Multidrop network system and network device

A multidrop network system includes N network devices including a master device and a plurality of slave devices. The N network devices synchronize their respective time zones in a synchronization phase, then jointly perform equalizer coefficient training in a training phase, and then obtain their respective transmission opportunities in turn in a data transmission phase. Each network device includes a channel equalizer trained in the training phase and used for processing data in the data transmission phase. In the training phase, the master device sends out a training notification to request the slave devices to enter the training phase; the master device performs the equalizer coefficient training after it transmits the training notification, and the slave devices perform the equalizer coefficient training after they receive the training notification. After the completion of the equalizer coefficient training, the master device sends out a beacon to start the data transmission phase.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to a network system and a network device, especially to a multidrop network system and a network device of the multidrop network system.

2. Description of Related Art

Based on the IEEE 802.3cg standard, a physical layer collision avoidance (PLCA) multidrop network operates no faster than 10 Mbps. If one would like to improve this network speed, she/he has to consider channel effects and tackle the problems of Intersymbol Interference (ISI). The influences of the channel effects and ISI on a reception signal can be mitigated if a channel equalizer of a receiver is well trained. Although equalizer training is found in some standards (e.g., IEEE 802.3bw and IEEE 802.3 bp) for this technical field, these standards merely define ways to train channel equalizer coefficients under a peer-to-peer transmission configuration, and these ways are not workable to a multidrop network system.

SUMMARY OF THE INVENTION

An object of the present disclosure is to disclose a multidrop network system and a network device as improvements over the prior art.

An embodiment of the multidrop network system of the present disclosure includes N network devices, wherein the N is an integer equal to or greater than two. The N network devices include a master device and (N−1) slave device(s). Each of the N network devices has an identification code as identification in the multidrop network system and thus the N network devices having N identification codes in total. The N network devices synchronize their respective time zones in a synchronization phase. K network devices of the N network devices jointly perform equalizer coefficient training in a training phase, wherein the K is an integer equal to or greater than two, and the K is not greater than the N. The N network devices obtain their respective transmission opportunities in turn according to the N identification codes in a data transmission phase.

In regard to the above embodiment, the K network devices include the master device and (K−1) slave device(s), and each of the K network devices includes a channel equalizer that is trained in the training phase and used for processing data in the data transmission phase. In the synchronization phase, the master device transmits a beacon to the (N−1) slave device(s) to synchronize the time zone of the master device with the time zone(s) of the (N−1) slave device(s) before the start of each round of data transmission of the N network devices. In the training phase, the master device sends out a training notification to request the (K−1) slave device(s) to enter the training phase and then performs the equalizer coefficient training. The (K−1) slave device(s) perform(s) the equalizer coefficient training after the (K−1) slave device(s) receive(s) the training notification.

An embodiment of the network device of the present disclosure is a master device among N network devices of a multidrop network system, wherein the N is an integer equal to or greater than two. The N network devices include the master device and (N−1) slave device(s). The N network devices synchronize their respective time zones in a synchronization phase. K network devices of the N network devices jointly perform equalizer coefficient training in a training phase, wherein the K is an integer equal to or greater than two, but is not greater than the N. The N network devices obtain their respective transmission opportunities in turn in a data transmission phase.

In regard to the above embodiment, the K network devices include the master device and (K−1) slave device(s). In the synchronization phase, the master device transmits a beacon to the (N−1) slave device(s) to synchronize the time zone of the master device with the time zone(s) of the (N−1) slave device(s) before the start of each round of data transmission of the N network devices. In the training phase, the master device sends out a training notification to request the (K−1) slave device(s) to enter the training phase and then performs the equalizer coefficient training according to a training signal from each of the (K−1) slave device(s) and an original pattern of the training signal.

Another embodiment of the network device of the present disclosure is a first slave device among N network devices of a multidrop network system, wherein the N is an integer equal to or greater than two. The N network devices include a master device and (N−1) slave device(s). The N network devices synchronize their respective time zones in a synchronization phase. K network devices of the N network devices jointly perform equalizer coefficient training in a training phase, wherein the K is an integer equal to or greater than two, but is not greater than the N. The N network devices obtain their respective transmission opportunities in turn in a data transmission phase.

In regard to the above embodiment, the K network devices include the master device and (K−1) slave device(s), and the (K−1) slave device(s) include(s) the first slave device and (K−2) slave device(s). In the synchronization phase, the first slave device receives a beacon from the master device to synchronize the time zone of the first slave device with the time zone of the master device before the start of each round of data transmission of the N network devices. In the training phase, the first slave device receives a training notification from the master device to enter the training phase and then performs the equalizer coefficient training according to a training signal from each of the master device and the (K−2) slave device(s) and according to an original pattern of the training signal.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present specification discloses a multidrop network system and a network device of the multidrop network system. The multidrop network system and network device can perform channel equalizer coefficient training under a multidrop network configuration to improve the network speed. The background knowledge of a multidrop network system is found in the IEEE 802.3cg standard, and the background knowledge of channel equalizer coefficient training is found in the IEEE 802.3bw standard and IEEE 802.3 bp standard.

FIG.1shows an embodiment of the multidrop network system of the present disclosure. The multidrop network system100ofFIG.1includes N network devices, that is to say N nodes. The N is an integer equal to or greater than two. The N network devices exchange data through a physical transmission medium102(e.g., twisted pair cable or optical cable) and include a master device110and (N−1) slave device(s)120. Each of the N network devices has an identification code (IDC) as identification in the multidrop network system100and thus the N network devices have N IDCs (e.g., 0, 1, 2, . . . , (N−2), and (N−1)) in total. The N network devices obtain their respective transmission opportunities in turn according to the N IDCs in each round of data transmission of the multidrop network system100. Since ways to obtain transmission opportunities fall beyond the scope of the present disclosure and are not limitations on the present invention, the description of these ways is omitted here. Those having ordinary skill in the art can refer to the US patent application publication of publication number US 2019/0230705 A1 to learn how the N network devices obtain their respective transmission opportunities in turn according to the N IDCs.

In regard to the embodiment ofFIG.1, the N network devices synchronize their respective time zones in a synchronization phase; K network devices of the N network devices jointly perform equalizer coefficient training in a training phase, wherein the K is an integer equal to or greater than two, and the K is not greater than the N; and the N network devices obtain their respective transmission opportunities in turn according to the N IDCs in a data transmission phase.FIG.2shows the flow of the synchronization phase210, the training phase220, and the data transmission phase230. It is noted that if the K is not equal to the N, the N network devices include the K network devices (e.g., devices incorporating the present invention) and the other (N−K) network device(s) (e.g., devices without the present invention); the (N−K) network device(s) do(es) not perform the equalizer coefficient training in the training phase; and the (N−K) network device(s) may be incapable of recognizing a training notification as mentioned in the following paragraph and may not respond to the training notification. It is also noted that the K network devices include the master device110and (K−1) slave device(s)120, and each of the K network devices includes a channel equalizer that is trained in the training phase and used for processing data in the data transmission phase.

In regard to the embodiment ofFIG.1, in the synchronization phase the master device110transmits a beacon to all the slave device(s)120to synchronize the time zone of the master device110with the time zone(s) of these slave device(s)120before each round of data transmission of the N network devices begins; and the above-mentioned synchronization can be realized with a known/self-developed means (e.g., every network device configured to reset its counter/timer according to the beacon). In the training phase, the master device110sends out the training notification to request the (K−1) slave device(s)120to enter the training phase. The master device110performs the equalizer coefficient training after it sends out the training notification; and the (K−1) slave device(s)120receive(s) the training notification and then perform(s) the equalizer coefficient training. After M round(s) of the equalizer coefficient training (hereinafter referred to as M round(s) of training), the master device110transmits the beacon to all the slave device(s)120to start the data transmission phase, wherein the M is a fixed/unfixed positive integer.

In an exemplary implementation, the M is a fixed positive integer, which means that the master device110transmits the beacon to all the slave device(s)120to start the data transmission phase after the M round(s) of training even though some of the K network devices may not finish the equalizer coefficient training yet.

In an exemplary implementation, the M is an unfixed positive integer. Each of the (K−1) slave device(s)120sends out a training-completion signal in at least one round of the M round(s) of training to announce its completion of the equalizer coefficient training. The last device to finish the equalizer coefficient training among the K network devices (i.e., the master device110and the (K−1) slave device(s)120) finishes the equalizer coefficient training in the Mthround (i.e., the last round) of the M round(s) of training; in other words, the value of the M is determined according to the time when all of the K network devices finish the equalizer coefficient training. After the master device110finishes the equalizer coefficient training and receives the training-completion signal from each of the (K−1) slave device(s)120, the master device110transmits the beacon to all the slave device(s)120to start the data transmission phase.

In regard toFIGS.1-2, after the master device110sends out the training notification, the K network devices perform the M round(s) of training. The K network devices send out K training signals in turn (e.g., the K network devices configured to send their respective training signals according to their respective IDCs) in an Xthround of training among the M round(s) of training, wherein the X is a positive integer not greater than the M. Each of the K network devices receives (K−1) training signal(s) from the other (K−1) network device(s) in the Xthround of training and performs the equalizer coefficient training according to the (K−1) training signal(s) and original pattern(s) of the (K−1) training signal(s). The equalizer coefficient training can be realized with a known/self-developed means such as those mentioned in the IEEE 802.3bw standard and/or the IEEE 802.3 bp standard. For example, the master device110receives the training signals from all the slave device(s)120in turn; upon receiving a training signal of a slave device120, the master device110compares the training signal with the original pattern of the training signal to obtain a comparison result, then adjusts one or more channel equalizer coefficient(s) of the master device110according to the comparison result, and stores the coefficient(s) that are suitable for receiving the signal from the slave device120. The way to perform the equalizer coefficient training for each slave device120can be the same as or derived from the above-mentioned example. In an exemplary implementation, the K training signals are the same before distortion, and the original patterns of the K training signals are the same and stored in the K network devices in advance for comparison; however, the present invention is not limited to the above features.

In regard toFIGS.1-2, since the transmission environment could change over time, each of the K network devices in the data transmission phase can request the multidrop network system100to return to the training phase and perform the equalizer coefficient training again. In an exemplary implementation, the master device110sends out the training notification again in the data transmission phase to request the K network devices to return to the training phase. In an exemplary implementation, one of the (K−1) slave device(s)120sends out a retraining request in the data transmission phase to request the master device110to send out the training notification so as to request the K network devices to return to the training phase. In an exemplary implementation, the master device110receives the retraining request in a round of data transmission and sends out the training notification after this round of data transmission finishes. In an exemplary implementation, one of the (K−1) slave device(s)120sends out the retraining request in a round of data transmission while the other (K−2) slave device(s) remain(s) silent after it/they receive(s) the retraining request so that the master device110can immediately send out the training notification in response to the retraining request before the end of this round of data transmission.

Each network device (i.e., the master device100or any slave device120) of the multidrop network system100inFIG.1can be implemented independently. Since those having ordinary skill in the art can appreciate the detail and modification of each network device of the multidrop network system100through the description of the embodiments ofFIGS.1-2, repeated and redundant description is omitted here.

It should be noted that people of ordinary skill in the art can selectively use some or all of the features of any embodiment in this specification or selectively use some or all of the features of multiple embodiments in this specification to implement the present invention as long as such implementation is practicable; in other words, the present invention can be carried out flexibly in accordance with the present disclosure.

To sum up, the multidrop network system and network device of the present disclosure can perform channel equalizer coefficient training under a multidrop network configuration to improve the network speed.