tone number # 26 or higher and transmitted by the FDD system, and data is stored in tone number # 25 or lower. Do not assign.

That is, when all data can be transmitted by the FDD system with a small delay time, transmission is performed using only the FDD system and not using the TDD system.

In the tone ordering 147 and the rate converter 148 in the configuration of the receiving system, the operation opposite to the above operation is performed. Also, the VDSL terminal side device (VT
The same operation is performed when data (US) is transmitted from the U-R) to the VDSL station-side device (VTU-C).

As described above, according to the first embodiment, a method of transmitting uplink and downlink data by frequency division using a predetermined frequency as a threshold, and a method of transmitting uplink and downlink data by time division By transmitting the data by dividing the data by the threshold value, the interference noise by the TCM-ISDN communication system is avoided, and the transmission by the TDD method is reduced as much as possible. , And can be transmitted efficiently.

The threshold value of the frequency that separates the FDD system from the TDD system is not limited to 1.1 MHz, and other values may be used according to the state of interference, noise, transmission path, transmission speed, and the like. Is also good. In addition, for example, two thresholds are provided, and three thresholds of a high frequency band, a middle frequency band, and a low frequency band are set.
A plurality of thresholds may be provided, for example, by dividing data into two frequency bands, transmitting data using the TDD method in the high frequency band, transmitting data using the FDD method in the middle frequency band, and transmitting data using the TDD method in the low frequency band. .

Although the upper limit of the frequency used by the FDD system is 17.6 MHz in FIG. 3, another value may be used in accordance with the increase or decrease of the bandwidth used by the FDD.

In this embodiment, the number t of bits per symbol of the transmitted net data before rate conversion is 24 bits, and the S / N measured during the training period is 24 bits.
FDD method (tone number # 26)
The number of bits per symbol t_fd that can be transmitted
Although the case where d_max is 16 bits and 32 bits has been described, similar effects can be obtained by using other values.

In FIG. 5, dummy bits are inserted at the last part of the 45 symbols after the rate conversion. However, dummy bits are inserted at the forefront part, the middle part of the 45 symbols, or evenly in each symbol. Well, not limited to this.

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

Embodiment 2 In the present embodiment, a description will be given of an embodiment in which the influence on VDSL communication devices in other countries is further considered than in the above embodiment. If the VDSL transmission line as shown in FIG. 3 of the above embodiment and the VDSL transmission lines of other countries as shown in FIG.
Below Hz, there is a part where both signals overlap,
Interference noise due to the same frequency occurs.

FIG. 7 is an explanatory view showing an outline of a communication method according to the present invention in which both signals are transmitted so as not to overlap in order not to generate the interference noise. FIG.
In the example of the above, data is transmitted by the TDD system below 1.1 MHz, only the upstream (US) is transmitted below 0.5 MHz, and only the downstream (DS) is transmitted below 0.5 MHz and below 1.1 MHz. Is shown. Note that these thresholds (1.1 MHz and 0.5 MHz) are determined, for example, during the training period described above.

FIG. 8 is an explanatory diagram showing the assignment of data to tones in the communication method according to the present invention. In accordance with the example of FIG. 7, upstream (US) data of the TDD system has tone numbers # 1 to # 11. To the downlink (DD
The data of S) is assigned to tone numbers # 12 to # 25, and the FDD data is assigned to tone numbers # 26 and higher.

(1) When t> t_fdd_max and Downlink (DS) Data is Assigned FIG. 9 is an explanatory diagram showing the operation of the rate converter 47 and tone ordering 49 in this case. As in the above-described embodiment, only one of the fast data buffer path and the interleaved buffer path is used, and the VDSL station apparatus (VTU-C) transmits the data to the VDSL terminal apparatus (VTU-R). The case of transmitting data is described. In this embodiment, the case where only the fast data buffer path is used is described, but only the interleaved data buffer path may be used.

The operation is the same as that shown in FIG. 5 of the above embodiment except that the tones allocated in uplink (US) and downlink (DS) data transmission are different as shown in FIG. 9 (c). Here, FIG. 9 shows a case where t> t_fdd_max and downlink (DS) data is allocated. In the tone ordering 49, DS data of t_tdd = 18 bits in (b) of FIG. 9 includes tone numbers # 12 to #, as shown in (c) of FIG.
25 (DS) and transmitted by the TDD system.

In the tone ordering 147 and the rate converter 148 in the configuration of the receiving system, the operation opposite to the above operation is performed.

(2) When t> t_fdd_max and when Uplink (US) Data is Assigned FIG. 10 shows a VDSL terminal side device (VTU) in this case.
-R) to the VDSL station apparatus (VTU-C) (U
FIG. 11 is an explanatory diagram showing operations of the rate converter 47 and the tone ordering 49 when transmitting the data of S), and is the same as FIG. 5 of the above embodiment except that the tones allocated in FIG. 10C are different. .

Here, FIG. 10 shows that t> t_fdd_max
This shows a case where uplink (US) data is allocated. In the tone ordering 49, FIG.
(B), t_tdd = 18-bit US data has tone numbers # 1 to # 1 as shown in FIG.
# 11 (US) and transmitted by the TDD method.

(3) When t ≦ t_fdd_max is satisfied and downlink (DS) data is allocated. FIG. 11 shows a rate converter 47 and tone ordering 49 when t ≦ t_fdd_max is allocated and downlink (DS) data is allocated. FIG. 12 is the same as FIG. 6 of the above embodiment except that the tone to be assigned is different in FIG. 11 (c). As shown in FIG. 11B, in the rate converter 47, all the net data t = 24 bits in FIG. 11A are processed at a uniform rate, and in the tone ordering 49, t_fdd = 24 in FIG. The bit data is stored in the tone number # 2 as shown in FIG.
No. 6 or more and transmitted by FDD method, tone number # 2
No data is assigned to 5 or less.

(4) When t ≦ t_fdd_max and Uplink (US) Data Are Assigned FIG. 12 shows the rate converter 47 and tone ordering 49 when t ≦ t_fdd_max and uplink (US) data is assigned. 13 is the same as FIG. 6 of the above embodiment, except that the tone to be allocated is different in (c) of FIG. As shown in FIG. 12B, the rate converter 47 processes all the net data t = 24 bits in FIG. 12A at a uniform rate, and in the tone ordering 49, t_fdd = 24 in FIG. The bit data is stored in the tone number # 2 as shown in FIG.
No. 6 or more and transmitted by FDD method, tone number # 2
No data is assigned to 5 or less.

As described above, according to the second embodiment, a method of transmitting uplink and downlink data by frequency division using a predetermined frequency as a threshold value, a method of transmitting uplink and downlink data by frequency division, By transmitting data by dividing the time-division transmission method by the threshold value, the TCM-I
Since interference noise due to the SDN communication system can be avoided and transmission is performed in the TDD system and the FDD system, the efficiency is reduced as compared with the above embodiment.
Consistency with foreign countries using the DD system can be completely maintained.

Note that the FDD system and the FDD system and the TD
The threshold value of the frequency that separates the transmission method from the transmission method using the D method and the value of the frequency that switches between the uplink and the downlink when the transmission is performed by the FDD method and the TDD method are 1.1 MHz or 0.1 MHz.
The value is not limited to 5 MHz, and another value may be used according to the state of interference (or noise, transmission path, transmission speed, and the like).
Also, for example, by providing two thresholds, a high frequency band,
It is divided into three frequency bands, a middle frequency band and a low frequency band. The high frequency band is the FDD system and the TDD system, the middle band is the FDD system, the low band is the FDD system and the TDD system. Such as transmitting data with
A plurality of thresholds may be provided.

As shown in FIG. 13, for example, two thresholds are provided to divide the frequency band into three frequency bands of a high frequency band, a middle frequency band, and a low frequency band. The three systems may be divided by a plurality of thresholds, such as transmitting data in the middle frequency band by the FDD system and the TDD system and transmitting data in the low band frequency band by the TDD system. The operation in each band is the same as in the above embodiment.

Although the upper limit of the frequency used by the FDD system is 17.6 MHz in FIG. 7, another value may be used in accordance with the increase or decrease of the bandwidth used by the FDD.

In the present embodiment, the bit number t per symbol of the transmitted net data before rate conversion is 24 bits, and the S / N measured during the training period is 24 bits.
FDD method (tone number # 26)
The number of bits per symbol t_fd that can be transmitted
Although the case where d_max is 16 bits and 32 bits has been described, similar effects can be obtained by using other values.

Although dummy bits are inserted at the end of the 45 symbols after the rate conversion in FIGS. 9 and 10, the dummy bits are inserted so as to be uniform at the foremost part, intermediate part, or each symbol of the 45 symbols. It may be inserted, but is not limited to this.

Further, the functions shown using the functional configuration diagram in the above description may be realized by H / W or S / W.

Embodiment 3 In the above embodiment, a case has been described where only one of the fast data buffer path and the interleaved buffer path is used to transmit data, but in the present embodiment, for example, the delay time may be small. Two paths are used, such as transmitting voice data as required on a fast data buffer path and transmitting internet data on an interleaved buffer path that requires less data errors. VDSL station side equipment (VTU-
A description will be given of a case in which data is transmitted from C) to the VDSL terminal device (VTU-R). In this embodiment, as in the above-described embodiment, an example in which data is transmitted by the TDD scheme below 1.1 MHz and data is transmitted by the FDD scheme above 1.1 MHz as shown in FIG. I do. Further, as in the above embodiment, this threshold value (1.1 MHz) is determined, for example, during the training period described above. In the communication device according to the present invention, since the rate converter 47 and the tone ordering 49 in the configuration of the transmission system perform characteristic operations, the operation of this portion will be described in detail.

(1) When t _f > t_fdd_max FIG. 14 is an explanatory diagram showing detailed operations of the rate converter 47 and the tone ordering 49 when t _f > t_fdd_max. In the present embodiment, for example, as shown in FIG. 14A showing the bit allocation before rate conversion, when one cycle of 400 Hz TCM-ISDN communication is used as a basic unit, processing is performed in 100 symbol units with one symbol being 25 μs. I do. In this case, in the TDD system, as shown in FIG. 14B showing bit allocation after rate conversion, downlink (DS) data transmission is performed with 45 symbols, and after 5 symbols, uplink (US) is performed with the next 45 symbols. )
And the next downlink (D
The data transmission of S) is performed. Then, as shown in (c) of FIG. 14 showing the allocation of data to frequencies in tone ordering, the data of the TDD system has a tone number # 2.
5 or less, and FDD data is assigned to a frequency of tone number # 26 or more.

As shown in FIG. 14B, F is determined based on the S / N ratio measured during the training period.
The number of bits per symbol that can be transmitted by the DD system (tone number # 26 or more) is t_fdd_max, and T is determined based on the S / N ratio measured during the training period described above.
Assuming that the number of bits per symbol that can be transmitted in the DD system (tone number # 25 or less) is t_tdd_max, as shown in FIG. 14A, one symbol of net data to be transmitted before rate conversion is calculated from these values as shown in FIG. The maximum value of the number of bits per hit t is determined, and data transmission is performed within a range not exceeding the maximum value of t. As shown in FIG. 14A, the number of bits t per symbol of the transmitted net data before the rate conversion is equal to the number of bits t _i per symbol of the interleaved data to be transmitted before the rate conversion. And the number of bits t per symbol of the fast data to be transmitted before the rate conversion.
_{and f} .

Here, FIG. 14 shows that t _f > t_fdd_ma
The case of x is shown, and a calculation example of each value will be described below. In the example of FIG. 14A, the number of bits t _f per symbol of the fast data to be transmitted before the rate conversion is t _f = 16 bits. In FIG. 14B, the number of bits t_fdd_max per symbol that can be transmitted by the FDD scheme (tone number # 26 or more) determined based on the S / N ratio measured during the training period is t_fdd_max = 12. Bit.

Here, for example, fast data that requires a short delay time in the fast data buffer path is transmitted first by the FDD system with a short delay time. Therefore, in FIG. 14B, assuming that the number of bits per symbol of fast data to be transmitted in the FDD scheme (tone number # 26 or more) after rate conversion is t _{f —} fdd, t _{f —} fdd = t_fdd_max = a 12-bit, treated with uniform rates for t _f _fdd = 12 bits of the fast data t _f = 16 bits in the rate converter 47.

Then, the remaining fast data and the
-Transmitted data is transmitted by the TDD method. In FIG.
As shown in (b), in the TDD scheme, 45 symbols are used.
Downstream (DS) data transmission, so rate conversion
Should be transmitted using the TDD system (tone number # 25 or less) after
The number of bits per symbol of the fast data is t _f
_Tdd, t_f_Tdd = roundup ((t_f-T_f—Fdd) × 100/45) = roundup ((16−12) × 100/45) = 9 bits. In this case, a dummy bit is generated.
Dummy the number of me bits_f_Tdd, dummy_f_Tdd = 45 × t_f_Tdd- (t_f-T_f_Fdd) × 100 = 45 × 9− (16−12) × 100 = 5 bits

In the example of FIG. 14A, the number of bits t _i per symbol of the interleaved data to be transmitted before rate conversion is t _i = 8 bits. Therefore, when the number of bits per symbol of the interleaved data to be transmitted in the TDD mode after rate conversion in (b) of FIG. 14 (tone number # 25 below) and t _i _tdd, Becomes In this case, the dummy bit is generated, when the number of the dummy bits and dummy _i _tdd, the _{dummy i _tdd = 45 × t i} _tdd-t i × 100 = 45 × 18-8 × 100 = 10 bits.

Then, as shown in FIG.
In the ordering 49, t _f_Tdd = 9 bits
Data and t_i_Tdd = 18-bit data is
Assigned to the session numbers # 1 to # 25 in the TDD scheme,_f_
fdd = 12-bit data is greater than tone number # 26
The transmission is performed by the allocation FDD method.

That is, fast data that requires a short delay time is transmitted as much as possible by the FDD system with a small delay time, and the remaining fast data and interleaved data are transmitted by the TDD system.

[0070] (2) t _f ≦ t_fdd_max and t
(= T _i + t _f )> t_fdd_max FIG. 15 is an explanatory diagram showing detailed operations of the rate converter 47 and the tone ordering 49 in this case. The operation of FIG. 15A is the same as that of FIG.
In FIG. 15B, for fast data, F
Only the DD system is used, and both the FDD system and the TDD system are used for the interleaved data. In FIG. 15C, a part of the fast data and the interleaved data is converted to the tone number # 26 by the FDD system. It differs from FIG. 14 in that it is allocated to the above-mentioned frequencies and the remaining interleaved data is allocated to a frequency of tone number # 25 or lower by the TDD method.

Here, FIG. 15 shows that t _f ≦ t_fdd_ma
x and t (= t _i + t _f )> t_fdd_max, and a calculation example of each value will be described below. In the example of FIG. 15A, the bit number t _f per symbol of the fast data to be transmitted before the rate conversion is t _f = 16 bits. In addition, the FDD method determined based on the S / N ratio measured during the training period (tone number # 26 or higher)
Number of bits per symbol t_fdd_m that can be transmitted by
ax is t_fdd_max = 18 bits. Here, for example, fast data that requires a short delay time of the fast data buffer path is transmitted first by the FDD scheme with a short delay time. For this reason, in (b) of FIG. 15, the FDD system after the rate conversion (tone number # 2)
6 or more) is the number of bits per symbol to be transmitted in t _f
When _Fdd, and t _f _fdd = t _f = 16 bits, all treated at a uniform rate fast data t _f = 16 bits in the rate converter 47.

The interleaved data is transmitted by the FDD system at a uniform rate as much as possible.
The rest is transmitted by the TDD method. In the example of FIG. 15A, the interleaved data to be transmitted before the rate conversion is performed.
The number of bits t _i per symbol of data is t _i = 8 bits. Therefore, in (b) of FIG. 15, if the number of bits per symbol of the interleaved data to be transmitted in the FDD scheme (tone number # 26 or more) after rate conversion is t _{i —} fdd, In the rate converter 47, t _i _fdd = 2 bits of the interleaved data t _i = 8 bits are processed at a uniform rate.

Then, the remaining interleaved data is transmitted by the TDD method. As shown in FIG. 15 (b), in the TDD system, downlink (DS) data transmission is performed in 45 symbols, so that the interleaved data to be transmitted in the TDD system after the rate conversion (tone number # 25 or less) is performed. Is the number of bits per symbol of t _i _tdd
When, a _{t i _tdd = roundup ((t} i -t i _fdd) × 100/45) = roundup ((8-2) × 100/45) = 14 bits. In this case, the dummy bit is generated, when the number of the dummy bits and _{dummy i _tdd, dummy i _tdd =} 45 × t i _tdd- (t i -t i _fdd) × 100 = 45 × 14- (8-2 ) × 100 = 30 bits.

Then, as shown in FIG.
In the ordering 49, t _i_Tdd = 14 vi
TD data is allocated to tone numbers # 1 to # 25.
In the D method, t_f_Fdd = 16-bit data and t_i_
fdd = 2-bit data is allocated to tone number # 26 or higher.
The transmission is performed by the allocation FDD method.

That is, fast data and a part of interleaved data that require a short delay time are transmitted by the FDD system with a small delay time, and the remaining interleaved data are transmitted by the TDD system. I do.

(3) t (= t _i + t _f ) ≦ t_fdd_m
ax FIG. 16 is an explanatory diagram showing detailed operations of the rate converter 47 and the tone ordering 49 in this case. The operation of FIG. 16A is the same as that of FIG.
In FIG. 16B, only the FDD system is used, and FIG.
14 is different from FIG. 14 in that only data of the FDD system is assigned to a frequency of tone number # 26 or higher in (c) of FIG.

Here, FIG. 16 shows that t (= t _i + t _f ) ≦ t_
The case of fdd_max is shown, and a calculation example of each value will be described below. In the example of FIG. 16A, the number of bits t per symbol of the net data to be transmitted before the rate conversion is t = 24 bits. In FIG. 16B, t_fdd_max represents the number of bits per symbol that can be transmitted in the FDD scheme (tone number # 26 or more) determined based on the S / N ratio measured during the training period, and t_fdd_max = 32 bits. Therefore, t (= t _i + t _f ) ≦ t_fdd_
and t _f _fdd = t _f = 16-bit t _i _fdd = t _i = 8 bits for the max, as shown in (b) of FIG. 16, the fast data t _f = 16 bits and interleaved in the rate converters 47 Process all data t _i = 8 bits at a uniform rate.

Then, as shown in FIG.
In the ordering 49, t _f= 16-bit file
Last data and t_i= 8-bit interleaved
-Data is allocated to tone number # 26 or higher FDD system
And data is allocated to tone numbers # 25 and below
Absent.

That is, when all data can be transmitted by the FDD system with a small delay time, transmission is performed using only the FDD system and not using the TDD system.

In the tone ordering 147 and the rate converter 148 in the configuration of the receiving system, the operation opposite to the above operation is performed. Also, the VDSL terminal side device (VT
The same operation is performed when data (US) is transmitted from the U-R) to the VDSL station-side device (VTU-C).

As described above, according to the third embodiment, a method of transmitting uplink and downlink data by frequency division using a predetermined frequency as a threshold, and a method of transmitting uplink and downlink data by time division And transmitting the data by dividing the data by the threshold value, and multiplexing and transmitting fast data requiring a small delay time and interleaved data requiring a small data error. By transmitting the fast data preferentially, interference noise due to the TCM-ISDN communication system is avoided, transmission in the TDD system is reduced as much as possible, and data with different requests is processed. It is possible to transmit data flexibly and efficiently according to the demand while maintaining the consistency with the above.

As in the above embodiment, the threshold value of the frequency that separates the FDD system from the TDD system is 1.1.
The value is not limited to MHz, and another value may be used according to the state of interference, noise, transmission path, transmission speed, and the like. Also, for example, two thresholds are provided and divided into three frequency bands of a high frequency band, a medium frequency band, and a low frequency band. The high frequency band is a TDD system, and the middle frequency band is an FDD system. In the low frequency band, a plurality of threshold values may be provided, for example, data is transmitted by the TDD method.

Also, as in the above embodiment, the upper limit of the frequency used by the FDD system is 17.6 MHz in FIG. 3, but in accordance with the increase or decrease of the used bandwidth of the FDD system,
Other values may be used.

[0084] Further, in the present embodiment, the number of bits per symbol of the interleaved data bits t _f per one symbol of fast data 16 bits, transmitted before rate conversion to transmit before rate conversion t _i is 8 bits, S / N measured during training period
FDD method (tone number # 26)
The number of bits per symbol t_fd that can be transmitted
Although the case where d_max is 12 bits, 18 bits, and 32 bits has been described, similar effects can be obtained by using other values.

Further, in the present embodiment, as in the first embodiment, a method of transmitting uplink and downlink data by frequency division using a predetermined frequency as a threshold value, and a method of transmitting uplink and downlink data by time division A case has been described in which data is transmitted by dividing the transmission method by the threshold value.
Similarly to the above, a predetermined frequency is set as a threshold value, and a method of transmitting uplink and downlink data by frequency division and a method of transmitting uplink and downlink data by frequency division and time division are divided by the threshold value. The same effect can be obtained when data is transmitted by using the same method.

[0086] Figure 17 is a t _f> t_fdd_max, are explanatory views showing the operation of the rate converter 47 and a tone ordering 49 for assigning data of the downlink (DS), tone allocated in (c) of FIG. 17 It is the same as FIG. 14 except for the difference.

[0087] Figure 18 is a t _f> t_fdd_max, are explanatory views showing the operation of the rate converter 47 and a tone ordering 49 for assigning data of the uplink (US), tone allocated in (c) of FIG. 18 It is the same as FIG. 14 except for the difference.

[0088] Figure 19 is a t _f ≦ t_fdd_max and _{t (= t i + t f} )> t_fdd_max, there is an explanatory view showing the operation of the rate converter 47 and a tone ordering 49 for assigning data of the downlink (DS) 19 except that the tone to be assigned is different in FIG.

[0089] Figure 20 is a t _f ≦ t_fdd_max and _{t (= t i + t f} )> t_fdd_max, there is an explanatory view showing the operation of the rate converter 47 and a tone ordering 49 for assigning data of the uplink (US) 20 except that the tones to be assigned are different in (c) of FIG.

FIG. 21 shows that t (= t _i + t _f ) ≦ t_fdd
FIG. 22 is an explanatory diagram showing the operation of the rate converter 47 and the tone ordering 49 in the case of _max. FIG. The operation for transmission is the same as in FIG.

Also, FIGS. 14, 15, 17, 18,
In FIGS. 19 and 20, dummy bits are inserted at the end of the 45 symbols after the rate converter, but dummy bits may be inserted at the forefront and intermediate portions of the 45 symbols or uniformly in each symbol. However, it is not limited to this.

Further, in this embodiment, the case where the fast data is preferentially transmitted by the FDD system has been described. However, the FDD system, the TDD system, the FDD system, and the TDD system
Fast data may be preferentially transmitted regardless of these methods.

Further, the functions shown using the functional configuration diagram in the above description may be realized by H / W or S / W.

[0094]

As described above, a method of transmitting uplink and downlink data by frequency division using a predetermined frequency as a threshold value and a method of transmitting uplink and downlink data by time division are described above. By transmitting the data divided by the threshold value, it is possible to transmit the data efficiently while maintaining the consistency with other countries.

Further, a method of transmitting uplink and downlink data by frequency division using a predetermined frequency as a threshold value and a method of transmitting uplink and downlink data by frequency division and time division are described as the threshold values. By transmitting data separately, it is possible to transmit data efficiently while maintaining consistency with other countries.

Also, a method of transmitting uplink and downlink data by frequency division using a predetermined frequency as a threshold value, a method of transmitting uplink and downlink data by time division, and a method of transmitting uplink and downlink data by frequency division By transmitting data by dividing the data transmission method and the time-division transmission method by the threshold value, it is possible to transmit data efficiently while maintaining consistency with foreign countries.

Further, by transmitting data by giving priority to the method of transmitting uplink and downlink data by frequency division among the above-mentioned methods, it is possible to maintain consistency with foreign countries,
Transmission can be performed efficiently.

When multiplexing and transmitting fast data requiring a small delay time and interleaved data requiring a small data error, the fast data is preferentially transmitted. Thus, transmission can be performed flexibly and efficiently according to requirements while maintaining consistency with other countries.

[0099] In addition, by transmitting data by dividing the method of transmitting uplink and downlink data by frequency division and the method of transmitting uplink and downlink data by time division, it is possible to maintain consistency with foreign countries. In addition, transmission can be performed efficiently.

Further, by separately transmitting a method of transmitting uplink and downlink data by frequency division and a method of transmitting uplink and downlink data by frequency division and time division, data transmission to and from other countries is achieved. Efficient transmission can be achieved while maintaining consistency.

A method of transmitting uplink and downlink data by frequency division, a method of transmitting uplink and downlink data by time division, and a method of transmitting uplink and downlink data by frequency division and time division. By transmitting data separately, it is possible to transmit data efficiently while maintaining consistency with foreign countries.

[Brief description of the drawings]

FIG. 1 is a functional configuration diagram showing a transmission function of a conventional communication device.

FIG. 2 is a functional configuration diagram showing a reception function of a conventional communication device.

FIG. 3 is an explanatory diagram showing an outline of a communication method according to the present invention.

FIG. 4 is an explanatory diagram showing assignment of data to tones in the communication method according to the present invention.

FIG. 5 is an explanatory diagram showing the operation of the communication device according to the present invention.

FIG. 6 is an explanatory diagram showing the operation of the communication device according to the present invention.

FIG. 7 is an explanatory diagram showing an outline of a communication method according to the present invention.

FIG. 8 is an explanatory diagram showing assignment of data to tones in the communication method according to the present invention.

FIG. 9 is an explanatory diagram showing the operation of the communication device according to the present invention.

FIG. 10 is an explanatory diagram showing the operation of the communication device according to the present invention.

FIG. 11 is an explanatory diagram showing the operation of the communication device according to the present invention.

FIG. 12 is an explanatory diagram showing the operation of the communication device according to the present invention.

FIG. 13 is an explanatory diagram showing an outline of a communication method according to the present invention.

FIG. 14 is an explanatory diagram showing the operation of the communication device according to the present invention.

FIG. 15 is an explanatory diagram showing the operation of the communication device according to the present invention.

FIG. 16 is an explanatory diagram showing the operation of the communication device according to the present invention.

FIG. 17 is an explanatory diagram showing the operation of the communication device according to the present invention.

FIG. 18 is an explanatory diagram showing the operation of the communication device according to the present invention.

FIG. 19 is an explanatory diagram showing the operation of the communication device according to the present invention.

FIG. 20 is an explanatory diagram showing the operation of the communication device according to the present invention.

FIG. 21 is an explanatory diagram showing the operation of the communication device according to the present invention.

FIG. 22 is an explanatory diagram showing a state of interference noise between transmission paths.

FIG. 23 is an explanatory diagram showing an outline of a conventional communication method.

FIG. 24 is an explanatory diagram showing an outline of a conventional communication method.

[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 Tone Ordering 50 Constellation Encoder / Gain Scaling 51 Inverse 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 Tone Ordering 148, 149 Rate Converter 150 Dyne Tarleave 151, 152 Descramble Forward Error Correction 153, 154 Cyclic Redundancy Check 155 Multiplex / Sync Control

Claims (8)

[Claims] 1. A method of transmitting uplink and downlink data by frequency division using a predetermined frequency as a threshold, and a method of transmitting uplink and downlink data by time division using the threshold. Communication device for transmitting. 2. A method of transmitting uplink and downlink data by frequency division using a predetermined frequency as a threshold, and a method of transmitting uplink and downlink data by frequency division and time division. A communication device that transmits data separately. 3. A method of transmitting uplink and downlink data by frequency division using a predetermined frequency as a threshold, a method of transmitting uplink and downlink data by time division, and a method of dividing uplink and downlink data by frequency division. And a method of transmitting data by dividing the transmission method by time-division with the threshold value. 4. The communication apparatus according to claim 1, wherein the data is transmitted by preferentially using a method of transmitting uplink and downlink data by frequency division among the above methods. . 5. When multiplexing and transmitting fast data requiring a small delay time and interleaved data requiring a small data error,
The communication device according to any one of claims 1 to 4, wherein the fast data is transmitted preferentially. 6. A communication method for transmitting data by dividing a method of transmitting uplink and downlink data by frequency division and a method of transmitting uplink and downlink data by time division. 7. A communication method for transmitting data by dividing a method of transmitting uplink and downlink data by frequency division and a method of transmitting uplink and downlink data by frequency division and time division. 8. A method of transmitting uplink and downlink data by frequency division, a method of transmitting uplink and downlink data by time division, and a method of transmitting uplink and downlink data by frequency division and time division. A communication method that separates and transmits data.