CN115347994A - Method, device, medium, wireless access device and system for in-network state feedback - Google Patents
Method, device, medium, wireless access device and system for in-network state feedback Download PDFInfo
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Abstract
The invention provides an in-network state feedback method, an in-network state feedback device, an in-network state feedback medium, wireless access equipment and an in-network state feedback system. An in-network state feedback method is applied to wireless access equipment and comprises the following steps: performing delay estimation on each downlink data packet arriving at the wireless access device; calculating a delay increment between adjacent downlink data packets based on the estimated delay and maintaining a delay profile of the ACK packets fed back by the uplink based on the delay increment; when the ACK packet arrives at the wireless access device, an adaptive out-of-band feedback signal control mechanism is utilized to delay the transmission of the ACK packet. The invention solves the problems of weak network and broken network from the communication server to the client.
Description
Technical Field
The present invention relates to the field of network real-time communication technologies, and in particular, to an intra-network state feedback method, apparatus, medium, wireless access device, and system.
Background
Nowadays, various Real-Time Communication (RTC) services have bright commercial prospects and great development potential due to their wide use in daily life. Common real-time communication services comprise video conferences, cloud games, virtual reality and the like, a common mode is that a server side sends real-time video frames to a client side, the real-time performance is a prominent advantage, the pictures can enhance interaction inductance and experience, and online communication of users is facilitated. At present, real-time audio and video services have two important trends, namely that the user scale of various services is continuously increased due to the low delay requirement of the user, and the business mode of the internet network audio and video market is continuously expanded, so that various service modes including live broadcast, video cloud PaaS and video conferences are developed, and the real-time audio and video services can attract users with various requirements.
For real-time traffic, real-time is both an advantage and a necessary requirement, i.e. it must maintain a consistent low delay characteristic. In order to meet the requirements, various technologies such as a congestion control technology, an active queue management system and the like are proposed in both academic circles and industrial circles, and the obvious effect is achieved, and the median of RTT measured by the current large live broadcast platform is less than 100 milliseconds. Now that tail delay gradually becomes a key factor affecting the overall quality of service, users may face delays greater than 400 milliseconds in extreme cases, severely affecting the usage experience. The tail delay is usually caused by network congestion, for example, a large number of users access and interfere with each other at the same time to cause a sudden drop of available bandwidth, so that a large number of data packets are queued, which represents that the existing server is relatively weak against a weak network. The solution of this problem is crucial to improving customer satisfaction.
At present, it is more and more common knowledge that the network congestion phenomenon often occurs in the path from the backbone network to the ue, that is, the last hop of the mobile end is the bottleneck of the whole end-to-end transmission. In fig. 1, the last hop represents transmission from the wireless access device to the receiving client, and the transmission delay and queuing delay generated at this hop are main factors contributing to the rise of the end-to-end delay and network congestion.
Based on the above analysis, in order to better enable the real-time communication service to resist the weak network, it is necessary to provide a feedback scheme of congestion state in the network, and by feeding back the congestion signal of the last hop to the sending end in advance, the sending end can adjust the bandwidth in time, adapt to the network change, and meet the user's requirements.
Disclosure of Invention
The invention provides a method, a device, a medium, wireless access equipment and a system for feeding back an in-network state, which aim to solve the problems of weak network and network disconnection from a communication server to a client.
In a first aspect, an embodiment of the present invention provides an in-network state feedback method, applied to a wireless access device, including:
performing delay estimation on each downlink data packet arriving at the wireless access device;
calculating a delay increment between adjacent downlink data packets based on the estimated delay and maintaining a delay profile of the ACK packets fed back by the uplink based on the delay increment;
when the ACK packet arrives at the wireless access device, an adaptive out-of-band feedback signal control mechanism is utilized to delay the transmission of the ACK packet.
In some implementations, the estimating the delay of each downlink packet arriving at the wireless access device includes:
measuring the length of a current queue and the dequeuing rate;
calculating the queuing time of the downlink data packet in the current queue based on the current queue length and the dequeuing rate;
acquiring the waiting time of a downlink data packet at the head of the queue at the moment;
measuring the time interval of the downlink data packet leaving the queue, and further estimating the total delay of the downlink data packet, including the sum of the queuing time, the waiting time and the time interval.
In some implementations, the maintaining a delay profile of ACK packets for uplink feedback based on the delay delta includes:
if the delay increment is positive, putting the delay increment into a sampling pool to update the delay distribution;
and if the delay increment is a negative number, the absolute value of the delay increment is used as the first token to be placed in the token pool.
In some implementations, delaying the sending of the ACK packet by using an adaptive out-of-band feedback signal control mechanism when the ACK packet arrives at the wireless access device includes:
sampling a delay increment from the sampling pool when an ACK packet arrives at a wireless access device;
judging whether a token exists in a token pool or not;
preferentially consuming the tokens in the token pool under the condition that the tokens exist in the token pool, subtracting the consumed tokens on the basis of the sampled delay increment, delaying an ACK packet on the basis of the delay increment remained after the tokens are consumed, and deleting the consumed tokens from the token pool;
in the event there are no tokens in the token pool, the ACK packet is delayed based on the sampled delay increment.
In some implementations, delaying the sending of the ACK packet using an adaptive out-of-band feedback signal control mechanism when the ACK packet arrives at the wireless access device further includes:
and if the delayed ACK packet violates the original transmission sequence of the transmission protocol, calculating and storing a second token according to a calculation formula of the second token and putting the second token into the token pool.
In some implementations, delaying the sending of the ACK packet using an adaptive out-of-band feedback signal control mechanism when the ACK packet arrives at the wireless access device further includes:
the outdated tokens in the token pool are periodically updated and deleted.
In some implementations, the second token is calculated as follows:
token＝arr j+1 +sample j+1 -arr j+2 -sample j+2
wherein token is the second token, arr j+2 And arr j+1 The arrival times, sample, of ACK packet j +2 and ACK packet j +1, respectively j+2 And sample j+1 The delay increments sampled from the sampling pool for ACK packet j +2 and ACK packet j +1, respectively.
In a second aspect, an embodiment of the present invention provides an intra-network state feedback apparatus, including:
a delay estimation module for performing delay estimation on each downlink data packet arriving at the wireless access device;
a delay profile maintenance module for calculating a delay increment between adjacent downlink data packets based on the estimated delay and maintaining a delay profile of an ACK packet fed back by an uplink based on the delay increment;
and the feedback delay module is used for delaying the sending of the ACK packet by using an adaptive out-of-band feedback signal control mechanism when the ACK packet reaches the wireless access equipment.
In a third aspect, an embodiment of the present invention provides a computer-readable storage medium, where a computer program is stored on the storage medium, and when the computer program is executed by one or more processors, the in-network state feedback method according to the first aspect is implemented.
In a fourth aspect, an embodiment of the present invention provides a wireless access device, including a memory and one or more processors, where the memory stores a computer program, and the computer program is executed by the one or more processors to implement the in-network state feedback method according to the first aspect.
In a fifth aspect, an embodiment of the present invention provides an audio and video real-time transmission system, which includes the wireless access device in the fourth aspect.
Compared with the prior art, one or more embodiments of the invention can bring at least the following beneficial effects:
the invention predicts the delay of the last hop according to the information of queue and the like at the wireless access point, and feeds the current network state back to the sending end in advance, so that the sending end can sense that the network is congested, thereby reducing the sending rate of the sending end to adapt to the change of the network in time, and a user is free from enduring larger frame delay caused by unmatched bandwidth.
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In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
FIG. 1 is a diagram of an RTC system architecture in the related art;
fig. 2 is a flowchart of an intra-network state feedback method according to an embodiment of the present invention;
fig. 3 is a flowchart of another intra-network state feedback method according to an embodiment of the present invention;
fig. 4 is a schematic diagram of an intra-network state feedback device according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.
The embodiment of the invention provides an in-network state feedback method, an in-network state feedback device, an in-network state feedback medium, an in-network state feedback wireless access device and an in-network state feedback system, which are implemented on a last-hop wireless access device of an audio and video real-time transmission system and used for solving the problems of weak network and broken network of the last-hop network.
The scheme of the invention relates to three aspects of mutual synergy:
firstly, a feedback signal in a transmission protocol based on out-of-band feedback is used for transmitting an in-network state, and a transmission rule is compatible: based on the transmission protocol with out-of-band feedback, such as a TCP protocol, a client confirms that each received data packet sends back an ACK packet, and after receiving the ACK packet, a sender automatically calculates network conditions such as RTT (Round-Trip Time), receiving rate, and the like, and gives a reasonable sending rate decision, but the client does not have the capability of directly understanding a network feedback signal (such as available bandwidth), and a feedback packet does not exist in connection. In view of this problem, the feedback mechanism design needs to be compatible with these existing transmission protocols, so that the modifications on the early feedback in the feedback mechanism do not affect the implementation of the original transmission mechanism and the feedback signal can be successfully identified by the sender. Therefore, the method converts the predicted network conditions into signals which can be understood by a sender, creatively delays a reverse ACK packet to bring back to an in-network state when a downlink data packet arrives, and simultaneously maintains the distribution of the in-network state to solve the problem that the data packet and the ACK packet are asynchronous, so that the continuously updated state distribution stored in the router provides guidance for a transmission protocol and a congestion control algorithm through a feedback signal according to the probability of being closest to a real-time real network state.
Secondly, the feedback signal is estimated by combining the current queue in the network and the transmission state of the wireless channel: since the devices in the network are the providers of feedback information, some signals originally sensed at the end, such as round trip delay, are predicted according to the information such as queue length, sending rate, etc. that can be grasped at the access point, and the receiving rate is used as feedback signals. Because the frequency and the amplitude of the change of the wireless network state are large, the wireless network state has an independent packet sending mode, and the state change under a transient state mode and a steady state mode exists, the estimation and the prediction of the wireless network state are difficult, therefore, the method decomposes the queuing delay into a long-term state quantity and a short-term state quantity according to the transmission characteristics of a wireless channel, and predicts the total queuing delay of the data packet together.
Third, the adaptive out-of-band feedback signal control mechanism: for the original transmission sequence and packet loss state of the transmission protocol, for example, the transmission protocol based on TCP has a fixed sequence and different processing modes for the received ACK (acknowledgement character) data packet, the advance feedback mechanism needs to correctly transmit the network feedback signal to the sender without degrading the original transmission state. Therefore, the method needs to adaptively adjust the action of the feedback signal transmission back end when facing different transmission states, maintains the transmission state without the phenomenon of contradiction with the protocol, and meanwhile, because the effect on the original feedback result is generated by modifying the early feedback mechanism according to the original transmission rule, the state distribution in the early feedback mechanism needs to be adaptively restored and adjusted to adapt to the effect.
Example one
The embodiment provides an in-network state feedback method, which is applied to a last hop wireless access device (AP) of an audio and video real-time transmission system, and in practical application, the wireless access device may be a wireless router, a WiFi access point, a cellular network base station, or the like, as shown in fig. 2, and at least includes step S101 to step S103:
step S101, delay estimation is performed for each downlink packet arriving at the wireless access device.
Aiming at the problem that the available bandwidth of an access network is reduced due to network jitter and increase of competitive users, the method designs a queue-based hybrid delay estimation method, and has the technical idea that due to instability of a wireless link, the method decomposes queuing delay into different parts, introduces long-term and short-term estimation quantities, measures average dequeuing rate to calculate long-term queuing delay, the staying time of a data packet in front of the queue (the head of the queue) responds to short-term fluctuation, and the total delay of downlink data packets also comprises transmission delay besides the queuing delay. Meanwhile, by combining the three types of delay, more accurate estimation of the transmission delay of the last hop wireless route can be obtained.
Therefore, in some implementations, as shown in fig. 3, the above step S101 of performing delay estimation on each downlink data packet arriving at the wireless access device may include the following sub-steps:
step S101a, measuring the current queue length and dequeue rate.
The measurement of the queue length qLen is performed when each packet arrives at the AP, and the transmission rate txRate (also the dequeue rate) of the downlink from the AP to the client is set as a moving average of the transmission rates measured in the past period, where the transmission rate is for the streams corresponding to the series of packets, because there may be a case where a plurality of streams share the transmission rate in the AP, and therefore, in order to meet the actual situation, the transmission rate of a single stream is used here.
Step S101b, calculating a queuing time qDelay = qLen/txRate of the downlink data packet in the current queue based on the current queue length and the dequeuing rate.
To avoid bursty wireless network packet-sending rules, the queue length can be summed to the existing length minus the queue length that would be immediately dequeued due to frame aggregation, meaning that this part would not follow the normal queuing rules.
In step S101c, the waiting time of the downlink packet at the head of the queue at this time is obtained.
In some cases, the operation timing of obtaining the waiting time of the downlink data packet at the head of the queue at this time is implemented, that is, it is performed according to a certain frequency, for example, every 5ms, to check the waiting time of the downlink data packet at the head of the queue, specifically, to check whether the downlink data packet at the head of the queue has changed, if the head of the queue becomes a new downlink data packet, from this time to the time when the new downlink data packet is sent from the radio access device AP or from this time to the aggregation frame where the new downlink data packet is sent from the radio access device AP, this elapsed time is the waiting time wait at the head of the queue in the new downlink data packet, and the WaitTime taken when the downlink data packet arrives is the waiting time of the packet at the head of the queue at this time.
Step S101d, measuring the time interval of the downlink data packet leaving the queue, and further estimating the total delay of the downlink data packet, including the sum of the queuing time, the waiting time and the time interval.
The transmission delay of a data packet is the time interval during which the data packet leaves the queue, because the transmission of the wireless channel is data frame by data frame, and the transmission of a data frame is started after the previous data frame arrives. However, a data frame may contain a plurality of data packets, and this time interval cannot be measured by the granularity of the data packets, otherwise, a plurality of queue leaving time intervals which are continuously 0 may occur, so the method aggregates the queue leaving time intervals according to a certain time granularity, and estimates the transmission delay by using the aggregated data statistics queue leaving time intervals. By such a method, the downlink data packet transmission delay can be measured, and the total delay of the downlink data packet can be estimated, including the sum of the queuing time, the waiting time and the transmission delay. The method estimates the total delay through the sum of the queuing time, the waiting time and the time interval, realizes the estimation of the mixed delay, and further can calculate the delay increment between the adjacent downlink data packets based on the estimated total delay, namely the difference of the total delay between the adjacent downlink data packets.
Step S102, delay increment between adjacent downlink data packets is calculated based on the estimated delay, and the delay distribution of the ACK packets fed back by the uplink is maintained based on the delay increment.
In practice, TCP-based RTC systems have multiple congestion control algorithms, although they all use ACK packets as the basis for out-of-band feedback, but various algorithms use them in different ways. For example, the BBR congestion control algorithm counts the minimum RTT of ACK packets for rate adaptation, while the Copa congestion control algorithm is sensitive to the delay of each ACK packet. To meet the requirements of different congestion control algorithms, the method faithfully provides the estimated delay at the finest per packet granularity by delaying ACK packets. The congestion control algorithm may then aggregate the fine-grained information and react in its own way. In the congestion control algorithm, when the interval of dequeuing two adjacent data packets from the wireless access device AP is increased due to the decrease of available bandwidth or the addition of competing data streams of a downlink data packet, information indicating network congestion needs to wait until two ACK data packets corresponding to the reverse direction return to the server with an increased delay, the server can sense the delay and the network condition and reduce the data transmission rate, and the advanced feedback mechanism shortens the control period. The congestion information does not need to go through queuing and the round trip time of the last hop, and is returned to the peer directly following the most recent ACK.
By delaying the sending of the ACK packet and utilizing the original confirmation mechanism of the transmission protocol, the method feeds back the state in the network in advance without manufacturing redundant bandwidth consumption. In order to meet the requirements of different congestion control algorithms, estimate of transmission delay is provided at the finest granularity of each data packet, and the distribution uniformity of the estimated transmission delay and the actual delay in the transient state and the steady state is recorded and continuously updated, so that the congestion control algorithms are quickly guided to the nearest real network condition.
The network state is generally divided into a steady state and a transient state, and in order to ensure that the delay distribution maintained by the method and the delay operation of the ACK data packet do not influence the normal RTT estimation, the method respectively performs the following operations on the steady state and the transient state:
for steady state: in order to avoid that the congestion control algorithm exaggerates the true RTT and makes erroneous decisions due to the long queuing delay in the wireless access device AP causing the reverse ACK packet to be sent continuously with a delay, the method does not directly add the absolute estimated transmission delay of the downlink data packet to the delay of the ACK packet. Instead, the delay delta, i.e. the delay difference between consecutive downlink packets, is recorded. As the estimated transmission delay increases, the wireless access device AP records a series of delay increments and gradually increases the delay of the ACK packet. When the queue is stably established, the delay increment is maintained near zero, and the ACK packet fed back by the uplink cannot be influenced by extra delay;
for transients: the direct use of the delay delta mechanism may not provide short term delay fluctuations. The reason is that the long-term delay is averaged and varies slowly, and a non-zero delay delta generated by multiple downlink data packets can be carried in one ACK packet. In contrast, the short-term delay varies from packet to packet. Not every delay increment may be carried in a single ACK packet. The disparity in the downlink data packets and the ACK packets fed back by the uplink may cause multiple delay increments to accumulate in one ACK packet, which is not in line with the fact. Therefore, for each calculated delay increment of each data packet, the method does not directly superimpose the delay increment on the reverse ACK packet, but each delay increment is put into a sampling pool as a possible sample to be sampled by each reverse ACK packet (it is clear here that if the delay increment is a positive number, the ACK packet should be delayed, but if the delay increment is a negative number, congestion is relieved or only a data packet burst situation is met, and the delay of the ACK packet should be avoided), so that the distribution equivalence between the delay increment of the forward link and the delay of the reverse link ACK packet can be maintained, the distribution consistency between the actual delay and the predicted delay is optimized, and the two are accurately matched. The method further maintains a distribution of delay increments over a recent period of time for updating forward (link) packets.
Based on this, the above step S102 calculates a delay increment between adjacent downlink data packets based on the estimated delay, and maintains a delay profile of the ACK packet fed back by the uplink based on the delay increment, and may further include the following sub-steps:
step S102a, calculating delay increment between adjacent downlink data packets based on the estimated delay;
step S102b, maintaining the delay distribution of the ACK packet fed back by the uplink based on the delay increment;
if the delay increment is positive, putting the delay increment into a sampling pool to update the delay distribution;
and if the delay increment is a negative number, the absolute value of the delay increment of the negative number is used as the first token to be placed in the token pool.
When the ACK packet arrives at the wireless access device AP, the wireless access device AP samples a delay increment from the sampling pool and delays transmission of the ACK packet using the delay increment obtained by the sampling, which may preferably be randomly sampled from the sampling pool. Under this mechanism, even if burst packet arrival and departure occur, the wireless access device AP can simulate the delay profile of the fed-back ACK packet. And the maintained delay distribution needs to be updated continuously and periodically, and outdated delay increment samples in the sampling pool are deleted to truly simulate the in-network state in the recent period of time and keep the consistency of steady-state and transient real delay and the delay distribution in the sampling pool.
Step S103, when the ACK packet reaches the wireless access device, the transmission of the ACK packet is delayed by using an adaptive out-of-band feedback signal control mechanism.
Applying a delay delta to the uplink feedback ACK packet introduces an additional challenge of ACK packet order preservation. For example, if ACK packet j +1 and ACK packet j +2 arrive at the same time and the delay of ACK packet j +2 sampling is smaller than ACK packet j +1, the wireless access device may send ACK packet j +2 before ACK packet j +1, which may cause confusion between the fed-back ACK packet and the sender. However, the sending time of the ACK packet fed back subsequently is directly limited to the ACK packet fed back previously, for example, if the ACK packet j +2 is equal to the ACK packet j +1 and the ACK packet j +1 is sent completely, it means that the ACK packet j +2 is artificially delayed for a while, which may result in overestimation and incorrect decision of the end-to-RTT. The method therefore generates a token to preserve the order of the ACK packets while also avoiding overestimation of the RTT. When a subsequent ACK packet needs to wait for the transmission of the previous ACK packet, a second token is stored, and the definition of the second token is as follows:
token＝arr j+1 +sample j+1 -arr j+2 -sample j+2
wherein, arr j+2 And arr j+1 The arrival times, sample, of ACK packet j +2 and ACK packet j +1, respectively j+2 And sample j+1 The second token is put into the token pool and is stored together with the first token generated when the delay increment is negative, the first token and the second token can prevent the delay of the ACK packet, so when a new delay increment is sampled next time, the token in the token pool is tried to be consumed (the delay increment minus the token value), and then the processed delay increment value sample is used, of course, if the delay increment is already reduced to 0 under the condition that all the tokens in the token pool are not consumed, the current ACK packet cannot be delayed, and the consumed token is deleted from the token pool. In this case, the average value of the actual transmission delay will remain the same as the estimated transmission delay, and the consistency of the actual transmission delay profile and the estimated transmission delay profile is also maintained.
To guarantee the transmission order and the rules, the method implements an adaptive out-of-band feedback signal control mechanism. Therefore, the step S103 mentioned above uses the adaptive out-of-band feedback signal control mechanism to delay the transmission of the ACK packet when the ACK packet arrives at the wireless access device, and may further include the following sub-steps:
step S103a, when the ACK packet reaches the wireless access equipment, sampling a delay increment from the sampling pool;
step S103b, judging whether a token exists in the token pool; it should be understood that the token pool may have the first token and/or the second token stored therein.
Step S103c, under the condition that the token pool has the token, preferentially consuming the token in the token pool, subtracting the consumed token on the basis of the sampled delay increment, delaying an ACK packet on the basis of the residual delay increment, and deleting the consumed token from the token pool;
and step S103d, when no token exists in the token pool, delaying the ACK packet based on the delay increment of the sampling.
In some implementations, the step S103, when the ACK packet arrives at the wireless access device, utilizes an adaptive out-of-band feedback signal control mechanism to delay the sending of the ACK packet, and may further include:
and step S103e, if the delayed ACK packet violates the original transmission sequence of the transmission protocol, calculating and storing a second token according to the calculation formula of the second token and putting the second token into the token pool.
The second token is calculated as follows:
token＝arr j+1 +sample j+1 -arr j+2 -sample j+2
wherein token is the second token, arr j+2 And arr j+1 The arrival times, sample, of ACK packet j +2 and ACK packet j +1, respectively j+2 And sample j+1 The delay increments sampled from the sampling pool for ACK packet j +2 and ACK packet j +1, respectively.
In some implementations, the first-in first-out principle is used when the tokens in the token pool are consumed preferentially, and the first-in token is consumed preferentially.
In some implementations, delaying the sending of the ACK packet using an adaptive out-of-band feedback signal control mechanism when the ACK packet arrives at the wireless access device further includes:
and step S103f, periodically updating and deleting the outdated token in the token pool.
It should be noted that the present embodiment does not set any limitation on the type of the feedback control signal, and the method is not limited by the type of the feedback control signal of the transmission protocol. For example, the case of a control signal with transmission delay as a center (for example, a control method for adjusting the rate by RTT, packet interval, delay gradient, etc.) may be used, but the method may be easily extended to the case of other control signals (for example, packet loss, etc.).
In the method of the embodiment, a feedback signal based on an out-of-band feedback transmission mechanism is established and maintained, feedback information is creatively and implicitly transmitted aiming at the transmission protocol mechanism with the out-of-band feedback, and the challenge of compatibility of the existing transmission protocol is solved; the steady-state and instantaneous queue states of the router queue are utilized to accurately predict signals such as delay, speed and the like of a data packet at the last hop, and hybrid delay estimation based on the queue is realized; an adaptive out-of-band feedback frequency control mechanism is established, network state feedback is added to a return data packet, and meanwhile the original transmission sequence and state of a transmission protocol can be adaptively met without influencing original transmission. The scheme is suitable for the transmission protocol with the out-of-band feedback based on various RTC systems such as TCP or QUIC.
Meanwhile, the method is easy to deploy in a large scale and is compatible with the existing transmission protocol. On one hand, compared with the situation that a DCQCN needs to generate a new message, an XCP and an RCP need to write estimation information into a self-defined transmission protocol, and ABC needs to modify some fields of the existing message, the method utilizes a feedback mechanism of the existing transmission protocol to enable the original ACK message in transmission to automatically carry feedback information to a transmitting end, the transmitting end does not need to modify any information or know any change of equipment in a network, and the feedback signal is identified and processed while the rate is adaptively adjusted according to the original rate control protocol. Therefore, the equipment of the sending end and the client end does not need to be forcibly modified (the selection of a client is difficult to control), the universality is improved, and the cost of daily development and maintenance is also saved, so that the practical deployment of the scheme is stronger.
On the other hand, compared with schemes such as FastACK which do not need to change the transmitting end, the method aims at improving the delay performance. The main goal of FaskACK is to improve the throughput of the wireless access device, not to keep the delay low. Furthermore, in FastACK, the feedback signal only advances the transmission delay of the reverse ACK in the wireless channel, and compared to the method, its advanced feedback mechanism is not enough to meet the requirement of low tail delay. Whether the queuing delay, which is important in the present method, is contained in the FastACK or in the control loop may lead to a situation where network congestion information cannot be brought back in time.
Finally, it should be noted that, the method is directed to a transmission protocol based on out-of-band feedback, such as TCP, which does not directly record a feedback packet of a network state but senses a congestion state by using an ACK packet in an acknowledgement mechanism, so that, unlike a scheme that needs to modify the content of the feedback packet to feed back in advance, the method needs to be compatible with such a transmission protocol, cannot create a new feedback packet to increase network load, and cannot be identified by a sending end. Considering that the ACK packet itself cannot extend its message content, the method needs to implicitly transfer the in-network state by using the time when the ACK packet arrives at the sending end.
Example two
As shown in fig. 4, the present embodiment provides an intra-network state feedback apparatus, including:
a delay estimation module 201, configured to perform delay estimation on each downlink data packet arriving at the wireless access device;
a delay profile maintenance module 202, configured to calculate a delay increment between adjacent downlink data packets based on the estimated delay, and maintain a delay profile of ACK packets fed back by the uplink based on the delay increment;
a feedback delay module 203, configured to delay sending of the ACK packet by using an adaptive out-of-band feedback signal control mechanism when the ACK packet arrives at the wireless access device.
In some implementations, the delay estimation for each downlink packet arriving at the wireless access device may include the sub-steps of:
measuring the length of a current queue and the dequeuing rate;
calculating the queuing time qDelay of the downlink data packet in the current queue based on the current queue length and the dequeuing rate;
acquiring the waiting time of the downlink data packet at the head of the queue at the moment;
measuring the time interval of the downlink data packet leaving the queue, and further estimating the total delay of the downlink data packet, including the sum of the queuing time, the waiting time and the time interval.
In some implementations, calculating a delay delta between adjacent downlink data packets based on the estimated delay and maintaining a delay profile of ACK packets for uplink feedback based on the delay delta may further include:
calculating a delay delta between adjacent downlink packets based on the estimated delay;
maintaining a delay profile of ACK packets for uplink feedback based on the delay delta;
if the delay increment is positive, putting the delay increment into a sampling pool to update the delay distribution;
and if the delay increment is a negative number, the absolute value of the delay increment of the negative number is used as the first token to be placed in the token pool.
In some implementations, delaying the sending of the ACK packet using an adaptive out-of-band feedback signal control mechanism when the ACK packet arrives at the wireless access device may further include:
sampling a delay increment from the sampling pool when an ACK packet arrives at the wireless access device;
judging whether a token exists in a token pool or not; it should be understood that the token pool may have the first token and/or the second token stored therein.
Preferentially consuming tokens in the token pool if the tokens exist in the token pool, subtracting the consumed tokens on the basis of the sampled delay increment, delaying an ACK packet on the basis of the remaining delay increment, and deleting the consumed tokens from the token pool; and
in the absence of tokens in the token pool, the ACK packet is delayed based on the delay increment of the sample.
In some implementations, when the ACK packet arrives at the wireless access device, using an adaptive out-of-band feedback signal control mechanism to delay the sending of the ACK packet may further include:
and if the delayed ACK packet violates the original transmission sequence of the transmission protocol, calculating and storing a second token according to a calculation formula of the second token and putting the second token into the token pool.
The second token is calculated as follows:
token＝arr j+1 +sample j+1 -arr j+2 -sample j+2
wherein token is the second token, arr j+2 And arr j+1 The arrival times, sample, of ACK packet j +2 and ACK packet j +1, respectively j+2 And sample j+1 The delay increments sampled from the sampling pool for ACK packet j +2 and ACK packet j +1, respectively.
In some implementations, the first-in first-out principle is used when the tokens in the token pool are consumed preferentially, and the first-in stored tokens are consumed preferentially.
In some implementations, delaying the sending of the ACK packet by using an adaptive out-of-band feedback signal control mechanism when the ACK packet arrives at the wireless access device, further includes:
outdated tokens in the token pool are periodically updated and deleted.
It should be understood that the apparatus of the present embodiment provides all of the benefits of the method embodiments.
Those skilled in the art should understand that the above modules or steps can be implemented by a general purpose computing device, they can be centralized on a single computing device or distributed on a network composed of a plurality of computing devices, and alternatively, they can be implemented by program codes executable by the computing devices, so that they can be stored in a storage device and executed by the computing devices, or they can be respectively manufactured into various integrated circuit modules, or a plurality of modules or steps in them can be manufactured into a single integrated circuit module. The present invention is not limited to any specific combination of hardware and software.
EXAMPLE III
The present embodiments provide a computer-readable storage medium having a computer program stored thereon, where the computer program, when executed by one or more processors, implements the method as provided in the first embodiment.
In this embodiment, the storage medium may be implemented by any type of volatile or nonvolatile storage device or combination thereof, such as a Static Random Access Memory (SRAM), an Electrically Erasable Programmable Read-Only Memory (EEPROM), an Erasable Programmable Read-Only Memory (EPROM), a Programmable Read-Only Memory (PROM), a Read-Only Memory (ROM), a magnetic Memory, a flash Memory, a magnetic disk, or an optical disk. The content of the method is described in the first embodiment, and is not described herein again.
Example four
The present embodiment provides a wireless access device, which includes a memory and one or more processors, the memory stores a computer program, and when executed by the one or more processors, the computer program implements the method of the foregoing embodiment.
In this embodiment, the Processor may be an Application Specific Integrated Circuit (ASIC), a Digital Signal Processor (DSP), a Digital Signal Processing Device (DSPD), a Programmable Logic Device (PLD), a Field Programmable Gate Array (FPGA), a controller, a microcontroller, a microprocessor, or other electronic components, and is configured to perform the method in the above embodiments. The method implemented when the computer program running on the processor is executed may refer to the specific embodiments of the methods provided in the foregoing embodiments of the present invention, and details are not described here.
In some implementations, the wireless access device can be a wireless router, a WiFi access point, a cellular network base station, or the like.
EXAMPLE five
The embodiment provides an audio and video real-time transmission system, which includes the wireless access device described in the foregoing embodiment.
In the several embodiments provided in the embodiments of the present invention, it should be understood that the disclosed system and method may be implemented in other manners. The system and method embodiments described above are merely illustrative.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrases "comprising one of 8230; \8230;" 8230; "does not exclude the presence of additional like elements in a process, method, article, or apparatus that comprises the element.
Although the embodiments of the present invention have been described above, the above description is only for the purpose of understanding the present invention, and is not intended to limit the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (11)
1. An in-network state feedback method, applied to a wireless access device, includes:
performing delay estimation on each downlink data packet arriving at the wireless access device;
calculating a delay increment between adjacent downlink data packets based on the estimated delay and maintaining a delay profile of the ACK packets fed back by the uplink based on the delay increment;
when the ACK packet arrives at the wireless access device, an adaptive out-of-band feedback signal control mechanism is utilized to delay the transmission of the ACK packet.
2. The in-network state feedback method of claim 1, wherein said performing delay estimation for each downlink packet arriving at the wireless access device comprises:
measuring the length of a current queue and the dequeuing rate;
calculating the queuing time of the downlink data packet in the current queue based on the current queue length and the dequeuing rate;
acquiring the waiting time of the downlink data packet at the head of the queue at the moment;
measuring the time interval of the downlink data packet leaving the queue, and further estimating the total delay of the downlink data packet, including the sum of the queuing time, the waiting time and the time interval.
3. The in-network state feedback method according to claim 1, wherein said maintaining a delay profile of ACK packets fed back in uplink based on said delay delta comprises:
if the delay increment is positive, putting the delay increment into a sampling pool to update the delay distribution;
and if the delay increment is a negative number, the absolute value of the delay increment is used as the first token to be placed in the token pool.
4. The in-network state feedback method according to claim 3, wherein said delaying the sending of the ACK packet by using an adaptive out-of-band feedback signal control mechanism when the ACK packet arrives at the wireless access device comprises:
sampling a delay increment from the sampling pool when an ACK packet arrives at the wireless access device;
judging whether a token exists in the token pool or not;
preferentially consuming the tokens in the token pool under the condition that the tokens exist in the token pool, subtracting the consumed tokens on the basis of the sampled delay increment, delaying an ACK (acknowledgement) packet on the basis of the delay increment left after the tokens are consumed, and deleting the consumed tokens from the token pool;
in the absence of tokens in the token pool, the ACK packet is delayed based on the delay increment of the sample.
5. The in-network state feedback method of claim 4, wherein the delaying of the sending of the ACK packet by an adaptive out-of-band feedback signal control mechanism when the ACK packet arrives at the wireless access device further comprises:
and if the delayed ACK packet violates the original transmission sequence of the transmission protocol, calculating according to a calculation formula of the second token and storing the second token to be placed in the token pool.
6. The in-network state feedback method according to claim 5, wherein said delaying the sending of the ACK packet by using an adaptive out-of-band feedback signal control mechanism when the ACK packet arrives at the wireless access device, further comprises:
the outdated tokens in the token pool are periodically updated and deleted.
7. The in-network state feedback method according to claim 5, wherein said second token is calculated as follows:
token＝arr j+1 +sample j+1 -arr j+2 -sample j+2
wherein token is the second token, arr j+2 And arr j+1 The arrival times, sample, of ACK packet j +2 and ACK packet j +1, respectively j+2 And sample j+1 The delay increments sampled from the sampling pool for ACK packet j +2 and ACK packet j +1, respectively.
8. An in-network state feedback device, comprising:
a delay estimation module for performing delay estimation on each downlink data packet arriving at the wireless access device;
a delay profile maintenance module for calculating a delay increment between adjacent downlink data packets based on the estimated delay and maintaining a delay profile of an ACK packet fed back by an uplink based on the delay increment;
and the feedback delay module is used for delaying the sending of the ACK packet by utilizing an adaptive out-of-band feedback signal control mechanism when the ACK packet reaches the wireless access equipment.
9. A computer-readable storage medium, having stored thereon a computer program which, when executed by one or more processors, implements the in-network state feedback method of any of claims 1-7.
10. A wireless access device comprising memory and one or more processors, the memory having stored thereon a computer program that, when executed by the one or more processors, implements the in-network state feedback method of any of claims 1-7.
11. An audiovisual real-time transmission system, characterized in that it comprises a wireless access device according to claim 10.
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