U.S. patent application number 12/941472 was filed with the patent office on 2011-02-24 for method and device for mapping and demapping a client signal.
This patent application is currently assigned to HUAWEI TECHNOLOGIES CO., LTD.. Invention is credited to Yao SHEN, Qiuyou WU.
Application Number | 20110044686 12/941472 |
Document ID | / |
Family ID | 42561397 |
Filed Date | 2011-02-24 |
United States Patent
Application |
20110044686 |
Kind Code |
A1 |
WU; Qiuyou ; et al. |
February 24, 2011 |
Method and Device for Mapping and Demapping A Client Signal
Abstract
A method and a device for mapping and demapping a client signal
are provided. The method for mapping a client signal includes:
dividing a part or all of a payload area of an Optical Channel
Payload Unit (OPU) or Optical channel Data Tributary Unit (ODTU)
into several sub-blocks, in which the sub-blocks have a size of N
bytes, and N is greater than or equal to 1; and mapping a client
signal to be transported to the sub-blocks of the payload area with
an N-byte granularity. In the technical solutions, when the client
signal is mapped, block mapping of the client signal is performed
by using a mapping granularity of a block, so that the complexity
of the mapping process of the client signal can be reduced, thereby
meeting requirements of multi-rate services.
Inventors: |
WU; Qiuyou; (Shenzhen,
CN) ; SHEN; Yao; (Shenzhen, CN) |
Correspondence
Address: |
Huawei Technologies Co., Ltd.;c/o Conley Rose, P.C.
5601 Granite Parkway
Plano
TX
75024
US
|
Assignee: |
HUAWEI TECHNOLOGIES CO.,
LTD.
Shenzhen
CN
|
Family ID: |
42561397 |
Appl. No.: |
12/941472 |
Filed: |
November 8, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/CN2010/070171 |
Jan 14, 2010 |
|
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12941472 |
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Current U.S.
Class: |
398/43 |
Current CPC
Class: |
H04J 3/1652 20130101;
H04J 2203/0089 20130101; Y10S 370/907 20130101 |
Class at
Publication: |
398/43 |
International
Class: |
H04J 14/00 20060101
H04J014/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 10, 2009 |
CN |
200910005200.5 |
Claims
1. A method for mapping a client signal, comprising: dividing a
part or all of a payload area of an Optical Channel Payload Unit
(OPU) into several sub-blocks, wherein the sub-blocks have a size
of N bytes, and N is greater than 1; calculating a block number of
the client signal to be transported according to the sub-block size
of the payload area, wherein the client signal has a block size of
N bytes; generating mapping overhead (OH) information which
comprises indication information of the block number of the client
signal to be transported, and mapping the mapping OH information to
an OH area, wherein the indication information of the block number
of the client to be transported comprises a bit reversal field and
an increment/decrement indication field, and the bit reversal field
and the increment/decrement indication field jointly indicate the
block number of the client signal through bit reversal; determining
a position distribution of the client signal to be transported in
the sub-blocks of the payload area by using the block number; and
mapping the client signal to be transported to corresponding
sub-blocks of the payload area with an N-byte granularity according
to the determined position distribution.
2. The method for mapping a client signal according to claim 1,
wherein determining the position distribution of the client signal
to be transported in the sub-blocks of the payload area by using
the block number comprises: determining the position distribution
of the client signal to be transported in the sub-blocks of the
payload area by performing a sigma-delta algorithm according to the
block number.
3. The method for mapping client signals according to claim 2,
wherein determining the position distribution of the client signal
to be transported in the sub-blocks of the payload area by
performing a sigma-delta algorithm according to the block number
comprises: if (i.times.C.sub.block)mod M<C.sub.block, the
i.sup.th sub-block of the payload area is a client signal
sub-block; and if (i.times.C.sub.block) mod M.gtoreq.C.sub.block,
the i.sup.th sub-block of the payload area is a stuff sub-block, in
which C.sub.block is the block number of the client signal, and M
is the total number of the divided sub-blocks of the OPU payload
area.
4. The method for mapping a client signal according to claim 3,
wherein determining the position distribution of the client signal
to be transported in the sub-blocks of the payload area by using
the block number comprises: obtaining a preset position
distribution of sub-blocks for bearing a stuff signal and
sub-blocks for bearing the client signal in the payload area
corresponding to the block number according to the block
number.
5. The method for mapping a client signal according to claim 1,
wherein the payload area comprises an adjustment region and a block
region, wherein the block region of the payload area is divided
into several sub-blocks having a size of N bytes, and wherein the
method further comprises: mapping several bytes of the client
signal to be transported to the adjustment region of the payload
area.
6. The method for mapping a client signal according to claim 5,
wherein the mapping OH information further comprises: indication
information of a byte number of the client signal borne by the
adjustment region.
7. A method for mapping client signals, comprising: dividing a part
or all of a payload area of an Optical Channel Payload Unit (OPU)
into several sub-blocks, wherein the sub-blocks have a size of N
bytes, and N is greater than 1; calculating a block number of the
client signal to be transported according to the sub-block size of
the payload area, wherein the client signal has a block size of N
bytes; determining a position distribution of the client signal to
be transported in the sub-blocks of the payload area by using the
block number; and mapping the client signal to be transported to
corresponding sub-blocks of the payload area with an N-byte
granularity according to the determined position distribution.
8. The method for mapping client signals according to claim 7,
wherein determining the position distribution of the client signal
to be transported in the sub-blocks of the payload area by using
the block number comprises: determining the position distribution
of the client signal to be transported in the sub-blocks of the
payload area by performing a sigma-delta algorithm according to the
block number.
9. The method for mapping client signals according to 8, wherein
determining the position distribution of the client signal to be
transported in the sub-blocks of the payload area by performing a
sigma-delta algorithm according to the block number comprises: if
(i.times.C.sub.block)mod M<C.sub.block the i.sup.th sub-block of
the payload area is a client signal sub-block; and if
(i.times.C.sub.block) mod M.gtoreq.C.sub.block, the i.sup.th
sub-block of the payload area is a stuff sub-block, in which
C.sub.block is the block number of the client signal, and M is the
total number of the divided sub-blocks of the OPU payload area.
10. The method for mapping client signals according to claim 7,
wherein determining the position distribution of the client signal
to be transported in the sub-blocks of the payload area by using
the block number comprises: obtaining a preset position
distribution of sub-blocks for bearing a stuff signal and
sub-blocks for bearing the client signal in the payload area
corresponding to the block number according to the block
number.
11. The method for mapping client signals according to claim 7,
wherein the payload area comprises an adjustment region and a block
region, wherein the block region of the payload area is divided
into several sub-blocks having a size of N bytes, and wherein the
method further comprises: mapping several bytes of the client
signal to be transported to the adjustment region of the payload
area.
12. The method for mapping client signals according to claim 11,
further comprising: generating mapping overhead (OH) information
which comprises indication information of a byte number of the
client signal borne by the adjustment region, and mapping the
mapping OH information to an OH area.
13. A device for mapping a client signal, comprising: a block
number calculating module, configured to calculate a block number
of a client signal to be transported according to a sub-block size
of a payload area of an Optical Channel Payload Unit (OPU), wherein
the payload area comprises several sub-blocks having a size of N
bytes, and N is greater than 1; a mapping control module,
configured to generate a control signal according to the block
number of the client signal, wherein the control signal is
configured to indicate a position distribution of the client signal
to be transported in the sub-blocks of the payload area; and a
mapping module, configured to map the client signal, to be
transported, in a buffer to corresponding sub-blocks of the payload
area with an N-byte granularity according to the control
signal.
14. The device for mapping a client signal according to claim 13,
wherein the mapping control module is specifically configured to
perform sigma-delta calculation according to the block number of
the client signal to generate a control signal, and the control
signal is configured to indicate the position distribution of the
client signal to be transported in the sub-blocks of the payload
area.
15. The device for mapping a client signal according to claim 14,
wherein the mapping control module is further configured to
generate mapping overhead (OH) information, and the mapping OH
information comprises indication information of the block number of
the client signal to be transported; and wherein the mapping module
is further configured to map the mapping OH information to an OH
area.
16. The device for mapping a client signal according to claim 13,
wherein the payload area comprises an adjustment region and a block
region, and the block region comprises several sub-blocks having a
size of N bytes; and wherein the mapping module is further
configured to map several bytes of the client signal in the buffer
to the adjustment region of the payload area.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of International
Application No. PCT/CN2010/070171, filed on Jan. 14, 2010, which
claims priority to Chinese Patent Application No. 200910005200.5,
filed on Feb. 10, 2009, both of which are hereby incorporated by
reference in their entireties.
FIELD OF THE TECHNOLOGY
[0002] The present invention relates to the field of communication
technology, and more particularly to a method and a device for
mapping and demapping a client signal.
BACKGROUND
[0003] The Optical Transport Network (OTN) technology is the core
technology for next-generation transport networks. The OTN has
strong Tandem Connection Monitoring (TCM) capability, abundant
Operation Administration Maintenance (OAM) capability, and out-band
Forward Error Correction (FEC) capability, can perform flexible
scheduling and management of large-capacity services, and is
applicable to backbone transport networks.
[0004] In order to meet the market demand, the International
Telecommunication Union-Telecommunication Standardization Sector
(ITU-T) has formulated a series of recommendations for the OTN,
among which the Recommendation G.709 is a standard mainly in regard
to the structure and mapping of OTN frames. The standard frame
structure defined in the Recommendation G.709 is as shown in FIG.
1. An OTN frame is a 4080*4 modular structure, and includes: a
Frame Alignment Signal (FAS), configured to provide a frame
synchronization and alignment function; Optical Channel Transport
Unit (OTU)-k (OTUk) Overhead (OH), configured to provide an
OTU-level network management function; Optical Channel Data Unit-k
(ODUk) OH, configured to provide a maintenance and operation
function; Optical Channel Payload Unit-k (OPUk) OH, configured to
provide a service adaptation function; an OPUk payload area, also
referred to as a payload area of the OTN frame, mainly configured
to provide a service bearer function; and an FEC area, configured
to provide an error detection and correction function.
[0005] In a scenario of transporting high rate service, if a client
signal is mapped to the OPUk payload through an existing mapping
method, the mapping process is rather complicated. For example,
when the client signal is mapped to OPU0 through an existing
mapping method based on the Generic Mapping Procedure (GMP), if the
bit width for processing is 16*8 bits, each clock cycle requires 16
times of sigma-delta calculation in order to complete the mapping
of the client signal in the clock cycle, so that the mapping
process is complicated.
SUMMARY
[0006] Accordingly, the present invention is directed to a method
and a device for mapping and demapping a client signal, which
simplifies the mapping and demapping process of a client signal,
and is applicable to multi-rate services.
[0007] In order to solve the above technical problems, the present
invention provides the following technical solutions.
[0008] In an embodiment, the present invention provides a method
for mapping a client signal, which includes: dividing a part or all
of a payload area of an Optical Channel Payload Unit (OPU) into
several sub-blocks, in which the sub-blocks have a size of N bytes,
and N is greater than 1; and calculating a block number of the
client signal to be transported according to the sub-block size of
the payload area, wherein the client signal has a block size of N
bytes; generating mapping overhead (OH) information which comprises
indication information of the block number of the client signal to
be transported, and mapping the mapping OH information to an OH
area, wherein the indication information of the block number of the
client to be transported comprises a bit reversal field and an
increment/decrement indication field, and the bit reversal field
and the increment/decrement indication field jointly indicate the
block number of the client signal through bit reversal; determining
a position distribution of the client signal to be transported in
the sub-blocks of the payload area by using the block number; and
mapping the client signal to be transported to corresponding
sub-blocks of the payload area with an N-byte granularity according
to the determined position distribution.
[0009] Further, in an embodiment, the present invention provides a
method for demapping a client signal, which includes: acquiring
indication information of a block number of a client signal borne
by a payload area of an OPU or ODTU, in which the blocks have a
size of N bytes, and N is greater than or equal to 1; determining a
position distribution of the client signal in sub-blocks of the
payload area by using the block number, in which the payload area
includes several blocks having a size of N bytes; and demapping the
client signal of the payload area according to the determined
position distribution.
[0010] Further, in an embodiment, the present invention provides a
device for mapping a client signal, which includes: a block number
calculating module, configured to calculate a block number of a
client signal to be transported according to a sub-block size of a
payload area of an OPU or Optical channel Data Tributary Unit
(ODTU), in which the payload area includes several sub-blocks
having a size of N bytes, and N is greater than or equal to 1; a
mapping control module, configured to generate a control signal
according to the block number of the client signal, in which the
control signal is configured to indicate a position distribution of
the client signal to be transported in the sub-blocks of the
payload area; and a mapping module, configured to map the client
signal, to be transported, in a buffer to corresponding sub-blocks
of the payload area with an N-byte granularity according to the
control signal.
[0011] Further, in an embodiment, the present invention provides a
device for demapping a client signal, which includes: a demapping
control module, configured to acquire a block number of a client
signal borne by a payload area of an OPU or ODTU, and generate a
control signal according to the block number, in which the control
signal is configured to indicate a position distribution of the
client signal in sub-blocks of the payload area, the payload area
includes several blocks having a size of N bytes, and N is greater
than or equal to 1; and a demapping module, configured to demap the
client signal borne by the payload area according to the control
signal generated by the demapping control module.
[0012] Further, in another embodiment, the present invention
provides a method for mapping a client signal, which includes:
dividing a part or all of a payload area of an Optical Channel
Payload Unit (OPU) into several sub-blocks, wherein the sub-blocks
have a size of N bytes, and N is greater than 1; calculating a
block number of the client signal to be transported according to
the sub-block size of the payload area, wherein the client signal
has a block size of N bytes; determining a position distribution of
the client signal to be transported in the sub-blocks of the
payload area by using the block number, and mapping the client
signal to be transported to corresponding sub-blocks of the payload
area with an N-byte granularity according to the determined
position distribution.
[0013] It can be seen from the above that the technical solutions
adopted by the embodiments of the present invention have the
following beneficial effects: when the client signal is mapped,
block mapping of the client signal is performed by using a mapping
granularity of a block, so that the mapping process of the client
signal can be simplified, thereby meeting requirements of
multi-rate services.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] To illustrate the technical solutions according to the
embodiments of the present invention and in the prior art more
clearly, the accompanying drawings for describing the embodiments
and the prior art are introduced briefly in the following.
Apparently, the accompanying drawings in the following description
are only some embodiments of the present invention, and persons of
ordinary skill in the art can derive other drawings from the
accompanying drawings without creative efforts.
[0015] FIG. 1 is a schematic structural view of an OTN frame
provided in the prior art;
[0016] FIG. 2 is a flow chart of a method for mapping a client
signal according to a first embodiment of the present
invention;
[0017] FIG. 3 is a schematic structural view of an OPUk payload
area and an OPUk OH area according to a second embodiment of the
present invention;
[0018] FIG. 4 is a flow chart of a method for mapping a client
signal according to the second embodiment of the present
invention;
[0019] FIG. 5 is another schematic structural view of the OPUk
payload area and the OPUk OH area according to the second
embodiment of the present invention;
[0020] FIG. 6 is a flow chart of a method for demapping a client
signal according to the second embodiment of the present
invention;
[0021] FIG. 7 is a schematic structural view of an OPUk payload
area and an OPUk OH area according to a third embodiment of the
present invention;
[0022] FIG. 8 is a flow chart of a method for mapping a client
signal according to the third embodiment of the present
invention;
[0023] FIG. 9 is a flow chart of a method for demapping a client
signal according to the third embodiment of the present
invention;
[0024] FIG. 10 is a schematic view of a device for mapping a client
signal according to a fourth embodiment of the present invention;
and
[0025] FIG. 11 is a schematic view of a device for demapping a
client signal according to a fifth embodiment of the present
invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0026] The present invention provides a method and a device for
mapping and demapping a client signal, which performs block mapping
of client data with a mapping granularity of a block, simplifies
the mapping process of the client signal, and is applicable to
multi-rate services.
[0027] Detailed description is given below through specific
embodiments.
[0028] In the implementation of the present invention, mapping of
the client signal based on a GMP mapping manner is taken as an
example for illustration, but the present invention is not limited
thereto, and other mapping manners may also be used.
[0029] An OPUk payload area may include several logically divided
sub-blocks having a size of N bytes, and preferably, N is an
integer not smaller than 1.
First Embodiment
[0030] Referring to FIG. 2, a method for mapping a client signal
according to a first embodiment of the present invention
specifically includes the following steps.
[0031] In Step 210, a part or all of a payload area of an OPU or
ODTU is divided into several sub-blocks, in which the sub-blocks
have a size of N bytes, and N is greater than or equal to 1.
[0032] In Step 220, a client signal to be transported is mapped to
the sub-blocks of the payload area with an N-byte granularity.
[0033] It can be seen that, in the embodiment of the present
invention, when the client signal is mapped, block mapping of the
client signal is performed by using a mapping granularity of a
block, so that the mapping process of the client signal is
simplified, thereby meeting requirements of multi-rate
services.
Second Embodiment
[0034] FIG. 3 is a schematic structural view of an OPUk payload
area and an OPUk OH area according to a second embodiment of the
present invention. Referring to FIG. 3, in this embodiment, the
OPUk payload area is logically divided into M sub-blocks each
having a size of N bytes, and the entire OPUk payload area has a
size of M*N bytes.
[0035] It should be understood that, the size of the logically
divided sub-blocks of the OPUk payload area may be arbitrary, that
is to say, N may be any value that is exactly divisible by the byte
number of the OPUk payload area.
[0036] Preferably, the OPUk payload area may be logically divided
into the sub-blocks according to a processing bit width of a
processor, and the size of the logically divided sub-blocks is a
submultiple of the processing bit width of the processor. For
example, assuming that the processing bit width of the processor is
16*8=128 bits, the size of the logically divided sub-blocks may be
16 bytes, 8 bytes, 4 bytes, 2 bytes, or 1 byte.
[0037] It should be noted that, this embodiment takes the 17.sup.th
to 3824.sup.th columns of the 1.sup.st to 4.sup.th rows of an OTN
frame (briefly referred to as a frame in the following) as an
example of the OPUk payload area for illustration, but is not
limited thereto, and the OPUk payload area may further include
reserved bytes in the OPUk OH area and/or other OH bytes for
bearing the client signal.
[0038] Referring to FIG. 4, a method for mapping a client signal
according to a second embodiment of the present invention
specifically includes the following steps.
[0039] In Step 401, a block number of a client signal to be borne
by a (K+n).sup.th frame is acquired.
[0040] It should be noted that, in an OTN frame structure, mapping
OH information carried by an OPUk OH area of a K.sup.th frame is
configured to indicate a block number of a client signal to be
borne by the (K+n).sup.th frame, a receiving end obtains mapping
related information of the client signal borne by the (K+n).sup.th
frame by receiving the mapping OH information carried by the OPUk
OH area of the K.sup.th frame, and thus can demap the (K+n).sup.th
frame to recover the client signal borne by the (K+n).sup.th frame
after receiving the (K+n).sup.th frame. Here, K is a positive
integer, and n is a natural number.
[0041] For example, the block number of the client signal to be
borne by the (K+n).sup.th frame may be determined according to the
bearer capability of the OTN frame and the size of the logically
divided sub-blocks of the OPUk payload area of the (K+n).sup.th
frame, and the size of the blocks of the client signal is identical
to the size of the logically divided sub-blocks of the OPUk payload
area, that is, N bytes.
[0042] A specific implementation may be as follows: a byte number
(represented by A in the following) of the client signal to be
borne by the (K+n).sup.th frame is determined first, the determined
byte number is divided by the size of the logically divided
sub-blocks of the OPUk payload area, and the result of exact
division can be taken as the block number (represented by
C.sub.block in the following) of the client signal to be borne by
the (K+n).sup.th frame, in which the relation between A,
C.sub.block, and N is A=C.sub.block*N+C, where C is the remainder.
The (K+n).sup.th frame needs to bear C.sub.block*N bytes of the
client signal, in which C.sub.block*N is not greater than the byte
number of the entire OPUk payload area of the (K+n).sup.th frame,
that is, not greater than the maximum bearer capability of the
(K+n).sup.th frame.
[0043] For example, assuming that the size of the logically divided
sub-blocks of the OPUk payload area of the (K+n).sup.th frame is
N=4, and the determined byte number of the client signal to be
borne by the (K+n).sup.th frame is A=14408, it can be further
determined that the block number of the client signal to be borne
by the (K+n).sup.th frame is C.sub.block=3602, in which
A=C.sub.block*N+0, that is to say, the (K+n).sup.th frame needs to
bear C.sub.block*N=14408 bytes of the client signal.
[0044] For another example, assuming that the size of the logically
divided sub-blocks of the OPUk payload area of the (K+n).sup.th
frame is N=4, and the determined byte number of the client signal
to be borne by the (K+n).sup.th frame is A=14407, it can be further
determined that the block number of the client signal to be borne
by the (K+n).sup.th frame is C.sub.block=3601, in which
A=C.sub.block*N+3, that is to say, the (K+n).sup.th frame needs to
bear C.sub.block*N=14404 bytes of the client signal, and the
remaining 3 bytes of the client signal may be borne by subsequent
frames.
[0045] In Step 402, mapping OH information is generated, and is
mapped to an OH area of the K.sup.th frame, in which the mapping OH
information includes indication information for indicating the
block number of the client signal to be borne by the (K+n).sup.th
frame.
[0046] The mapping OH information may include, but is not limited
to, indication information for indicating the size of the logically
divided sub-blocks of the OPUk payload area of the (K+n).sup.th
frame, the block number of the client signal to be borne by the
(K+n).sup.th frame, a mapping manner of the (K+n).sup.th frame and
the like.
[0047] A specific implementation may be as follows: the mapping OH
information is mapped to an OPUk OH area of the K.sup.th frame. The
structure of the OPUk OH area may be as shown in FIG. 3. The OPUk
OH area is located at the 15.sup.th and 16.sup.th columns of the
1.sup.st to 4.sup.th rows of the OTN frame, and includes 2*4 bytes.
The OPUk OH area may be divided as follows, but is not limited
thereto.
[0048] Three bytes of the 1.sup.st to 3.sup.rd rows of the
15.sup.th column of the OTN frame are reserved (RES) bytes, and 1
byte of the 4.sup.th row is a payload structure identifier (PSI)
byte. Assuming that a multiframe period of the OTN frame is 256,
PSI[0] may carry indication information of a payload type (PT)
identifier, that is, indication information of a mapping type, and
in this embodiment, the indication information carried by PSI[0]
indicates a GMP mapping manner; PSI[1] may carry indication
information for indicating the size of the logically divided
sub-blocks of the OPUk payload area, and may be, for example, 0X04,
indicating that the sub-block size is 4 bytes; and PSI[2] to
PSI[255] may serve as reserved bytes.
[0049] Three bytes of the 1.sup.st to 3.sup.rd rows of the
16.sup.th column of the OTN frame are JC1, JC2, and JC3 bytes, as
shown in FIG. 3. The JC1, JC2, and JC3 bytes form a 14-bit
C.sub.block field (bits C1, C2, . . . , C14), a 1-bit Increment
Indicator (II) field and a 1-bit Decrement Indicator (DI) field,
and an 8-bit cyclic redundancy check (CRC-8) field for performing
error correction coding on JC1 and JC2.
[0050] The C.sub.block field of the K.sup.th frame carries
indication information for indicating the block number of the
client signal to be borne by the (K+n).sup.th frame, and
specifically, the block number may be indicated in a variety of
manners. For example, the C.sub.block field of the K.sup.th frame
may directly carry the block number of the client signal borne by
the (K+n).sup.th frame; or the C.sub.block value of the
(K+n).sup.th frame may be indicated to the receiving end by means
of Ci bit reversal, and a corresponding relation between Ci bit
reversal and the change of the C.sub.block value is as shown in
Table 1, but is not limited thereto.
TABLE-US-00001 TABLE 1 Variable Cl C2 C3 C4 C5 C6 C7 C8 C9 C10 C11
C12 C13 C14 II DI Value 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 1
0 1 0 1 0 1 0 1 0 1 0 +1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 -1 0 1 1 0
0 1 1 0 0 1 1 0 0 1 1 0 +2 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 -2 Block
number 1 1 Others
[0051] As shown in Table 1, when C.sub.block of the client signal
borne by the (K+n).sup.th frame is incremented by 1 or 2 as
compared with the Cblock corresponding to the (K+n-1).sup.th frame,
a part of bits (Ci) in the C.sub.block field of the K.sup.th frame
are bit-reversed, and the II field is set to 1, so as to indicate
to the receiving end that the block number of the client signal
borne by the (K+n).sup.th frame is incremented by 1 or 2.
[0052] When C.sub.block of the (K+n).sup.th frame is decremented by
1 or 2, a part of Ci in the C.sub.block field of the K.sup.th frame
is bit-reversed, and the DI field is set to 1, so as to indicate to
the receiving end that the block number of the client signal borne
by the (K+n).sup.th frame is decremented by 1 or 2.
[0053] When the change of C.sub.block of the (K+n).sup.th frame is
greater than +2 or -2, both the II and DI fields of the K.sup.th
frame are set to 1, and the C.sub.block field directly carries the
C.sub.block value of the (K+n).sup.th frame, so as to indicate the
block number of the client signal borne by the (K+n).sup.th frame
to the receiving end, and CRC-8 verifies the C.sub.block value and
provides certain error correction capability.
[0054] When the C.sub.block value of the (K+n).sup.th frame does
not change, both the II and DI bits of the K.sup.th frame are set
to 0.
[0055] It can be seen that, the method for indicating the
C.sub.block value of the (K+n).sup.th frame to the receiving end
through bit reversal can further ensure the effectiveness of
transmission, is beneficial for error correction, and can reduce
the probability of error transmission.
[0056] Optionally, the OH bytes (which may be referred to as
C.sub.block bytes) of the 1.sup.st to 3.sup.rd rows of the
16.sup.th column of the OTN frame may use another structure to
carry indication information for indicating the C.sub.block value,
which is specifically as shown in FIG. 5, but is not limited
thereto: including a C.sub.block.sub.--.sub.base field (base number
field) of 3*5 bits and a C.sub.block.sub.--.sub.delta field
(variable field) of 3*3 bits.
[0057] The base number field of the C.sub.block bytes is configured
to carry a minimum value of the block number of the client signal
carried by each frame, the value is taken as a base number
(C.sub.block.sub.--.sub.base), and each frame carries the base
number; and the variable field of the C.sub.block bytes of the
K.sup.th frame is configured to carry a variable value
(C.sub.block.sub.--.sub.delta) obtained by subtracting the base
number from the block number of the client signal borne by
(K+n).sup.th frame for three times, and the receiving end can
determine that the block number of the client signal borne by the
(K+n).sup.th frame is
C.sub.block=C.sub.block.sub.--.sub.base+C.sub.block.sub.--.sub.delta
according to the C.sub.block.sub.--.sub.base and
C.sub.block.sub.--.sub.delta values carried by the C.sub.block
bytes of the K.sup.th frame.
[0058] It can be seen that, in the method for indicating the
C.sub.block value of the (K+n).sup.th frame to the receiving end by
using the base number value and the variable value, since the same
base number value is carried, the reliability of transmission is
ensured; in addition, since each frame carries the variable value
for three times, the reliability of transmission is further
ensured.
[0059] The mapping OH information of the (K+n).sup.th frame is sent
to the receiving end by using the K.sup.th frame. After receiving
the K.sup.th frame, the receiving end can determine the C.sub.block
value of the (K+n).sup.th frame, the size of the logically divided
sub-blocks of the OPUk payload area, a mapping manner and the like,
and thus can correctly demap the client signal borne by the
(K+n).sup.th frame.
[0060] It should be understood that, a part or all of the
indication information in the mapping OH information may be
indicated to the receiving end in a default manner. For example,
for OPUk units of different rates, the size of the logically
divided sub-blocks of the payload area may be corresponding to a
certain value by default, and the specific correspondence is as
shown in Table 2, but is not limited thereto.
TABLE-US-00002 TABLE 2 Sub-block Size (byte) OPUk/ODTUjk 1
OPU0/ODTU01/ODTU02/ODTU03/ODTU04 2 OPU1/ODTU12/ODTU13/ODTU14 8
OPU2/ODTU23/ODTU24 8 OPU2e/ODTU2e3/ODTU2e4 16 OPU3y/ODTU34 64
OPU4
[0061] It can be seen that, by using the indication through the
default correspondence between sub-block sizes and rate levels
shown in Table 2, the receiving end can directly determine the size
of the logically divided sub-blocks of the OPUk payload area
according to a rate level of the received OTN frame, and thus can
demap the client signal in combination with other indication
information.
[0062] Moreover, clock information and client signal information
may be respectively carried through different OH fields, and
mapping by using a granularity of a block does not affect the clock
performance.
[0063] It should be noted that, the above method for carrying the
mapping OH information by using the OPUk OH area is illustrated
based on an example only, but the present invention is not limited
thereto, and the mapping OH information of the (K+n).sup.th frame
may also be carried to the receiving end by using the OPUk OH area
of the K.sup.th frame through other methods.
[0064] In Step 403, sigma-delta calculation is performed by using
the C.sub.block value of the (K+n).sup.th frame, and the client
signal is mapped to corresponding sub-blocks of the OPUk payload
area of the (K+n).sup.th frame.
[0065] The sigma-delta calculation is performed by using the
acquired block number of the client signal to be borne by the
(K+n).sup.th frame, so a position distribution of the client signal
in the OPUk payload area can be obtained, and the client signal to
be borne by the (K+n).sup.th frame can be uniformly mapped to
corresponding sub-blocks of the OPUk payload area of the
(K+n).sup.th frame with an N-byte granularity, so that client
signal sub-blocks and stuff sub-blocks are uniformly distributed in
the OPUk payload area of the (K+n).sup.th frame.
[0066] The sigma-delta calculation is briefly illustrated in the
following.
[0067] If (i.times.C.sub.block)mod M<C.sub.block, the i.sup.th
sub-block is a client signal sub-block.
[0068] If (i.times.C.sub.block) mod M.gtoreq.C.sub.block, the
i.sup.th sub-block is a stuff sub-block, in which C.sub.block is
the block number of the borne client signal, and M is the total
number of the logically divided sub-blocks of the OPUk payload
area.
[0069] In the framing process, when a row/column counter indicates
that rows/columns processed in a current clock cycle are located or
partially located at the OPUk payload area, an adder/comparator
performs the sigma-delta calculation, and determines whether a
sub-block corresponding to the rows/columns processed in the
current clock cycle is a sub-block to which the client signal is
mapped, and if yes, uses the sub-block as a client signal sub-block
and the client signal is mapped to the sub-block; otherwise, uses
the sub-block as a stuff sub-block.
[0070] For example, it is assumed that the processing bit width of
the processor is 16*8=128 bits, the size of the logically divided
sub-blocks of the OPUk payload area of the (K+n).sup.th frame is
N=8 bytes, and the entire OPUk payload area is divided into M=1904
sub-blocks. When the row/column counter indicates that the
rows/columns processed in the current clock cycle are located in
the OPUk payload area, only an 11-bit adder/comparator needs to be
selected to perform sigma-delta calculation twice in the clock
cycle, so as to complete mapping of 2 sub-blocks (2*8 bytes). If a
decision granularity of a byte is used, a 14-bit adder/comparator
needs to be selected to perform sigma-delta calculation for 16
times, so as to complete mapping of 16 bytes.
[0071] For another example, assuming that the processing bit width
for the OPU4 is 64*8=512 bits, if the OPU4 payload area of the
(K+n).sup.th frame is logically divided into 238 sub-blocks each
having 64 bytes, only an 8-bit adder/comparator needs to select to
perform sigma-delta calculation once in a processor clock cycle, so
as to complete mapping of 1 sub-block (64 bytes). Similarly, if a
decision granularity of a byte is used, a 14-bit adder/comparator
needs to be selected to perform sigma-delta calculation for 64
times so as to complete mapping of 64 bytes.
[0072] It can be seen that, for high rate units such as OPU3y and
OPU4, the payload area may be logically divided into several
sub-blocks of 16 bytes, 32 bytes, or 64 bytes flexibly, and
sigma-delta calculation is performed by using a decision
granularity of a block, so that the mapping process can be greatly
simplified.
[0073] Optionally, several phase relations of stuff sub-blocks and
client signal sub-blocks in the OPUk payload area may also be
preset corresponding to the sub-block size of each type of logical
division of the OPUk payload area, and each phase relation is
corresponding to the block number of the client signal borne by the
OPUk payload area, so that when the client signal is mapped, the
client signal can be fixedly mapped to the client signal sub-blocks
of the OPUk payload area directly according to the preset phase
relations.
[0074] The mapping of the client signal through phase presetting of
stuff sub-blocks and client signal sub-blocks can greatly reduce
the decision and calculation amount, and simplify the mapping
process, thereby achieving flexible processing.
[0075] Further, the (K+n).sup.th frame is sent after the OH area
information of the (K+n).sup.th frame is generated.
[0076] Correspondingly, in an embodiment, the present invention
further provides a method for demapping a client signal.
[0077] Referring to FIG. 6, a method for demapping a client signal
according to the second embodiment of the present invention
specifically includes the following steps.
[0078] In Step 601, a receiving end acquires mapping OH information
of a (K+n).sup.th frame.
[0079] The receiving end can acquire the mapping OH information of
the (K+n).sup.th frame by demapping an OPUk OH area of a K.sup.th
frame. The acquired mapping OH information includes, but is not
limited to, indication information of a block number of a client
signal borne by a payload area, a size of logically divided
sub-blocks of the payload area, a mapping manner and the like.
[0080] In Step 602, the receiving end demaps the client signal
borne by the payload area of the (K+n).sup.th frame by using a
sigma-delta algorithm according to the mapping OH information of
the (K+n).sup.th frame.
[0081] Correspondingly, the receiving end may determine a mapping
manner of the (K+n).sup.th frame, the size of the logically divided
sub-blocks of the payload area, and the block number of the borne
client signal according to the mapping OH information. The
receiving end can determine a position distribution of the client
signal in the sub-blocks of the payload area by using the
sigma-delta algorithm according to the above information, that is,
determine the client signal sub-blocks and the stuff sub-blocks,
and thus can demap the client signal of the payload area to recover
the client signal according to the determined position
distribution.
[0082] It can be seen that, in this embodiment, the OPUk payload
area is logically divided into blocks flexibly, and when the client
signal is mapped, block mapping of the client signal is performed
by using a mapping decision granularity of a block, so that the
mapping process of the client signal is simplified, thereby meeting
requirements of multi-rate services.
[0083] Further, the OPUk payload area may be divided into blocks
flexibly through many different schemes.
Third Embodiment
[0084] FIG. 7 is a schematic structural view of an OPUk payload
area and an OPUk OH area according to a third embodiment of the
present invention. Referring to FIG. 7, in this embodiment, the
OPUk payload area is divided into a block region and an adjustment
region. The block region is logically divided into M sub-blocks
each having a size of N bytes, and the entire block region has a
size of M*N bytes.
[0085] It should be understood that, the size of the logically
divided sub-blocks of the OPUk block region may be arbitrary, that
is to say, N may be any value that is exactly divisible by the byte
number of the OPUk block region.
[0086] Preferably, the OPUk block region may be logically divided
into the sub-blocks according to a processing bit width of a
processor, and the size of the logically divided sub-blocks is a
submultiple of the processing bit width of the processor. For
example, assuming that the processing bit width of the processor is
16*8=128 bits, the size of the logically divided sub-blocks may be
16 bytes, 8 bytes, 4 bytes, 2 bytes, or 1 byte.
[0087] It should be noted that, this embodiment takes the 17.sup.th
to 3824.sup.th columns of the 1.sup.st to 4.sup.th rows and the
16.sup.th column of the 4.sup.th row of an OTN frame as an example
of the OPUk payload area for illustration, but is not limited
thereto, and the OPUk payload area may further include other
reserved bytes in the OPUk OH area and/or other OH bytes for
bearing the client signal.
[0088] It should be noted that, this embodiment takes the 16.sup.th
to 20.sup.th columns of the 4.sup.th row of the OTN frame as an
example of the adjustment region and other portions of the OPUk
payload area as an example of the block region for illustration,
but is not limited thereto, and the size ratio and positions of the
OPUk adjustment region and block region may be flexibly
adjusted.
[0089] Referring to FIG. 8, a method for mapping a client signal
according to the third embodiment of the present invention
specifically includes the following steps.
[0090] In Step 801, a block number and an adjustment byte number of
a client signal to be borne by a (K+n).sup.th frame are
acquired.
[0091] For example, the block number of the client signal to be
borne by the (K+n).sup.th frame may be determined according to the
bearer capability of the OTN frame and the size of the logically
divided sub-blocks of the OPUk block region of the (K+n).sup.th
frame, and the size of the data blocks is identical to the size of
the logically divided sub-blocks of the corresponding OPUk block
region, that is, N bytes.
[0092] A specific implementation may be as follows: a byte number
(represented by A in the following) of the client signal to be
borne by the (K+n).sup.th frame is determined first, the determined
byte number is divided by the size of the logically divided
sub-blocks of the OPUk block region, the result of exact division
can be taken as the block number (represented by
C.sub.block.sub.--.sub.base in the following) of the client signal
to be borne by the (K+n).sup.th frame, and the remainder can be
taken as the adjustment byte number (represented by C.sub.delta in
the following), in which the relation between A,
C.sub.block.sub.--.sub.base, N, and C.sub.delta is
A=C.sub.block.sub.--.sub.base*N+C.sub.delta. The (K+n).sup.th frame
needs to bear C.sub.block.sub.--.sub.base*N+C.sub.delta bytes of
the client signal, in which C.sub.block.sub.--.sub.base*N is not
greater than the byte number of the block region of the
(K+n).sup.th frame, and C.sub.delta is not greater than the byte
number of the adjustment region.
[0093] For example, assuming that the size of the logically divided
sub-blocks of the OPUk block region of the (K+n).sup.th frame is
N=4, and the determined byte number of the client signal to be
borne by the (K+n).sup.th frame is A=14408, it can be further
determined that the block number of the client signal to be borne
by the (K+n).sup.th frame is C.sub.block.sub.--.sub.base=3602, in
which A=C.sub.block.sub.--.sub.base*N+0, that is to say, the block
region of the (K+n).sup.th frame needs to bear C.sub.block*N=14408
bytes of the client signal, and the adjustment region needs to bear
0 bytes of the client signal.
[0094] For another example, assuming that the size of the logically
divided sub-blocks of the block region of the (K+n).sup.th frame is
N=4, and the determined byte number of the client signal to be
borne by the (K+n).sup.th frame is A=14407, it can be further
determined that the block number of the client signal to be borne
by the block region of the (K+n).sup.th frame is
C.sub.block.sub.--.sub.base=3601, in which
A=C.sub.block.sub.--.sub.base*N+3, that is to say, the block region
of the (K+n).sup.th frame needs to bear
C.sub.block.sub.--.sub.base*N=14404 bytes of the client signal, and
the adjustment region needs to bear the remaining 3 bytes of the
client signal.
[0095] In Step 802, mapping OH information is generated, and is
mapped to an OH area of the K.sup.th frame, in which the mapping OH
information includes indication information for indicating the
block number of the client signal to be borne by the block region
of the (K+n).sup.th frame, and indication information for
indicating the byte number of the client signal to be borne by the
adjustment region of the (K+n).sup.th frame.
[0096] The mapping OH information may include, but is not limited
to, indication information for indicating the size of the logically
divided sub-blocks of the OPUk block region of the (K+n).sup.th
frame, the block number of the client signal to be borne by the
OPUk block region of the (K+n).sup.th frame, the byte number of the
client signal to be borne by the OPUk adjustment region of the
(K+n).sup.th frame, a mapping manner of the (K+n).sup.th frame and
the like.
[0097] A specific implementation may be as follows: the mapping OH
information is mapped to an OPUk OH area of the K.sup.th frame. The
structure of the OPUk OH area may be as shown in FIG. 7. The OPUk
OH area is located at the 1.sup.st to 4.sup.th rows of the
15.sup.th column and the 1.sup.st to 3.sup.rd rows of the 16.sup.th
column of the OTN frame, and includes 4+3 bytes. The OPUk OH area
may be divided as follows, but is not limited thereto.
[0098] Three bytes of the 1.sup.st to 3.sup.rd rows of the
15.sup.th column of the OTN frame are reserved (RES) bytes, and 1
byte of the 4.sup.th row is a PSI byte. Assuming that a multiframe
period of the OTN frame is 256, PSI[0] may carry indication
information of a PT identifier, and in this embodiment, the
indication information carried by PSI[0] indicates a GMP mapping
manner; PSI[1] may carry indication information for indicating the
size of the logically divided sub-blocks of the OPUk block region,
and may be, for example, 0X04, indicating that the block size is 4
bytes; and PSI[2] to PSI[255] may serve as reserved bytes.
[0099] Three OH bytes of the 1.sup.st to 3.sup.rd rows of the
16.sup.th column of the OTN frame are C.sub.block bytes, as shown
in FIG. 7. The C.sub.block bytes are divided into a (3*5)-bit
C.sub.block.sub.--.sub.base field (block field) and a (3*3)-bit
C.sub.delta field (adjustment field), in which the block field of
the C.sub.block bytes of the K.sup.th frame carries indication
information for indicating the block number
(C.sub.block.sub.--.sub.base) of the client signal borne by the
OPUk block region of the (K+n).sup.th frame, and the adjustment
field carries indication information for indicating the byte number
(C.sub.delta) of the client signal borne by the OPUk adjustment
region of the (K+n).sup.th frame for three times. The receiving end
can determine the block number of the client signal borne by the
OPUk block region of the (K+n).sup.th frame and the byte number of
the client signal borne by the OPUk adjustment region of the
(K+n).sup.th frame according to the indication information carried
by the C.sub.block bytes of the K.sup.th frame.
[0100] The position and size of the adjustment region may be
default, or the corresponding indication information may be carried
to the receiving end through other OH bytes, which can be flexibly
selected.
[0101] For example, assuming that the block number of the client
signal to be borne by the block region of the (K+n).sup.th frame is
C.sub.block.sub.--.sub.base=3586, and the adjustment region needs
to bear C.sub.delta=3 bytes of the client signal, the block field
of the C.sub.block bytes of the K.sup.th frame carries a binary
code 000111000000010, and the adjustment field carries three
identical binary codes 011.
[0102] Moreover, clock information and client signal information
may be respectively carried through different OH fields, and
mapping by using a granularity of a block does not affect the clock
performance.
[0103] Optionally, similar to the second embodiment, a part or all
of the indication information in the mapping OH information may be
indicated to the receiving end in a default manner, for example, a
rate level of the OTN frame may be used to indicate the size of the
logically divided sub-blocks of the block region of the OPUk
payload area by default, which may be specifically as shown in
Table 2.
[0104] It should be noted that, the above method for carrying the
mapping OH information by using the OPUk OH area is illustrated by
way of example only, but the present invention is not limited
thereto, and the mapping OH information of the (K+n).sup.th frame
may also be carried to the receiving end by using the OPUk OH area
of the K.sup.th frame through other methods.
[0105] The mapping OH information of the (K+n).sup.th frame is sent
to the receiving end by using the K.sup.th frame. After receiving
the K.sup.th frame, the receiving end can determine the
C.sub.block.sub.--.sub.base value and C.sub.delta value of the
(K+n).sup.th frame, the size of the logically divided sub-blocks of
the block region of the OPUk payload area, a mapping manner and the
like, and thus can correctly demap the client signal borne by the
(K+n).sup.th frame.
[0106] In Step 803, sigma-delta calculation is performed by using
the C.sub.block.sub.--.sub.base value of the (K+n).sup.th frame,
and the client signal is mapped to corresponding sub-blocks of the
payload area of the (K+n).sup.th frame.
[0107] The sigma-delta calculation is performed by using the
acquired block number of the client signal to be borne by the
(K+n).sup.th frame, so a position distribution of the client signal
in the block region can be determined, and a part or all of the
client signal to be borne by the (K+n).sup.th frame can be
uniformly mapped to corresponding sub-blocks of the OPUk block
region of the (K+n).sup.th frame with an N-byte granularity.
[0108] Similarly, in the framing process, when a row/column counter
indicates that rows/columns processed in a current clock cycle are
located or partially located at the OPUk block region, an
adder/comparator performs sigma-delta calculation, and determines
whether a sub-block corresponding to the rows/columns processed in
the current clock cycle is a sub-block to which the client signal
is mapped, and if yes, uses the sub-block as a client signal
sub-block and maps the client signal; otherwise, uses the block as
a stuff sub-block.
[0109] For example, it is assumed that the processing bit width of
the processor is 16*8=128 bits, the OPUk block region of the
(K+n).sup.th frame is 15228 bytes, the adjustment region is 5
bytes, the size of the logically divided sub-blocks of the OPUk
block region of the (K+n).sup.th frame is N=4 bytes, and the entire
OPUk block region is divided into M=3807 sub-blocks. When the
row/column counter indicates that the rows/columns processed in the
current clock cycle are located in the OPUk block region, only a
12-bit adder/comparator needs to be selected to perform sigma-delta
calculation by using a decision granularity of a block for 4 times,
so as to complete mapping of 4 sub-blocks (4*4 bytes). If a
decision granularity of a byte is used, a 14-bit adder/comparator
needs to be selected to perform sigma-delta calculation for 16
times so as to complete mapping of 16 bytes. The OPUk adjustment
region bears C.sub.delta bytes of the client signal, and
C.sub.delta bytes of the client signal may be mapped to the
adjustment region according to an agreed rule, for example, from
left to right or from right to left.
[0110] Optionally, several position distribution relations of stuff
sub-blocks (sub-blocks for bearing a stuff signal) and client
signal sub-blocks (sub-blocks for bearing the client signal) in the
OPUk block region may also be preset corresponding to the sub-block
size of each type of logical division of the OPUk block region, and
each position distribution relation is corresponding to the block
number of the client signal borne by the OPUk block region, so that
when the client signal is mapped, the client signal can be fixedly
mapped to the client signal sub-blocks of the OPUk block region
directly according to the preset position distribution
relations.
[0111] The mapping of the client signal through presetting of the
position distribution of stuff sub-blocks and client signal
sub-blocks can greatly reduce the decision and calculation process,
and simplify the mapping process, thereby achieving flexible
processing.
[0112] Further, the (K+n).sup.th frame is sent after the OH area
information of the (K+n).sup.th frame is generated.
[0113] Correspondingly, in an embodiment, the present invention
further provides a method for demapping a client signal.
[0114] Referring to FIG. 9, a method for demapping a client signal
according to the third embodiment of the present invention
specifically includes the following steps.
[0115] In Step 901, a receiving end acquires mapping OH information
of a (K+n).sup.th frame.
[0116] The receiving end can acquire the mapping OH information of
the (K+n).sup.th frame by demapping an OPUk OH area of a K.sup.th
frame. The acquired mapping OH information includes, but is not
limited to, indication information of a block number of a client
signal borne by a block region, a size of logically divided
sub-blocks of the block region, a size of an adjustment region, a
byte number of the client signal borne by the adjustment region, a
mapping manner and the like.
[0117] In Step 902, the receiving end demaps the client signal
borne by the payload area of the (K+n).sup.th frame by using a
sigma-delta algorithm according to the mapping OH information of
the (K+n).sup.th frame.
[0118] Correspondingly, the receiving end may determine a mapping
manner of the (K+n).sup.th frame, the size of the logically divided
sub-blocks of the block region, the block number of the client
signal borne by the block region, the size of the adjustment
region, and the byte number of the client signal borne by the
adjustment region according to the mapping OH information. The
receiving end can determine a position distribution of the client
signal in the payload area by using a sigma-delta algorithm
according to the above information, and thus can demap the client
signal of the payload area to recover the client signal according
to the determined position distribution.
[0119] It can be seen that, in this embodiment, the OPUk payload
area is logically divided into sub-blocks flexibly, and when the
client signal is mapped, block mapping of the client signal is
performed by using a mapping decision granularity of a block, so
that the mapping process of the client signal is simplified,
thereby meeting requirements of multi-rate services.
[0120] Further, the OPUk payload area may be divided into a block
region and an adjustment region, and the OPUk block region is
flexibly divided into blocks, so that both block mapping and byte
mapping can be performed, thereby achieving higher service
adaptability, more flexible mapping process, and more diversified
solutions.
[0121] It should be understood that, the mapping and demapping
methods and devices described in the above embodiments are also
suitable for mapping an ODUj client signal to a payload area of
Optical channel Data Tributary Unit j to k (ODTUjk) and demapping
the ODUj client signal from the payload area of the ODTUjk.
[0122] For example, when an ODU2 signal is mapped to an ODTU24, a
block size of 8 bytes can be selected for mapping.
Fourth Embodiment
[0123] Correspondingly, in an embodiment, the present invention
further provides a device for mapping a client signal. Referring to
FIG. 10, a device for mapping a client signal according to a fourth
embodiment of the present invention includes a block number
calculating module 1010, a mapping control module 1020, and a
mapping module 1030.
[0124] The block number calculating module 1010 is configured to
calculate a block number of a client signal to be transported
according to a sub-block size of a payload area of an OPU or ODTU,
in which the payload area includes several sub-blocks having a size
of N bytes, and N is greater than or equal to 1.
[0125] The mapping control module 1020 is configured to generate a
control signal according to the block number of the client signal,
in which the control signal is configured to indicate a position
distribution of the client signal to be transported in sub-blocks
of the payload area.
[0126] The mapping module 1030 is configured to map the client
signal, to be transported, in a buffer 1040 to corresponding
sub-blocks of the payload area according to the control signal
generated by the mapping control module 1020.
[0127] In an application scenario, the mapping control module 1020
is specifically configured to perform sigma-delta calculation
according to the block number calculated by the block number
calculating module 1010 to generate a control signal, and the
control signal is configured to indicate the position distribution
of the client signal to be transported in the sub-blocks of the
payload area.
[0128] The mapping module 1030 reads client data from the buffer
1040 with an N-byte granularity according to the indication of a
row/column counter with regard to rows/columns processed in a
current clock cycle and under the control of the control signal,
and maps the client data to the corresponding sub-blocks of the
payload area.
[0129] In an application scenario, the mapping control module 1020
is further configured to generate mapping OH information, and the
mapping OH information includes indication information of the block
number of the client signal to be transported.
[0130] In an application scenario, the mapping module 1030 is
further configured to map the mapping OH information to an OH area
of the OPU or ODTU.
[0131] If the payload area includes an adjustment region and a
block region, and the block region includes several sub-blocks
having a size of N bytes, the mapping module 1030 is further
configured to map several bytes of the client signal in the buffer
to the adjustment region.
[0132] It should be understood that, the functions of the
functional modules of the device according to this embodiment may
be specifically implemented according to the method in the second
or third embodiment, and for the specific implementation process,
reference can be made to the relevant description in the second or
third embodiment, and the details will not be described herein
again.
Fifth Embodiment
[0133] Correspondingly, in an embodiment, the present invention
further provides a device for demapping a client signal. Referring
to FIG. 11, a device for demapping a client signal according to a
fifth embodiment of the present invention includes a demapping
control module 1110 and a demapping module 1120.
[0134] The demapping control module 1110 is configured to acquire a
block number of a client signal borne by a payload area of an OPU
or ODTU, and generate a control signal according to the block
number, in which the control signal is configured to indicate a
position distribution of the client signal in sub-blocks of the
payload area, the payload area includes several blocks having a
size of N bytes, and N is greater than or equal to 1.
[0135] The demapping module 1120 is configured to demap the client
signal borne by the payload area according to the control signal
generated by the demapping control module 1110.
[0136] In an application scenario, the demapping module 1120 demaps
the client signal borne by the corresponding sub-blocks of the
payload area from a buffer 1130 with an N-byte granularity
according to the indication of a row/column counter with regard to
rows/columns processed in a current clock cycle and under the
control of the control signal.
[0137] It should be understood that, the functions of the
functional modules of the device according to this embodiment may
be specifically implemented according to the method in the second
or third embodiment, and for the specific implementation process,
reference can be made to the relevant description in the second or
third embodiment, and the details will not be described herein
again.
[0138] It should be noted that, the above method embodiments are
expressed as a series of operations for ease of description;
however, it should be known to persons skilled in the art that the
present invention is not limited to the sequence of the operations
described, because some steps may be performed in other sequences
or concurrently according to the present invention. Furthermore, it
should also be known to persons skilled in the art that all the
embodiments described in the specification are preferred
embodiments, and the operations and modules involved may not be
necessary for the present invention.
[0139] In the above embodiments, the descriptions of the
embodiments place different emphasis on different aspects, and for
a part that is not detailed in an embodiment, reference can be made
to the relevant descriptions of other embodiments.
[0140] Based on the above, in the technical solutions adopted by
the embodiments of the present invention, the OPUk/ODTUjk payload
area is logically divided into blocks flexibly, and when the client
signal is mapped, block mapping of the client signal is performed
by using a mapping decision granularity of a block, so that the
mapping process of the client signal is simplified, thereby meeting
requirements of multi-rate services.
[0141] Further, the OPUk/ODTUjk payload area may be divided into a
block region and an adjustment region, and the OPUk/ODTUjk block
region is flexibly divided into blocks, so that both block mapping
and byte mapping can be performed, thereby achieving higher service
adaptability, more flexible mapping process, and more diversified
solutions.
[0142] Person having ordinary skill in the art may understand that
all or part of the steps of the method according to the embodiments
of the present invention may be implemented by a program
instructing relevant hardware. The program may be stored in a
computer readable storage medium. The storage medium may be a
magnetic disk, a Compact Disk Read-Only Memory (CD-ROM), a
Read-Only Memory (ROM), or a Random Access Memory (RAM).
[0143] A method and a device for mapping and demapping a client
signal provided by the present invention are introduced in detail
above, the principle and implementation of the present invention
are described herein through specific embodiments, and the
description of the embodiments are merely intended to make the
method and core idea of the present invention comprehensible.
Person having ordinary skill in the art can make variations and
modifications to the present invention in terms of the specific
implementations and application scopes according to the ideas of
the present invention. Therefore, the specification shall not be
construed as limitations to the present invention.
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