CN111082846B

CN111082846B - SERDES-based one-to-four repeater using method

Info

Publication number: CN111082846B
Application number: CN201911113147.0A
Authority: CN
Inventors: 谢海春; 杨梁
Original assignee: Tianjin Ronghui Microelectronics Technology Co ltd
Current assignee: Tianjin Ronghui Microelectronics Technology Co ltd
Priority date: 2019-11-14
Filing date: 2019-11-14
Publication date: 2022-03-11
Anticipated expiration: 2039-11-14
Also published as: CN111082846A

Abstract

The invention discloses a service method of a one-to-four repeater based on a SERDES, which comprises the following steps: s1, at the N-SERDES receiving end, after receiving 66b data from the N-SERDES, not decoding; s2, maintaining a 2bits TurnID (turn mark 00/01/10/11) in the QSB receiving direction, and carrying out 66/68b coding (private coding) on the TurnID and a 66b code; s3, dividing the 68b code into 4 17b codes, and respectively sending the 4b codes from 4 SERDES to the opposite end; s4, at the N-SERDES sending end, 4 17b codes are received from 4 channels respectively to form a 68b code; s5, carrying out private 68/66b decoding on the 68b code to obtain a 66b code and a turn ID of 2 bits. The invention can cover 90% (only 10% of the required length exceeds the scope of the invention) and the cost and the power consumption are far lower than 10Bast-T electric port and optical port, along with the popularization of 5G, the market expansion is more than 10 times, compared with 25/50G interface, the power consumption is lower than that of a direct connection cable, the stability of the system operation can be ensured, and the transmission distance can be improved to the maximum extent.

Description

SERDES-based one-to-four repeater using method

Technical Field

The invention relates to the technical field of signals, in particular to a one-to-four repeater using method based on a SERDES.

Background

And (3) SERDES: is an abbreviation of SERializer/DESerializer. It is a mainstream Time Division Multiplexing (TDM), point-to-point (P2P) serial communication technology. That is, at the transmitting end, the multi-path low-speed parallel signals are converted into high-speed serial signals, and finally, at the receiving end, the high-speed serial signals are converted into low-speed parallel signals again through a transmission medium (an optical cable or a copper wire). The point-to-point serial communication technology fully utilizes the channel capacity of a transmission medium, reduces the number of required transmission channels and device pins, and improves the transmission speed of signals, thereby greatly reducing the communication cost.

10G Base-T: the ieee802.3an standard specifies that the transmission cost and power consumption are quite high when the transmission is to be transmitted to 100 meters through 4 pairs of CAT6 stranded wires, and therefore most of market products are less than 30 meters.

PAM4(4Pulse Amplitude Modulation) signal is widely used for transmission of electrical signals or optical signals of 200G/400G interfaces as a hot signal transmission technology for high-speed signal interconnection in next-generation data centers. The traditional digital signal adopts NRZ (Non-Return-to-Zero) signal at most, namely, high and low signal levels are adopted to represent 1 and 0 information of a digital logic signal to be transmitted, and 1bit of logic information can be transmitted in each signal symbol period; the PAM signal may use more signal levels, so that more bits of logic information may be transmitted per symbol period. For example, in the case of PAM4 signal, which uses 4 different signal levels for signal transmission, each symbol period may represent 2bits of logic information (0, 1, 2, 3).

At present, the structure on the market is mainly a 10G interface and an 25/50G interface, the 10G interface has two interfaces of an optical port and an electric port at present, but the 10G interface has the problems of high power consumption and high cost and also has the problem that the 10G interface does not support industrial grade and military grade interfaces, the cost of 10Gbase-T can be accepted for industrial grade and military, but the power consumption of 10Baset-T is unacceptable, because the heat dissipation of military products is very difficult and the cost is high.

The 25/50G interface is mainly used for data centers, and for the data centers, power consumption is a very critical factor, because the power consumption not only consumes electricity but also causes unstable system operation.

The excessive cost of the optical module causes that the proportion of the optical module used by data is less than 5%, 95% of the optical module uses a direct connection cable, which causes the problems of high cost and large power consumption of an 25/50G interface, and therefore, a one-to-four repeater using method based on a SERDES is provided to solve the problems.

Disclosure of Invention

The invention aims to solve the defects in the prior art, and provides a one-to-four repeater using method based on a SERDES.

In order to achieve the purpose, the invention adopts the following technical scheme:

a one-to-four repeater using method based on SERDES comprises the following steps:

s1, at the N-SERDES receiving end, after receiving 66b data from the N-SERDES, not decoding;

s2, maintaining a 2bits TurnID (turn mark 00/01/10/11) in the QSB receiving direction, and carrying out 66/68b coding (private coding) on the TurnID and a 66b code;

s3, dividing the 68b code into 4 17b codes, and respectively sending the 4b codes from 4 SERDES to the opposite end;

s4, at the N-SERDES sending end, 4 17b codes are received from 4 channels respectively to form a 68b code;

s5, carrying out private 68/66b decoding on the 68b code to obtain a 66b code and a turn ID of 2 bits;

s6, the correct 66b code is sent from the N-SERDES.

Preferably, the turnID is used for out-of-order detection.

Preferably, according to S1, when the out-of-order detection mechanism is enabled, at the N-SERDES receiving end, every time one 66b code is received, the turn id is called as the transmit turn id, and the turn id is encoded by 66/68b, transmitted from 4 channels, and then the transmit turn id is increased by 1.

Preferably, according to S2, when the out-of-order detection mechanism is enabled, the transmit TurnID and the receive TurnID of each QSB are initialized to 0 at the time of QSB initialization.

Preferably, according to S4, when the out-of-order detection mechanism is enabled, 17b codes are received from four channels at the N-SERDES transmitting end, forming a 68b code, and obtaining 66b code and turn id through private decoding 68/66, if the turn id is not equal to the turn id of the receiving end or the 66b code is illegal, then it is considered that the transmission is wrong and error processing needs to be performed, otherwise, the turn id of the receiving end is increased by 1.

Preferably, the signal line is a V-by-one shielding signal line.

The invention can cover 90% and the cost and power consumption are far lower than 10Bast-T electric port and optical port, along with the popularization of 5G, the market expansion is more than 10 times, compared with 25/50G interface, the power consumption is lower than that of direct connection cable, the stability of system operation can be ensured, and the transmission distance can be improved to the maximum extent.

Drawings

FIG. 1 is a schematic input diagram of the present invention;

FIG. 2 is a schematic diagram of an internal structure of a signal line according to the present invention;

fig. 3 is a schematic diagram of the working principle of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments.

Referring to fig. 1-3, the present invention reduces the SNR of a high-speed SERDES data to 1/4 SERDES through 4 SERDES with frequencies reduced, and can transmit the data to a longer distance, and increases the transmission distance to the maximum extent through other LR techniques, including increasing the amplitude and increasing FEC, so as to achieve transmission with lower power consumption, lower cost and longer distance, and the working principle is as follows:

at the N-SERDES receiving end:

the first step is as follows: after receiving 66b data from the N-SERDES, decoding is not carried out;

the second step is that: maintaining a 2bits TurnID at the QSB receive side (round flag 00/01/10/11), and encoding the TurnID with 66b code 66/68b (private encoding);

the third step: dividing the 68b code into 4 17b codes, and respectively sending the 4 SERDES codes to the opposite end;

at the N-SERDES transmitting end:

the first step is as follows: respectively receiving 4 17b codes from 4 channels to form a 68b code;

the second step is that: private 68/66b decoding of the 68b code to obtain a 66b code and a turn ID of 2 bits;

and in a third step, the correct 66b code is transmitted from the N-SERDES.

TurnID is used for out of order detection, since the 66b encoding is continuous, no out of order occurs, but for greater robustness, the out of order detection mechanism is still enabled.

At the time of QSB initialization, both the transmit TurnID and the receive TurnID of each QSB are initialized to 0.

At the receiving end of the N-SERDES, every time a 66b code is received, the trunk ID is called as the transmitting TurnID, the TurnID is encoded by 66/68b and then transmitted from 4 channels, and then the transmitting TurnID is increased by 1.

At the N-SERDES transmitter, the 17b code is received from four channels, which are combined into one 68b code, and the 66b code and the turnID are obtained by private 68/66 decoding. If the turnID is not equal to the receiving end turnID or the 66b code is illegal, the transmission is considered erroneous. And error processing is needed, otherwise, the trunk ID of the receiving end is increased by 1.

In the invention, V-by-one shielding signal wires and flat wires are adopted, 210/25G can adopt RJ45 crystal heads and connectors, the length of a jumper can be customized, cables and modules can be fixed in pairs, the width of the dielectric layer is 10-50mil, and the thickness of the dielectric layer with the thickness of 1mil to 0.0254mm is modeled to ensure that the deviation within 10% of 100 ohm difference.

1N-SERDES, meaning SERDES on the Network side, the product must comply with the IEEE802.3 family of protocols.

We consider the common SERDES as an ADDC of one bit, which recognizes the signal as either 0 or 1 for one clock cycle. When the sampling period of the SERDES is too high, the SNR is reduced sharply, and the signal is difficult to transmit to the desired distance, so that the voltage is identified by using 8-bit sampled ADDC, and the bandwidth is provided by identifying the signal voltage as 00/01/10/11 2-bit signal in one clock period, which is called PAM 4. The SNR of PAM itself is low, but if the same speed is achieved, the frequency is doubled, the SNR is lower, and PAM4 is the main technical means for realizing 100/200/400G network interface.

In the case of N-SERDES, PAM4 technology is adopted in SERDES higher than 28G, and PAM4 technology is adopted in 50G N-SERDES in the present invention, according to the limitation of integrated circuit design.

The N-SERDES typically uses SR technology because interfacing with the network interface of the communication chip on board is short and therefore does not require very high SNR.

C-SERDES means Cable (Cable side) SERDES, which will use proprietary FEC techniques to achieve higher SNR for longer distances. C-SERDES does not comply with the IEEE standard because it is always interfacing with itself and does not need to interface with third parties, primarily considering power consumption and cost.

3QuadStackBufferQSB, (quad Stack Buffer) mainly solves the problem that the data received from the N-SERDES is sent to the opposite end through 4C-SERDES, and after the four C-SERDES at the opposite end are received, the data of the four C-SERDES are restored to the data of the N-SERDES to ensure the condition of no disorder, and the data are sent and removed through the N-SERDES at the opposite end.

To save power and cost, we use QSB transparent transmission technology. We did not design the MAC in the chip nor did we recover the 66/64b code from the N-SERDES. But a customized 68/66B code is performed on the basis of the original 66/64B code.

The invention is compared with a 10G photoelectric interface:

the invention is compared with a 25G photoelectric interface:

the invention is compared with a 50G photoelectric interface:

the chip parameters of the invention are as follows:

because the interface of the optical module is compatible, the voltage input of the module is 3.3V, the voltage in the module is reduced by using DC-DC (direct current-direct current), and then the voltage is stabilized by the LDO (low dropout regulator), so that the consideration of power consumption and performance is achieved.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims

1. A method for using a one-to-four repeater based on a SERDES (serial data encryption standard), which is characterized by comprising the following steps:

s2, maintaining a 2-bit trunID in the QSB receiving direction, marking the round 00/01/10/11, and carrying out 66/68b coding on the trunID and the 66b code;

s6, the correct 66b code is sent from the N-SERDES.

2. The SERDES-based one-in-four repeater use method of claim 1, wherein the turnID is used for out-of-order detection.

3. The method as claimed in claim 2, wherein the out-of-order detection mechanism is enabled by the N-SERDES receiving end, every time one 66b code is received, the trunID is called as the transmit trunID, the trunID is encoded by 66/68b and then transmitted from 4 channels, and then the transmit trunID is increased by 1.

4. The method as claimed in claim 2, wherein when the out-of-order detection mechanism is enabled and is initialized by the QSB, the transmit trunID and the receive turnID of each QSB are initialized to 0.

5. The method as claimed in claim 2, wherein the disorder detection mechanism is enabled by the N-SERDES transmitter, when receiving 17b codes from four channels, a 68b code is formed, and when obtaining 66b code and turn id by private 68/66 decoding, if turn id is not equal to turn id of the receiver or 66b code is illegal, the transmission is considered as wrong, and error processing is required, otherwise, the receiver trunID is increased by 1.