WO2012167439A1

WO2012167439A1 - Method, appratus and communication device for signal transmission to measure lines

Info

Publication number: WO2012167439A1
Application number: PCT/CN2011/075577
Authority: WO
Inventors: 石操; 罗辉
Original assignee: 华为技术有限公司
Priority date: 2011-06-10
Filing date: 2011-06-10
Publication date: 2012-12-13
Also published as: CN102257799A; CN102257799B

Abstract

A method, an apparatus and a communication device for signal transmission to measure lines are disclosed in the embodiments of the present invention. The method includes the following steps: collecting framing parameters corresponding to signals transmitted in the lines of multiple activated digital subscriber line(xSDL) lines; calculating a pulse noise protection parameter corresponding to each of activated lines according to the framing parameters, and determining the transmission interval for transmitting measurement signals and the number of the measurement signals transmitted in the transmission interval according to the pulse noise protection parameter; transmitting the measurement signals with said number in the determined transmission interval in each of activated lines. Measurement signals are transmitted discontinuously in the embodiments of the present invention, so as to make the crosstalk generated by the measuring signals intermittently appear. Therefore the characteristic that the xDSL technology supports pulse noise protection can be utilized to reduce the influence of crosstalk on other lines.

Description

Signal transmitting method, device and communication device for measuring line

The present invention relates to the field of data communications, and more particularly to a signal transmitting method, apparatus, and communication device for measuring a line. Background technique

xDSL is a general term for all DSL (Digital Subscriber Line) technologies. It is a high-speed data transmission technology that uses a telephone twisted pair (UTP) to transmit UTS (Unshielded Twist Pair). In addition to IDSL (DSL based on ISDN (Integrated Services Digital Network)) and DSL for baseband transmission such as SHDSL (Symmetric High-speed DSL), the passband transmission xDSL utilizes frequency division multiplexing. The xDSL and the POTS (Plain Old Telephone Service) coexist on the same pair of twisted pairs, wherein xDSL occupies a high frequency band, and the POTS occupies a baseband portion below 4 KHz. The xDSL for passband transmission uses DMT (Discrete Multitone) modulation. A system that provides multi-channel xDSL signal access is called a DSLAM (DSL Access Multiplexer).

As the frequency band used by xDSL technology increases, crosstalk, especially in high frequency bands, is becoming more and more prominent. Crosstalk is usually classified into "Near End Crosstalk (NEXT)" and "Remote Crosstalk (FEXT)" by characteristics. Since the xDSL uplink and downlink channels use frequency division multiplexing, generally NEXT does not cause too much harm to system performance. However, FEXT will seriously affect the transmission performance of the line. When multiple users in a bundle of cables are required to open xDSL services, some line rates are low, performance is unstable, or even impossible to open due to far-end crosstalk (FEXT), which ultimately results in a lower DSLAM outgoing rate. That is to say, not all user twisted pairs can open the xDSL service at a certain point. Lines that cannot open xDSL services need to be trouble-shooted or even completely replaced to open xDSL services. This process requires a lot of manpower and material resources, which greatly increases the operator's operating costs.

In order to effectively perform line measurement in an xDSL system, a technique called SELT (Single Ended Loop Test) is proposed, which measures, checks and locates faults by means of automatic measurement.

However, in the above SECT technique, the SECT measurement signal is generally in a relatively wide spectrum. Continuous transmission is performed directly within the range. Therefore, the transmitted signal will cause crosstalk to nearby lines. Crosstalk will cause errors in nearby lines, and in severe cases, dropped lines will occur. Summary of the invention

Embodiments of the present invention provide a signal transmission method, apparatus, and communication device for measuring a line, which can reduce the influence of crosstalk generated when a measurement signal is transmitted on other users.

According to an aspect of an embodiment of the present invention, a signal transmission method for a measurement line is provided, comprising: collecting framing parameters corresponding to signals transmitted on lines in a plurality of activated xDSL lines; a frame parameter, calculating an impulse noise protection parameter corresponding to each activated line, determining a transmission interval for transmitting the measurement signal and a number of measurement signals transmitted in the transmission interval according to the impulse noise protection parameter; The determined transmission interval transmits the number of measurement signals on each activated line.

According to another aspect of an embodiment of the present invention, there is provided a signal transmitting apparatus for measuring a line, comprising: a parameter collecting unit configured to collect a signal corresponding to a signal transmitted on a line in a plurality of activated xDSL lines a frame parameter; a determining unit, configured to calculate, according to the framing parameter, an impulse noise protection parameter corresponding to each activated line, and determine, according to the impulse noise protection parameter, a transmission interval for transmitting the measurement signal and The number of measurement signals transmitted in the transmission interval; the measurement data transmitting unit configured to transmit the number of measurement signals on each activated line at the determined transmission interval.

According to another aspect of an embodiment of the present invention, there is provided a communication apparatus comprising the above-described signal transmitting apparatus for measuring a signal.

The embodiment of the present invention determines the transmission interval for transmitting measurement data and the number of measurement signals transmitted in the transmission interval according to the pulse protection parameter, and then transmits the determined number of measurement signals at the determined transmission interval, The measurement signal is sent intermittently, so that the impulse noise protection mechanism in the xDSL system can be utilized to reduce the influence of crosstalk on other lines. DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments or the prior art description will be briefly described below. It is obvious that the drawings in the following description are only some implementations of the present invention. For example, other drawings may be obtained from those of ordinary skill in the art in light of the inventive work. 1 is a schematic block diagram of a system to which a signal transmission method for a measurement line is applied according to an embodiment of the present invention;

2 is a flowchart of a signal transmission method for measuring a line according to an embodiment of the present invention; FIG. 3 is a schematic diagram of a specific process of determining a transmission interval according to an impulse noise protection parameter in FIG. 2;

4 is a schematic diagram of a specific process of determining a transmission interval according to the number of symbols to which a code word is spread in a signal transmitted on each activated line in FIG. 3;

5 is a schematic diagram of a specific process of determining the number of measurement signals transmitted in the transmission interval according to an impulse noise protection parameter in FIG. 2;

6 is a schematic block diagram of a signal transmitting apparatus for measuring a line according to an embodiment of the present invention. detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

Embodiments of the present invention provide a signal transmission method for measuring a line. First, a system for applying a signal transmission method for measuring a line provided by an embodiment of the present invention will be described by way of example.

1 is a schematic block diagram of a system 10 for applying a signal transmission method for measuring a line according to an embodiment of the present invention.

Referring to FIG. 1, the system 10 includes a DSLAM (DSL Access Multiplexer) 11, the DSLAM 11 includes a plurality of ports P1, P2 P _n , and each of the plurality of ports is connected to multiple lines. One end of a corresponding line of L ₂ L _n t . The other end of the line, the _second line of the L ₂ L _n and a corresponding one of a plurality of CPEs (Customer Premises Equipment) 12 , CPE 12 ₂ , ..., CPE 12 _n Connected, where n represents a natural number. In system 10, DSLAM 11 transmits measurement signals via respective ports, and the measurement signals are transmitted to the corresponding CPEs via respective lines.

Although the present invention is described herein as applying the signal transmission method for measuring a line provided by the embodiment of the present invention in the above system, the embodiment of the present invention is not limited thereto. For example, the above-mentioned DSLAM 11 can be replaced with xTU-C (Transceiver). Unit at the Central side, the transceiver unit on the center side). A specific embodiment of a signal transmission method for measuring a line provided by an embodiment of the present invention is described in detail below.

The signal transmission method for measuring a line provided by the embodiment of the invention intermittently transmits the SELT measurement signal, so that the crosstalk generated by the SELT measurement signal occurs intermittently. Therefore, the characteristics of the impulse noise protection can be supported by the xDSL technology to reduce crosstalk to other The impact of the line.

2 is a flow chart of a signal transmission method for measuring a line according to an embodiment of the present invention. Referring to Figure 2, in step 201, framing parameters corresponding to signals transmitted on lines in a plurality of activated xDSL lines are collected.

Specifically, before transmitting the SELT measurement signal, first determine the set of activated lines connecting the same DSLAM: ! ^, L ₂ L _N , where i is a natural number greater than or equal to 1, and N is the number of activated lines connecting the same DSLAM. Although described in the present embodiment as determining a set of activated lines connecting the same DSLAM, embodiments of the present invention are not limited thereto, and for example, it may be determined that connected two or more DSLAMs are activated as needed. Collection of lines.

The framing parameters corresponding to the signals transmitted on each of the lines in the set are collected. Methods for collecting framing parameters of signals transmitted on the line are well known to those skilled in the art and therefore will not be described in detail herein.

In addition, in an xDSL system, a framing parameter is a parameter for establishing a frame. For example, in a VSDL (Very High Speed Digital Subscriber Line) system, the framing parameters include: interleaving depth, The number of redundant bytes in an RS (Reed-Solomon) codeword, the number of interleaved blocks included in an RS block, included in each DMT (Discrete Multitone) symbol The number of bits, the size of the interleaving block, the length of an RS codeword, etc. (see ITU-T Recommendation G993.2, Very high speed digital subscriber line transceivers 2 (VSDL2)) „ although in this embodiment by way of example The foregoing framing parameters are listed, but the embodiment of the present invention is not limited thereto. For example, in addition to the parameters listed above, the embodiment of the present invention may further include other framing parameters, or may not include the framing parameters. That is, the framing parameters employed can be increased or decreased as needed.

At step 202, an impulse noise protection parameter corresponding to each activated line is calculated according to a framing parameter, and a transmission interval Q for transmitting the measurement signal and a transmission interval are determined according to the impulse noise protection parameter. The number of measurement signals sent in P.

In an xDSL system, the impulse noise protection parameter indicates error correction of a signal transmitted on the line Capability, which can be represented by the number of symbols of a certain size in the signal that can be completely corrected by the error correction code (see ITU-T Recommendation G993.2, Very high speed digital subscriber line transceivers 2 (VS/) L2 )).

In practical applications, the NEXT signal generated by the SELT measurement signal has less influence on adjacent lines, so only the downlink impulse noise protection parameters can be calculated.

Impulse noise protection parameters can be calculated in a number of ways. For example, in a VDSL system, the impulse noise protection parameter INP_no_erasure(i) corresponding to each activated line can be calculated according to the following formula (1):

R

8x D _D ( )x _P (

2 xq _p d)

INP — no erasure (i)

8 x( Ό (ί) χ Ι (ί)) χ { ^ ^ )

P ^P 2x N _{FEC p} (i)

T) ... , where i represents the line number;

D _p (0 represents an interleaving depth;

R _p (0 represents the number of redundant bytes in an RS codeword;

Representing the number of interleaved blocks included in one RS block;

L _p (0 represents the number of bits included in each DMT symbol;

/ _P ( ) indicates the size of the interleaved block;

W _F£Cp ( ) represents the length of an RS codeword.

In addition, in the xDSL communication system, in order to enhance the anti-interference ability of data to burst errors, an interleaving technique is usually used to spread an RS codeword into multiple DMT symbols before transmission, for example, in a VDSL system, The number of symbols to which an RS codeword is spread in the signal transmitted on each activated line is calculated according to the following formula (2):

8x / _D (i) D _D (z)

RS _ Expend (i) = ^p ——— ^ -—

^L ') ...(2),

Where i, L _p (i), and D _p W in the formula (2) are the same as in the formula (1), and therefore the description will not be repeated. Substituting the formula (2) into the formula (1), the following formula (3) can be obtained:

R (;')

INP — no _ erasure (i) = RS _ Expend (i) x ( ^E

^ x N _FEC (i)

(3), in the above formula, / ³ - no eraTM^ (0 indicates an impulse noise protection parameter corresponding to the activated line i, RS_Expendii) indicates transmission on the activated line i The number of symbols to which an RS code word is spread, R _p ( )/2 indicates the number of bytes that an RS code word can correct, N _{F £Cp} (0 indicates the length of a code word, which can be seen from above In the xDSL system, the impulse noise protection parameter can be expressed in the symbol to which a codeword is spread. When the impulse noise interference occurs, the number of erroneous symbols can be completely corrected by the error correction code. Therefore, according to the impulse noise protection parameter The transmission interval for transmitting the measurement signal may be determined according to the number of symbols to which the one codeword is spread. The transmission interval is represented by the number of symbols, but the embodiment of the present invention is not limited thereto, for example, The transmission interval can also be represented by the length of time, which can be determined as needed.

3 is a diagram showing a specific process of determining a transmission interval according to an impulse noise protection parameter in FIG. 2. Referring to FIG. 3, in step 301, one of signals transmitted on each activated line is calculated according to a framing parameter. The number of symbols to which the codeword is spread. As described above, the calculation of step 301 can be performed according to the formula (2).

At step 302, a transmission interval for transmitting the measurement signal is determined based on the number.

4 is a diagram showing a specific process of determining a transmission interval in accordance with the number of symbols to which one code word is spread in a signal transmitted on each activated line in FIG.

Referring to FIG. 4, in step 401, the maximum number of symbols in the number of symbols to which a codeword is spread in the calculated signal of each activated line upload is determined. RS_Expend_max The maximum number determined above «Expend The process of _max can be expressed as:

RS _ Expend _ max max(RS _ Expend ( ))

... (4).

Where i denotes the line number and Ν denotes the number of activated lines.

At step 402, the transmission interval is determined to be greater than or equal to the maximum number.

The above process of determining the transmission interval can be expressed as:

Q≥RS _ Expend _ ax ... (5).

FIG. 5 is a diagram showing the transmission in the transmission interval according to the impulse noise protection parameter in FIG. Schematic diagram of a specific process for measuring the number of signals.

Referring to FIG. 5, in step 501, a minimum pulse protection parameter / NP - no erasure min among the calculated impulse noise protection parameters is determined, and the above process of determining the minimum pulse protection parameter may be

In step 502, ^ INP _ no _ erasure _ min is greater than 1, and when INP _ no _ erasure _ min is greater than 1, in step 503, the number P of measurement signals transmitted in the transmission interval Q is determined to be 1 and The value between ( - e we - min -1), when /to em^-min is not greater than 1, in step 504, the number P of measurement signals transmitted in the transmission interval Q is determined to be 1. The above process of determining the number P of measurement signals transmitted in the transmission interval Q can be expressed as:

If INP no- erasure _ min < 1

... (7).

No— erasure min- 1 if INP no- erasure min > 1

Although described herein as determining the range of the number P as a range between 1 and (minimum pulse protection parameter-1), embodiments of the present invention are not limited thereto, and for example, the range of the number P may also be Determined to be between 1 and the minimum pulse protection parameter /N/ ³ - eraTOre min, or the range of the quantity P can be determined to be 1 and less ( /NP_ « ₀ - erasure_ min - 1 The range between the values of the above, all of which can implement the embodiments of the present invention, only the performance achieved is different.

Returning to Fig. 2, in step 203, the measurement signal of the quantity P is transmitted on each activated line with the determined transmission interval Q.

In this embodiment, the transmission interval Q may take a fixed value, that is, the measurement signal is periodically transmitted, and the transmission interval Q may also be changed. For example, the transmission interval in the first transmission is Q1, and the transmission interval in the subsequent transmission may be Different from Q1, it is sufficient that the transmission interval Q falls within the range of the above-mentioned determined transmission interval. Further, the number P of measurement signals transmitted each time may be fixed or varied as long as the number P falls within the range of the above-mentioned determined number of transmissions.

As described above, according to the signal transmission method for measuring a line according to an embodiment of the present invention, the SELT measurement signal of the number P is transmitted on the activated line within the transmission interval Q without transmitting other signals, and therefore, for the activated The line, even if crosstalk is generated for the number P of data in the transmission interval Q, the influence of these crosstalk can be completely eliminated by the impulse noise protection mechanism of the xDSL system. Therefore, compared with the conventional SELT measurement technique, the method of the embodiment of the present invention is more Plus reliable.

The signal transmitting apparatus for measuring a line and the communication apparatus including the signal transmitting apparatus provided by the embodiment of the present invention will be described in detail below.

The signal transmitting apparatus for measuring a line provided by the embodiment of the present invention intermittently transmits a SELT measurement signal, so that crosstalk generated by the SELT measurement signal is intermittently generated. Therefore, the characteristics of the impulse noise protection can be supported by xDSL technology to reduce crosstalk to other The impact of the line.

Figure 6 is a schematic block diagram of a signal transmitting device 60 for measuring a line in accordance with an embodiment of the present invention.

As shown in Fig. 6, the signal transmitting device 60 includes a parameter collecting unit 61, a determining unit 62, and a measuring signal transmitting unit 63.

The parameter collection unit 61 is for collecting framing parameters corresponding to signals transmitted on lines in a plurality of activated xDSL lines. The determining unit 62 is configured to calculate, according to the framing parameter, an impulse noise protection parameter corresponding to each activated line, and determine, according to the impulse noise protection parameter, a transmission interval and a quantity of measurement signals sent in the transmission interval . The measurement data transmitting unit 63 is configured to transmit the number of measurement signals on each activated line at the determined transmission interval.

The various portions of the signal transmitting device 60 can perform the various processes described above with reference to Figures 2 through 5, and are not described again in order to avoid redundancy.

For example, according to an embodiment of the present invention, the determining unit 62 determines the transmission interval for transmitting the measurement signal based on the number of symbols to which one code word is spread among the signals transmitted on each activated line, based on the impulse noise protection parameter.

According to an embodiment of the present invention, the determining unit 62 calculates the number of symbols to which one codeword is spread among the signals transmitted on each activated line according to the framing parameter, and determines the transmission interval according to the number.

According to an embodiment of the present invention, the determining unit 62 determines a maximum number among the calculated number of symbols to which a codeword is spread among the signals transmitted on each activated line, and determines the transmission interval to be greater than or equal to The maximum number.

According to an embodiment of the present invention, the determining unit 62 determines the number of measurement signals transmitted in the transmission interval according to the following manner: determining a minimum pulse protection parameter among the calculated pulse protection parameters; when the minimum pulse protection parameter When less than or equal to 1, the number is determined to be 1, and when the minimum pulse protection parameter is greater than 1, the number is determined to be a value between 1 and (minimum pulse protection parameter -1). According to an embodiment of the present invention, the determining unit 62 calculates impulse noise protection parameters corresponding to each activated line and calculates signals transmitted on each activated line according to the above formulas (1) and (2), respectively. The number of symbols to which a codeword is spread.

Furthermore, according to an embodiment of the present invention, the above-described signal transmitting apparatus for measuring a line may be implemented to be included in a communication device, including but not limited to a DSLAM, which may be used for measuring a line as needed. The signal transmitting device is included in other communication devices.

The above is only the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope of the present invention. It should be covered by the scope of the present invention. Therefore, the scope of the invention should be determined by the scope of the claims.

Claims

Rights request

A signal transmission method for measuring a line, comprising:

Collecting framing parameters corresponding to signals transmitted on lines in a plurality of activated XDSL lines;

Calculating, according to the framing parameter, an impulse noise protection parameter corresponding to each activated line, determining a transmission interval for transmitting the measurement signal and a measurement signal sent in the transmission interval according to the impulse noise protection parameter quantity;

The quantity of measurement signals is transmitted on each activated line at the determined transmission interval.

2. The signal transmitting method according to claim 1, wherein determining a transmission interval for transmitting the measurement signal according to the impulse noise protection parameter comprises: according to the impulse noise protection parameter, according to the The number of symbols to which one codeword is spread out of the signal transmitted on each activated line determines the transmission interval for transmitting the measurement signal.

3. The signal transmitting method according to claim 2, wherein, according to said impulse noise protection parameter, a number of symbols to which one codeword is spread according to a signal transmitted on said each activated line The transmission interval for determining the measurement signal to be transmitted includes:

Calculating, according to the framing parameter, a number of symbols to which a codeword is spread among signals transmitted on each activated line;

A transmission interval for transmitting the measurement signal is determined according to the number.

4. The signal transmitting method according to claim 3, wherein determining a transmission interval for transmitting the measurement signal according to the number comprises:

Determining a maximum number of the number of symbols to which a codeword is spread among the calculated signals transmitted on each of the activated lines;

The transmission interval is determined to be greater than or equal to the maximum number.

5. The signal transmitting method according to claim 1, wherein determining the number of measurement signals transmitted in the transmission interval according to the pulse noise protection parameter comprises:

Determining a minimum pulse protection parameter among the calculated pulse protection parameters;

When the minimum pulse protection parameter is less than or equal to 1, the quantity is determined to be 1, and when the minimum pulse protection parameter is greater than 1, the quantity is determined to be at 1 and (minimum pulse protection parameter -1) The value between.

6. The signal transmitting method according to claim 1, wherein calculating an impulse noise protection parameter corresponding to each of the activated lines comprises: calculating corresponding to the Impulse noise protection parameter INP _ - no _ erasure(i) for each activated line

8x D _p ( ) x ^{R p(?)}

p 2 x q (i)

INP _ no _ erasure (i) =

L (i)

R

8 x D _D ( _Z -) . ('')

N _FEC Ai)

R _B (

8 x( O (i) x l (i)) x(

2 x N _FEC (i)

Where i represents the line number;

D _p represents the interleaving depth;

R _p ( ) represents the number of redundant bytes in an RS codeword;

Representing the number of interleaved blocks included in one RS block;

Represents the number of bits included in each DMT symbol;

/ _ρ ( _ζ ·) indicates the size of the interleaved block;

N _F£Cp ( ) represents the length of an RS codeword.

7. The signal transmitting method according to claim 3, wherein calculating the number of symbols to which one codeword is spread among the signals transmitted on each activated line comprises: determining the presence in accordance with the following formula The number of symbols to which a codeword is spread to the signal transmitted on each activated line RS_Expend(i):

RS _ Expend (i) = ^p ——— ^ where i denotes the line number;

L^) indicates the number of bits included in each DMT symbol;

/ _p « represents the size of the interleaved block;

D _p ( ) indicates the interleaving depth.

A signal transmitting apparatus for measuring a line, comprising: a parameter collecting unit, configured to collect a framing parameter corresponding to a signal transmitted by a line of the plurality of activated xDSL lines;

a determining unit, configured to calculate, according to the framing parameter, an impulse noise protection parameter corresponding to each activated line, and determine, according to the impulse noise protection parameter, a signal used to send the measurement signal a transmission interval and a number of measurement signals transmitted in the transmission interval;

And a measurement data transmitting unit configured to transmit the quantity of the measurement signal on each activated line at the determined transmission interval.

9. The signal transmitting apparatus according to claim 8, wherein said determining unit diffuses a code word according to said impulse noise protection parameter according to a signal transmitted on said each activated line The number of symbols determines the transmission interval for transmitting the measurement signal.

The signal transmitting apparatus according to claim 9, wherein the determining unit calculates, according to the framing parameter, a symbol to which a codeword is spread among signals transmitted on each activated line The number of the transmission intervals is determined based on the number.

The signal transmitting apparatus according to claim 10, wherein said determining unit determines among the number of symbols to which a code word is spread among the calculated signals transmitted on said each activated line The maximum number of times, the transmission interval is determined to be greater than or equal to the maximum number.

The signal transmitting apparatus according to claim 8, wherein said determining unit determines the number of measurement signals transmitted in said transmission interval according to the following manner:

13. The signal transmitting apparatus according to claim 8, wherein the determining unit calculates an impulse noise protection parameter INP_no_erasure(i) corresponding to each of the activated lines according to the following formula:

R _P ")

8x D _p ( )

2 xq _p d)

INP _ no _ erasure (i)

L (i)

R _D (

8 x D _D ( _Z )

N _{FEC p} d)

/. ('·)

8 x( D _D (0 x /.( )) x( ^

2 x N _FEC (i)

Where i represents the line number; D _p () indicates the interleaving depth;

R _p (0 represents the number of redundant bytes in an RS codeword;

Representing the number of interleaved blocks included in one RS block;

Represents the number of bits included in each DMT symbol;

Indicates the size of the interleaved block;

Λ _£ () indicates the length of an RS codeword.

The signal transmitting apparatus according to claim 10, wherein said determining unit determines the number of symbols to which a code word is spread among signals transmitted on said each activated line according to the following formula ^ ):

8x / ii)xD _D ( )

RS Expend (i) = ^p ——— ^

― L _p W ,

Where i represents the line number;

Represents the number of bits included in each DMT symbol;

/ _p () indicates the size of the interleaved block;

D _p (0 represents the interleaving depth.

A communication device, comprising the signal transmitting apparatus according to any one of claims 8-14.