The present disclosure relates to communication systems, and more particularly to communicating data over a communication channel.
A transmitter can transmit a signal to a receiver over a communication channel such as a backplane. The signal can encode various data. If the communication channel is not perfect, then the signal received by the receiver may not be identical to the signal transited by the transmitter. For instance, the communication channel may have introduced noise into the signal. If the signal received by the receiver is distorted enough by the communication channel, then the data may not be recoverable by the receiver.
Embodiments of the present disclosure will now be described with reference to the attached drawings in which:
It should be understood at the outset that although illustrative implementations of one or more embodiments of the present disclosure are provided below, the disclosed systems and/or methods may be implemented using any number of techniques, whether currently known or in existence. The present disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated below, including the exemplary designs and implementations illustrated and described herein, but may be modified within the scope of the appended claims along with their full scope of equivalents.
This disclosure is related to communication systems involving transmission of OTN frames over a communication channel having multiple (optical or electrical) parallel lanes. In other words, this disclosure is related to communication over fiber optics (OTN optical modules) and/or communication over electrical/optical backplanes (OTN backplanes). Some examples include:
Provided is an apparatus and method for transmitting data over a communication channel having at least one physical lane for transmitting data. The apparatus includes, for each physical lane, allocation circuitry configured for allocating data in logical lanes corresponding to the physical lane. The apparatus also includes, for each physical lane, a multiplexer configured for bit-interleaving the data from the logical lanes corresponding to the physical lane into interleaved data for transmission over the physical lane. In accordance with an embodiment of the present disclosure, for each physical lane, the allocation circuitry is configured for allocating the data such that the interleaved data for transmission over the physical lane has clusters of sequential bits of the same symbol. Thus, upon transmission and reception by a receiver, any correlated errors affecting sequential bits may affect fewer symbols. Also provided is an apparatus and method for receiving data in a complementary manner.
Also provided is an apparatus and method for transmitting data over a communication channel having at least one physical lane for transmitting data. The apparatus includes, for each physical lane, allocation circuitry configured for allocating data in logical lanes corresponding to the physical lane. The apparatus also includes, for each physical lane, a multiplexer configured for bit-interleaving the data from the logical lanes corresponding to the physical lane into interleaved data for transmission over the physical lane. In accordance with an embodiment of the present disclosure, for each physical lane, the allocation circuitry is configured for mixing data portions without mixing any data portion containing FAS information. Thus, a receiver looking to find the FAS information in a data reception can find the FAS information in the same place that the FAS information would be expected had the allocation step not been executed. Also provided is an apparatus and method for receiving data in a complementary manner.
Other aspects and features of the present disclosure will become apparent, to those ordinarily skilled in the art, upon review of the following description of the specific embodiments of the invention.
Introduction
Referring first to
Each OTN framer device 111,121 (or switch device, FPGA, other circuitry, etc.) is configured to generate OTN frames, which can be transmitted across the backplane 130 thereby enabling communication between the OTN cards 110,120. One OTN framer device 111 can operate as a transmitter (i.e. encoding an FEC) with the other OTN framer device 121 operating as a receiver (i.e. decoding the FEC). Note that both OTN framer devices 111,121 may be capable of operating as a transmitter and a receiver. In some implementations, both OTN framer devices 111,121 contain high-speed interfaces (e.g. analog design) to serialize information at high speed rates (e.g. ˜28 Gbps). In some implementations, the OTN framer devices have a DFE (Decision Feedback Equalizer) that can be used to implement the high-speed interface for receiving data.
Referring now to
In specific implementations, the OTN frame is an OTU4 frame that is organized in 1020 16-byte groups. The first 16-byte group includes FAS (frame alignment signal) information, which includes information pertaining to alignment of the OTN frame. The first-byte group may also include MFAS (multi-frame alignment signal) information, which includes information pertaining to alignment of multiple OTN frames. The remaining 16-byte groups include data payload and may also include parity for FEC (Forward Error Correction) purposes. Specific details are provided in Annex C of ITU G.709.
Referring now to
One or more OTN frames may be transmitted and/or received over the OTN backplane 130 shown in
OTL4.4 for Transmitting OTN Frames
At step 4-1, each 16-byte group is distributed, round robin, to each of a plurality of logical lanes. In the illustrated example, it is assumed that there are 20 logical lanes. However, other implementations are possible in which there may be a different number of logical lanes. For 28 G physical lanes, the logical lanes are 5.6 G logical lanes. Since each frame has 1020 16-byte groups and there are 20 logical lanes, there will be 51 16-byte groups distributed to each logical lane.
In some implementations, step 4-1 includes lane rotation as shown in
Referring momentarily to
Note that the lane rotation described above with reference to
Referring back to
After allocating 4-2 the 16-byte groups in the logical lanes, there is a step of interleaving 4-3 the 16-byte groups from the logical lanes into the 28 G physical lanes. In the illustrated example, such interleaving is accomplished using four multiplexers 401,402,403,404. Each multiplexer 401,402,403,404 performs bit-interleaving of data from five logical lanes. While the interleaving is accomplished using four multiplexers 401,402,403,404, other implementations are possible in which there may be a different number of multiplexers.
In some implementations, the data provided to the OTL4.4 of
Referring now to
Referring now to
As previously described, data is transmitted by the OTL4.4 over the 28 G physical lanes for reception by an OTN framer device or a switch device as shown in
Optical transmission modulation schemes usually map the OTL4.L (physical or logical) lanes directly into the parallel bit streams used for the modulation. As an example, a DP-QPSK scheme usually maps each of the four 28 G electrical lanes into the I and Q components of each of the two polarizations (X and Y).
Modulation schemes often result in correlated errors. For example, DP-QPSK differential decoding leads to error pairs (and even quadruple errors with lower probability):
Referring now to
As shown in
Note that the aforementioned corruption issue is not unique to the OTL4.4 described with reference to
Referring now to
Referring now to
As shown in
The interaction between GFEC, the OTL4.4/OTL4.10 schemes (see
The combination of GFEC with the OTL4.4/OTL4.10 schemes also results in low tolerance to very small burst errors. This is an important problem because some hardware implementations of 100/280 electrical backplanes are based on a DFE (Decision Feedback Equalizer) for data recovery, and the DFE may generate small burst errors at its output.
The interaction between GFEC, OTL4.4/OTL4.10 and DFE impacts NGC (Net Coding Gain) of GFEC is shown in Table 3. These results are for a worst case scenario of zero skew among the different logical/electrical lanes.
In view of the foregoing, it can be seen that the interaction between GFEC and OTL4.L can have a significant impact on performance when exposed to correlated errors from advanced modulation schemes, DFE, etc. The interaction between the GFEC and the OTL4.L scheme occur because both schemes process OTN frames in groups of 16 bytes. This issue can be difficult to analyze for complex (multi-dimensional) FEC schemes as it depends on many different variables:
An example OTL that mitigates some or all of the foregoing issues will be described below with reference to
Another OTL for Transmitting OTN Frames
Referring now to
In some implementations, at step 11-1, each 16-byte group is distributed, round robin, to each of a plurality of logical lanes as similarly described above for
In contrast with the OTL shown in
The OTL of
In some implementations, the modified allocation of five rotated 16-byte groups to five logical lanes shown in
In some implementations, as described with reference to
G0[1]
G1[1]
G2[1]
G3[1]
G4[1]
G0[2]
G1[2]
G2[2]
G3[2]
G4[2]
G0[3]
G1[3]
G2[3]
G3[3]
G4[3]
G0[4]
G1[4]
G2[4]
G3[4]
G4[4]
G0[5]
G1[5]
G2[5]
G3[5]
G4[5]
G0[6]
G1[29]
G2[6]
G3[6]
G4[6]
G0[7]
G1[7]
G2[7]
G3[7]
G4[7]
G0[8]
G1[8]
G2[8]
G3[8]
G4[8]
G0[9]
G1[9]
G2[9]
G3[9]
G4[9]
G0[10]
G1[10]
G2[10]
G3[10]
G4[10]
G0[11]
G1[11]
G2[11]
G3[11]
G4[11]
G0[12]
G1[12]
G2[12]
G3[12]
G4[12]
G0[13]
G1[13]
G2[13]
G3[13]
G4[13]
G0[14]
G1[14]
G2[14]
G3[14]
G4[14]
G0[15]
G1[15]
G2[15]
G3[15]
G4[15]
G0[16]
G1[16]
G2[16]
G3[16]
G4[16]
G0[17]
G1[17]
G2[17]
G3[17]
G4[17]
G0[18]
G1[18]
G2[18]
G3[18]
G4[18]
G0[19]
G1[19]
G2[19]
G3[19]
G4[19]
G0[20]
G1[20]
G2[20]
G3[20]
G4[20]
G0[21]
G1[21]
G2[21]
G3[21]
G4[21]
G0[22]
G1[22]
G2[22]
G3[22]
G4[22]
G0[23]
G1[23]
G2[23]
G3[23]
G4[23]
G0[24]
G1[24]
G2[24]
G3[24]
G4[24]
G0[25]
G1[25]
G2[25]
G3[25]
G4[25]
G0[26]
G1[26]
G2[26]
G3[26]
G4[26]
G0[27]
G1[27]
G2[27]
G3[27]
G4[27]
G0[112]
G1[112]
G2[112]
G3[112]
G4[112]
G0[113]
G1[113]
G2[113]
G3[113]
G4[113]
G0[114]
G1[114]
G2[114]
G3[114]
G4[114]
G0[115]
G1[115]
G2[115]
G3[115]
G4[115]
G0[116]
G1[116]
G2[116]
G3[116]
G4[116]
G0[117]
G1[117]
G2[117]
G3[117]
G4[117]
G0[118]
G1[118]
G2[118]
G3[118]
G4[118]
G0[119]
G1[119]
G2[119]
G3[119]
G4[119]
G0[120]
G1[120]
G2[120]
G3[120]
G4[120]
G0[121]
G1[121]
G2[121]
G3[121]
G4[121]
G0[122]
G1[122]
G2[122]
G3[122]
G4[122]
G0[123]
G1[123]
G2[123]
G3[123]
G4[123]
G0[124]
G1[124]
G2[124]
G3[124]
G4[124]
G0[125]
G1[125]
G2[125]
G3[125]
G4[125]
G0[126]
G1[126]
G2[126]
G3[126]
G4[126]
G0[127]
G1[127]
G2[127]
G3[127]
G4[127]
G0[128]
G1[128]
G2[128]
G3[128]
G4[128]
rs1-s1[1]
rs1-s2[1]
rs1-s3[1]
rs1-s4[1]
rs1-s5[1]
rs1-s1[2]
rs1-s2[2]
rs1-s3[2]
rs1-s4[2]
rs1-s5[2]
rs1-s1[3]
rs1-s2[3]
rs1-s3[3]
rs1-s4[3]
rs1-s5[3]
rs1-s1[4]
rs1-s2[4]
rs1-s3[4]
rs1-s4[4]
rs1-s5[4]
rs1-s1[5]
rs1-s2[5]
rs1-s3[5]
rs1-s4[5]
rs1-s5[5]
rs1-s1[6]
rs1-s2[6]
rs1-s3[6]
rs1-s4[6]
rs1-s5[6]
rs1-s1[7]
rs1-s2[7]
rs1-s3[7]
rs1-s4[7]
rs1-s5[7]
rs1-s1[8]
rs1-s2[8]
rs1-s3[8]
rs1-s4[8]
rs1-s5[8]
rs2-s1[1]
rs2-s2[1]
rs2-s3[1]
rs2-s4[1]
rs2-s5[1]
rs2-s1[2]
rs2-s2[2]
rs2-s3[2]
rs2-s4[2]
rs2-s5[2]
rs2-s1[3]
rs2-s2[3]
rs2-s3[3]
rs2-s4[3]
rs2-s5[3]
rs2-s1[4]
rs2-s2[4]
rs2-s3[4]
rs2-s4[4]
rs2-s5[4]
rs2-s1[5]
rs2-s2[5]
rs2-s3[5]
rs2-s4[5]
rs2-s5[5]
rs2-s1[6]
rs2-s2[6]
rs2-s3[6]
rs2-s4[6]
rs2-s5[6]
rs2-s1[7]
rs2-s2[7]
rs2-s3[7]
rs2-s4[7]
rs2-s5[7]
rs2-s1[8]
rs2-s2[8]
rs2-s3[8]
rs2-s4[8]
rs2-s5[8]
rs3-s1[1]
rs3-s2[1]
rs3-s3[1]
rs3-s4[1]
rs3-s5[1]
rs3-s1[2]
rs3-s2[2]
rs3-s3[2]
rs3-s4[2]
rs3-s5[2]
rs3-s1[3]
rs3-s2[3]
rs3-s3[3]
rs3-s4[3]
rs3-s5[3]
rs3-s1[4]
rs3-s2[4]
rs3-s3[4]
rs3-s4[4]
rs3-s5[4]
rs3-s1[5]
rs3-s2[5]
rs3-s3[5]
rs3-s4[5]
rs3-s5[5]
rs3-s1[6]
rs3-s2[6]
rs3-s3[6]
rs3-s4[6]
rs3-s5[6]
rs3-s1[7]
rs3-s2[7]
rs3-s3[7]
rs3-s4[7]
rs3-s5[7]
rs3-s1[8]
rs3-s2[8]
rs3-s3[8]
rs3-s4[8]
rs3-s5[8]
rs4-s1[1]
rs4-s2[1]
rs4-s3[1]
rs4-s4[1]
rs4-s5[1]
rs4-s1[2]
rs4-s2[2]
rs4-s3[2]
rs4-s4[2]
rs4-s5[2]
rs4-s1[3]
rs4-s2[3]
rs4-s3[3]
rs4-s4[3]
rs4-s5[3]
rs14-s1[8]
rs14-s2[8]
rs14-s3[8]
rs14-s4[8]
rs14-s5[8]
rs15-s1[1]
rs15-s2[1]
rs15-s3[1]
rs15-s4[1]
rs15-s5[1]
rs15-s1[2]
rs15-s2[2]
rs15-s3[2]
rs15-s4[2]
rs15-s5[2]
rs15-s1[3]
rs15-s2[3]
rs15-s3[3]
rs15-s4[3]
rs15-s5[3]
rs15-s1[4]
rs15-s2[4]
rs15-s3[4]
rs15-s4[4]
rs15-s5[4]
rs15-s1[5]
rs15-s2[5]
rs15-s3[5]
rs15-s4[5]
rs15-s5[5]
rs15-s1[6]
rs15-s2[6]
rs15-s3[6]
rs15-s4[6]
rs15-s5[6]
rs15-s1[7]
rs15-s2[7]
rs15-s3[7]
rs15-s4[7]
rs15-s5[7]
rs15-s1[8]
rs15-s2[8]
rs15-s3[8]
rs15-s4[8]
rs15-s5[8]
rs16-s1[1]
rs16-s2[1]
rs16-s3[1]
rs16-s4[1]
rs16-s5[1]
rs16-s1[2]
rs16-s2[2]
rs16-
s3[2]
rs16-s4[2]
rs16-s5[2]
rs16
-
s1[3]
rs16-s2[3]
rs16-s3[3]
rs16-s4[3]
rs16-s5[3]
rs16-s1[4]
rs16-s2[4]
rs16-s3[4]
rs16-s4[4]
rs16-s5[4]
rs16-s1[5]
rs16-s2[5]
rs16-s3[5]
rs16-s4[5]
rs16-s5[5]
rs16-s1[6]
rs16-s2[6]
rs16-s3[6]
rs16-s4[6]
rs16-s5[6]
rs16-s1[7]
rs16-s2[7]
rs16-s3[7]
rs16-s4[7]
rs16-s5[7]
rs16-s1[8]
rs16-s2[8]
rs16-s3[8]
rs16-s4[8]
rs16-s5[8]
Note that the modified allocation described above with reference to
Another OTL for Transmitting OTN Frames
Referring now to
In some implementations, at step 14-1, each 16-byte group is distributed, round robin, to each of a plurality of logical lanes as similarly described above for
In contrast with the OTL shown in
The OTL of
In some implementations, the modified allocation of five rotated 16-byte groups to five logical lanes shown in
In some implementations, as described with reference to
G0[1]
G1[1]
G2[1]
G3[1]
G4[1]
G0[2]
G1[2]
G2[2]
G3[2]
G4[2]
G0[3]
G1[3]
G2[3]
G3[3]
G4[3]
G0[4]
G1[4]
G2[4]
G3[4]
G4[4]
G0[5]
G1[5]
G2[5]
G3[5]
G4[5]
G0[6]
G1[6]
G2[6]
G3[6]
G4[6]
G0[7]
G1[7]
G2[7]
G3[7]
G4[7]
G0[8]
G1[8]
G2[8]
G3[8]
G4[8]
G0[9]
G1[9]
G2[9]
G3[9]
G4[9]
G0[10]
G1[10]
G2[10]
G3[10]
G4[10]
G0[11]
G1[11]
G2[11]
G3[11]
G4[11]
G0[12]
G1[12]
G2[12]
G3[12]
G4[12]
G0[13]
G1[13]
G2[13]
G3[13]
G4[13]
G0[14]
G1[14]
G2[14]
G3[14]
G4[14]
G0[15]
G1[15]
G2[15]
G3[15]
G4[15]
G0[16]
G1[16]
G2[16]
G3[16]
G4[16]
G0[17]
G1[17]
G2[17]
G3[17]
G4[17]
G0[18]
G1[18]
G2[18]
G3[18]
G4[18]
G0[19]
G1[19]
G2[19]
G3[19]
G4[19]
G0[20]
G1[20]
G2[20]
G3[20]
G4[20]
G0[21]
G1[21]
G2[21]
G3[21]
G4[21]
G0[22]
G1[22]
G2[22]
G3[22]
G4[22]
G0[23]
G1[23]
G2[23]
G3[23]
G4[23]
G0[24]
G1[24]
G2[24]
G3[24]
G4[24]
G0[25]
G1[25]
G2[25]
G3[25]
G4[25]
G0[26]
G1[26]
G2[26]
G3[26]
G4[26]
G0[27]
G1[27]
G2[27]
G3[27]
G4[27]
G0[31]
G1[31]
G2[31]
G3[31]
G4[31]
G0[32]
G1[32]
G2[32]
G3[32]
G4[32]
G0[33]
G1[33]
G2[33]
G3[33]
G4[33]
G0[112]
G1[112]
G2[112]
G3[112]
G4[112]
G0[113]
G1[113]
G2[113]
G3[113]
G4[113]
G0[114]
G1[114]
G2[114]
G3[114]
G4[114]
G0[115]
G1[115]
G2[115]
G3[115]
G4[115]
G0[116]
G1[116]
G2[116]
G3[116]
G4[116]
G0[117]
G1[117]
G2[117]
G3[117]
G4[117]
G0[118]
G1[118]
G2[118]
G3[118]
G4[118]
G0[119]
G1[119]
G2[119]
G3[119]
G4[119]
G0[120]
G1[120]
G2[120]
G3[120]
G4[120]
G0[121]
G1[121]
G2[121]
G3[121]
G4[121]
G0[122]
G1[122]
G2[122]
G3[122]
G4[122]
G0[123]
G1[123]
G2[123]
G3[123]
G4[123]
G0[124]
G1[124]
G2[124]
G3[124]
G4[124]
G0[125]
G1[125]
G2[125]
G3[125]
G4[125]
G0[126]
G1[126]
G2[126]
G3[126]
G4[126]
G0[127]
G1[127]
G2[127]
G3[127]
G4[127]
G0[128]
G1[128]
G2[128]
G3[128]
G4[128]
rs1-s1[1]
rs1-s2[1]
rs1-s3[1]
rs1-s4[1]
rs1-s5[1]
rs1-s1[2]
rs1-s2[2]
rs1-s3[2]
rs1-s4[2]
rs1-s5[2]
rs1-s1[3]
rs1-s2[3]
rs1-s3[3]
rs1-s4[3]
rs1-s5[3]
rs1-s1[4]
rs1-s2[4]
rs1-s3[4]
rs1-s4[4]
rs1-s5[4]
rs1-s1[5]
rs1-s2[5]
rs1-s3[5]
rs1-s4[5]
rs1-s5[5]
rs1-s1[6]
rs1-s2[6]
rs1-s3[6]
rs1-s4[6]
rs1-s5[6]
rs1-s1[7]
rs1-s2[7]
rs1-s3[7]
rs1-s4[7]
rs1-s5[7]
rs1-s1[8]
rs1-s2[8]
rs1-s3[8]
rs1-s4[8]
rs1-s5[8]
rs2-s1[1]
rs2-s2[1]
rs2-s3[1]
rs2-s4[1]
rs2-s5[1]
rs2-s1[2]
rs2-s2[2]
rs2-s3[2]
rs2-s4[2]
rs2-s5[2]
rs2-s1[3]
rs2-s2[3]
rs2-s3[3]
rs2-s4[3]
rs2-s5[3]
rs2-s1[4]
rs2-s2[4]
rs2-s3[4]
rs2-s4[4]
rs2-s5[4]
rs2-s1[5]
rs2-s2[5]
rs2-s3[5]
rs2-s4[5]
rs2-s5[5]
rs2-s1[6]
rs2-s2[6]
rs2-s3[6]
rs2-s4[6]
rs2-s5[6]
rs2-s1[7]
rs2-s2[7]
rs2-s3[7]
rs2-s4[7]
rs2-s5[7]
rs2-
s1[8]
rs2-s2[8]
rs2-s3[8]
rs2-s4[8]
rs2-s5[8]
rs3-s1[1]
rs3-s2[1]
rs3-s3[1]
rs3-s4[1]
rs3-s5[1]
rs3-s1[2]
rs3-s2[2]
rs3-s3[2]
rs3-s4[2]
rs3-s5[2]
rs3-s1[3]
rs3-s2[3]
rs3-s3[3]
rs3-s4[3]
rs3-s5[3]
rs3-s1[4]
rs3-s2[4]
rs3-s3[4]
rs3-s4[4]
rs3-s5[4]
rs3-s1[5]
rs3-s2[5]
rs3-s3[5]
rs3-s4[5]
rs3-s5[5]
rs3-s1[6]
rs3-s2[6]
rs3-s3[6]
rs3-s4[6]
rs3-s5[6]
rs3-s1[7]
rs3-s2[7]
rs3-s3[7]
rs3-s4[7]
rs3-s5[7]
rs3-s1[8]
rs3-s2[8]
rs3-s3[8]
rs3-s4[8]
rs3-s5[8]
rs4-s1[1]
rs4-s2[1]
rs4-s3[1]
rs4-s4[1]
rs4-s5[1]
rs4-s1[2]
rs4-s2[2]
rs4-s3[2]
rs4-s4[2]
rs4-s5[2]
rs4-s1[3]
rs4-s2[3]
rs4-s3[3]
rs4-s4[3]
rs4-s5[3]
rs4-s1[7]
rs4-s2[7]
rs4-s3[7]
rs4-s4[7]
rs4-s5[7]
rs4-s1[8]
rs4-s2[8]
rs4-s3[8]
rs4-s4[8]
rs4-s5[8]
rs5-s1[1]
rs5-s2[1]
rs5-s3[1]
rs5-s4[1]
rs5-s5[1]
rs15-s2[3]
rs15-s3[3]
rs15-s4[3]
rs15-s5[3]
rs15-s1[4]
rs15-s2[4]
rs15-s3[4]
rs15-s4[4]
rs15-s5[4]
rs15-s1[5]
rs15-s2[5]
rs15-s3[5]
rs15-s4[5]
rs15-s5[5]
rs15-s1[6]
rs15-s2[6]
rs15-s3[6]
rs15-s4[6]
rs15-s5[6]
rs15-s1[7]
rs15-s2[7]
rs15-s3[7]
rs15-s4[7]
rs15-s5[7]
rs15-s1[8]
rs15-s2[8]
rs15-s3[8]
rs15-s4[8]
rs15-s5[8]
rs16-s1[1]
rs16-s2[1]
rs16-s3[1]
rs16-s4[1]
rs16-
s5[1]
rs16-s1[2]
rs16-s2[2]
rs16-s3[2]
rs16-s4[2]
rs16-s5[2]
rs16-s1[3]
rs16-s2[3]
rs16-s3[3]
rs16-s4[3]
rs16-s5[3]
rs16-s1[4]
rs16-s2[4]
rs16-s3[4]
rs16-s4[4]
rs16-s5[4]
rs16-s1[5]
rs16-s2[5]
rs16-s3[5]
rs16-s4[5]
rs16-s5[5]
rs16-s1[6]
rs16-s2[6]
rs16-s3[6]
rs16-s4[6]
rs16-s5[6]
rs16-s1[7]
rs16-s2[7]
rs16-s3[7]
rs16-s4[7]
rs16-s5[7]
rs16-s1[8]
rs16-s2[8]
rs16-s3[8]
rs16-s4[8]
rs16-s5[8]
Although there has been a focus on OTL 4.4 (i.e. OTU4 frames over four 28 G physical lanes), as noted above, other OTLs are possible in which there may be a different number of physical and logical lanes, and/or the physical and logical lanes may be rated to a speed different from that described. More generally, any suitable implementation in which data for transmission is at least partially clustered with sequential bits belonging to the same symbol is possible and is within the scope of this disclosure. Additionally, or alternatively, any suitable implementation in which data portions are mixed without mixing any data portion containing FAS information is possible and is within the scope of this disclosure.
OTL for Receiving OTN Frames
The OTLs described above with reference to
Note that the de-interleaved data would include clusters of sequential bits of different symbols due to the demultiplexer performing the bit de-interleaving of data. However, according to an embodiment of this disclosure, recovery circuitry recovers the data by mixing the de-interleaved data in order to achieve contiguous bits for each symbol. Thus, the original OTN frames can be recovered. Additionally, or alternatively, the recovery circuitry mixes the de-interleaved data without mixing any data portion containing FAS information, as the FAS information should not be mixed if its location has not been manipulated by the transmitting OTL.
In some implementations, the recovery circuitry is configured for mixing the de-interleaved data as a function of where the FAS information is located. Such mixing may for example be complementary to the allocation described above with reference to
Clauses
Additional aspects are defined by the following clauses:
Clause 1. A method for transmitting data over a communication channel having at least one physical lane for transmitting data, the method comprising:
for each physical lane, allocating data in logical lanes corresponding to the physical lane; and
for each physical lane, bit-interleaving the data from the logical lanes corresponding to the physical lane into interleaved data for transmission over the physical lane;
wherein, for each physical lane, the allocating is executed such that the interleaved data for transmission over the physical lane has clusters of sequential bits of a same symbol.
Clause 2. The method of Clause 1, wherein the method is for transmitting data frames each having a plurality of data portions, each data portion comprising at least one symbol, the method further comprising:
initially distributing each data portion in round robin to one of the logical lanes;
wherein, for each physical lane, the allocating is subsequently executed by mixing the data portions such that the interleaved data for transmission over the physical lane has clusters of sequential bits of a same symbol.
Clause 3. The method of Clause 2, comprising:
performing lane rotation on each frame boundary such that sequential frames differ in terms of how the data portions are distributed to the logical lanes.
Clause 4. The method of Clause 2 or Clause 3, comprising:
for each physical lane, mixing the data portions without mixing any data portion containing FAS (Frame Alignment Signal) information.
Clause 5. The method of Clause 4, comprising:
mixing the data portions as a function of where the FAS information is located.
Clause 6. The method of Clause 4, comprising:
for each physical lane, reducing occurrence of sequential bits of different symbols in the interleaved data for transmission without manipulating placement of any bits corresponding to the FAS information.
Clause 7. The method of any one of Clause 2 to Clause 6, wherein the communication channel has four physical lanes for transmitting data, the method comprising:
distributing each data portion in round robin to one of twenty logical lanes, the twenty logical lanes comprising four sets of five logical lanes with each set corresponding to a respective one of the physical lanes;
for each physical lane, bit-interleaving data from the five logical lanes corresponding to the physical lane.
Clause 8. The method of Clause 7, comprising transmitting data frames having 1020 16-byte data portions.
Clause 9. The method of Clause 8, comprising:
for each physical lane, allocating the data in the five logical lanes corresponding to the physical lane in accordance with Table 4, column “OTL4.4 of
Clause 10. The method of Clause 8, comprising:
for each physical lane, allocating the data in the five logical lanes corresponding to the physical lane in accordance with Table 6, column “OTL4.4 of
Clause 11. The method of any one of Clause 2 to Clause 6, wherein the communication channel has ten physical lanes for transmitting data, the method comprising:
distributing each data portion in round robin to one of twenty logical lanes, the twenty logical lanes comprising ten sets of two logical lanes with each set corresponding to a respective one of the physical lanes;
for each physical lane, bit-interleaving data from the two logical lanes corresponding to the physical lane.
Clause 12. The method of Clause 11, comprising transmitting data frames having 1020 16-byte data portions.
Additional aspects are defined by the following clauses:
Clause 13. A method for receiving data over a communication channel having at least one physical lane for receiving data, the method comprising:
for each physical lane, bit de-interleaving data from the physical lane to logical lanes corresponding to the physical lane thereby generating de-interleaved data in each logical lane, wherein the de-interleaved data has clusters of sequential bits of different symbols;
recovering the data by mixing the de-interleaved data in order to achieve contiguous bits for each symbol.
Clause 14. The method of Clause 13, comprising:
identifying each logical lane by using LLM (Logical Lane Marker) information; and
deskewing and reordering the logical lanes for reassembling an original frame.
Clause 15. The method of Clause 13 or Clause 14, wherein the communication channel has four physical lanes for receiving data, and wherein the logical lanes comprises four sets of five logical lanes with each set corresponding to a respective one of the physical lanes.
Additional aspects are defined by the following clauses:
Clause 16. A chip comprising an apparatus configured for implementing the method of any one of Clause 1 to Clause 12 for transmitting data over physical lanes of an OTN backplane.
Clause 17. The chip of Clause 16, further comprising an apparatus configured for implementing the method of any one of Clause 13 to Clause 15 for receiving data over the physical lanes of the OTN backplane.
Clause 18. The chip of Clause 16 or Clause 17, wherein the chip is an electrical chip.
Additional aspects are defined by the following clauses:
Clause 19. A method for transmitting data over a communication channel having at least one physical lane for transmitting data, the method comprising:
for each physical lane, allocating data in logical lanes corresponding to the physical lane; and
for each physical lane, bit-interleaving the data from the logical lanes corresponding to the physical lane into interleaved data for transmission over the physical lane;
wherein, for each physical lane, the allocating is executed by mixing data portions without mixing any data portion containing FAS (Frame Alignment Signal) information.
Clause 20. The method of Clause 19, comprising mixing data portions as a function of where the FAS information is located.
Additional aspects are defined by the following clauses:
Clause 21. A method for receiving data over a communication channel having at least one physical lane for receiving data, the method comprising:
for each physical lane, bit de-interleaving data from the physical lane to logical lanes corresponding to the physical lane thereby generating de-interleaved data in each logical lane;
recovering the data by mixing the de-interleaved data without mixing any data portion containing FAS (Frame Alignment Signal) information.
Clause 22. The method of Clause 19, comprising mixing the de-interleaved data as a function of where the FAS information is located.
Additional aspects are defined by the following clauses:
Clause 23. A chip comprising an apparatus configured for implementing the method of Clause 19 or Clause 20 for transmitting data over physical lanes of an OTN backplane.
Clause 24. The chip of Clause 23, further comprising an apparatus configured for implementing the method of Clause 21 or Clause 22 for receiving data over the physical lanes of the OTN backplane.
Clause 25. The chip of Clause 23 or Clause 24, wherein the chip is an electrical chip.
Numerous modifications and variations of the present disclosure are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the present disclosure may be practised otherwise than as specifically described herein.
This application claims priority from U.S. Provisional Patent Application Ser. No. 61/841,703 filed Jul. 1, 2013, the entire disclosure of which is incorporated by reference.
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Number | Date | Country | |
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20150003827 A1 | Jan 2015 | US |
Number | Date | Country | |
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61841703 | Jul 2013 | US |