CN1964275A - A realization method to dynamically change maximum length of bandwidth request - Google Patents

Abstract

The present invention proposes a method for dynamically changing the maximum length of a bandwidth request, including the following steps: 1. Within a set time period, the base station side counts the remaining bandwidth of the current system, according to the number of mini-slots, the number of bytes, and the weight 1. The sequence of the corresponding values of the terminal calculates the maximum transmission data length of each terminal in a bandwidth allocation map; 2. The base station notifies the terminal of the maximum length of the transmitted data; 3. The terminal notifies the framing module of the received data length; 4. The framing module performs framing according to the data length; 5. The terminal makes a bandwidth request according to the length of the data frame. The method of the invention enables a single user to dynamically adjust the maximum length of the data frame requested by the bandwidth according to the current bandwidth of the system, dynamically changes the current flow according to the occupation of the system bandwidth, and effectively utilizes the system bandwidth.

Description

A Realization Method of Dynamically Changing the Maximum Length of Bandwidth Request

technical field

The invention relates to a point-to-point access system and a point-to-multipoint access system in the field of communication, dynamically adjusting the maximum length of a data frame according to the real-time occupancy of the system bandwidth, so that the requested data length changes accordingly, so as to dynamically change the uplink data service flow implementation method.

Background technique

The broadband access system adopts the point-to-multipoint (wireless/wired) transmission mode to realize fixed integrated service (data/circuit) access between the user network and the backbone network, and its service objects are mainly group users, used in enterprises and residential quarters Waiting for the comprehensive access of users.

In a point-to-multipoint access system, the system is generally divided into two parts, one is the terminal, and the other is the base station. The base station side controls data transmission timing and data transmission length. Before sending data, the terminal must request bandwidth from the base station. The base station allocates bandwidth to the terminal by comprehensively considering the quality of services (QoS) of the service. The bandwidth allocation information forms a certain periodic bandwidth allocation map (MAP). The bandwidth allocation information in the send data. The TDMA (Time Division Multiple Access) access method used in the uplink of the entire access system.

Some of the current broadband point-to-multipoint access systems support a single service and some support multiple services. However, no matter whether it supports single service or multiple services, when making a bandwidth request, the terminal does not know the bandwidth occupancy of the current system, so the following two phenomena may occur when making a bandwidth request:

1. The length of the requested bandwidth is greater than the remaining bandwidth available for allocation in the current system, resulting in the inability to send the entire data frame within a single MAP cycle, and the data frame can only be completely sent out in multiple MAPs, which leads to service air delays increase;

2. The requested bandwidth length is far less than the remaining bandwidth of the current system, resulting in waste of air bandwidth.

How to enable users to effectively use the air bandwidth without increasing the air delay, and at the same time increase the maximum uplink traffic in the case of single-terminal configuration of the system is an unsolved issue at present.

Contents of the invention

The purpose of the present invention is to provide a method suitable for point-to-point and point-to-multipoint broadband access systems, dynamically changing the maximum request length according to the system bandwidth occupancy, so that a single user (terminal) can dynamically adjust according to the current bandwidth of the system The maximum length of the data frame requested by the bandwidth, dynamically changes the current traffic according to the system bandwidth occupancy, and effectively utilizes the system bandwidth.

An implementation method for dynamically changing the maximum length of a bandwidth request of the present invention comprises the following steps:

1) Within the set time period, the base station side counts the remaining bandwidth of the current system, and calculates the maximum send data length;

2) The base station notifies the terminal of the maximum length of the data to be sent;

3) The terminal notifies the framing module of the received data length;

4) The framing module performs framing according to the data length;

5) The terminal makes a bandwidth request according to the length of the data frame.

Above-mentioned method, the remaining bandwidth statistics of current system in described step 1) comprises the following steps:

1.1) Determine the period of a bandwidth allocation map MAP and the number of mini-slots of the total bandwidth available for distribution, count the number of successful terminal registrations at present, subtract the overhead bandwidth of the normal operation of the terminal from the total bandwidth, and obtain the first bandwidth;

1.2) Take one second as a period to count the current uplink traffic of each terminal. If the uplink traffic of the terminal is greater than the set value (such as the minimum guaranteed uplink bandwidth of the terminal), the terminal needs to adjust the current maximum bandwidth request length, Count the number of terminals that need to adjust the maximum length of the bandwidth request data; if the upstream traffic of the terminal is less than the set value (such as the minimum guaranteed upstream bandwidth of the terminal), subtract the occupied bandwidth of the terminal from the first bandwidth, Obtain the second bandwidth, and use the conversion formula to convert the number of mini-slots into the number of bytes;

1.3) According to the service quality QoS priority of each terminal, determine the weight value of the maximum length of the adjustment request data of different terminals, and calculate the corresponding value of each terminal according to the weight value.

In the above method, in the step 2), the base station organizes the information in the uplink channel descriptor data in the form of type and length value, and sends it to each terminal in the form of broadcast.

In the above method, in the step 4), the framing is performed in the form of concatenated frames.

The method for dynamically changing the maximum request length according to the system bandwidth occupancy of the present invention enables a single user (terminal) to dynamically adjust the maximum length of the data frame of the bandwidth request according to the current system bandwidth and dynamically change the current traffic according to the system bandwidth occupancy , effectively utilizing the system bandwidth.

Description of drawings

Figure 1 is a flowchart for dynamically changing the maximum length of a request;

Figure 2 is a schematic diagram of an organizational form of TLV;

Fig. 3 is a schematic diagram of the structure of the concatenated frame header in the DOCSIS protocol;

FIG. 4 is a schematic structural diagram of a concatenated frame in the DOCSIS protocol.

Detailed ways

The specific implementation of the present invention will be briefly described below by taking the service interface specification DOCSIS (Data-Over-Cable Service Interface Specifications) protocol of the data cable as an example. Before describing the specific implementation, let's briefly introduce the DOCSIS protocol.

The DOCSIS protocol is a cable TV network protocol, which mainly specifies the operation specifications of the MAC (media access control) layer and the physical PHY (physical) layer in the point-to-multipoint cable TV network. The MAC layer specifies air bandwidth management and QoS guarantee for business. In the uplink direction, services are sent in the form of MAC frames, and the length of MAC frames is variable. The base station side regularly allocates the sending opportunity of sending the bandwidth request to the terminal. If the terminal side has data to send, it sends the bandwidth request information within the sending opportunity. The base station receives the bandwidth request information and the current system bandwidth occupancy. The terminal then sends the data according to the bandwidth allocation of the base station. Bandwidth allocation information is expressed in MAP frames. The service identifier SID (services identification) in the MAP frame can correspond to a certain terminal, and the MAP information element IE (Information Elements) indicates the allocation of bandwidth. According to the SID and MAP IE, the specific situation of the bandwidth allocation of each terminal can be determined. The MAP information is sent in the form of broadcast. After receiving the MAP frame, the terminal can send data according to the information in the MAP. For details of the DOCSIS protocol, please refer to "Data-Over-Cable Service Interface Specifications Radio Frequency Interface Specification".

With reference to Fig. 1, the realization steps of the present invention are as follows:

1. Count the remaining bandwidth of the current system within a certain period, and convert it from the number of mini-slots to the number of bytes. Residual bandwidth statistics The main tasks of the current system to obtain the remaining bandwidth are as follows:

1.1 In the DOCSIS system, a MAP period is 6ms, and the total bandwidth available for allocation is 192 mini-slots. First count how many terminals have successfully registered at present, and then subtract the overhead bandwidth for maintaining the normal operation of several terminals (such as the bandwidth occupied by periodic ranging, initial ranging, and bandwidth requests) from the total bandwidth to obtain the first bandwidth.

1.2 Take one second as a period to count the current uplink traffic of each terminal. If the uplink traffic of the terminal is greater than a certain value (such as the minimum guaranteed uplink bandwidth of the terminal), it means that the terminal needs to adjust the current maximum bandwidth request length. In this way, the number of terminals that need to adjust the maximum length of bandwidth request data can be counted. If the upstream traffic of the terminal is less than a certain value (such as the minimum guaranteed upstream bandwidth of the terminal), subtract the bandwidth occupied by the terminal from the first bandwidth to obtain the second bandwidth, assuming that the second bandwidth corresponds to the data that can be sent The total length is 5000 bytes. The conversion formula for bandwidth from minislots to bytes is as follows:

Y＝(floor((S*X-PHY)/(K+2*T))*K

Among them, Y indicates the number of bytes obtained, X indicates the number of mini-slots, S indicates the number of bytes that can be accommodated in each mini-slot, PHY indicates the physical overhead, K indicates the K value of the RS code, and T indicates the number of bytes in the RS code. T value, floor means rounding the value.

1.3 According to the QoS priority of each terminal, determine the weight of the maximum length of adjustment request data of different terminals, and calculate the corresponding value of each terminal according to the weight. For example: Assuming that the weight of SU1 with high priority is 5, the weight of SU2 with low priority is 1, and the weight of SU3 with priority is 3, the value of SU1 can be calculated as 5000*5/(5+3+ 1)=2778 bytes, while the value of SU2 is 5000*1/(5+3+1)=555 bytes, and the value of SU3 is 5000*3/(5+3+1)=1667 bytes. If the weights are the same, they are distributed equally. In addition, if the calculated value is less than the maximum length of the Ethernet frame of 1518 bytes, the length is set to 1518 bytes. If the value is greater than the remaining bandwidth of the current system, 5000 bytes, it is equal to 5000 bytes.

2. On the base station, the information is organized in the uplink channel descriptor UCD (up channel descriptor) data in the form of type length value TLV (type length value). The UCD is sent to each terminal in the form of broadcast, and the terminal resolves to the corresponding After the value, notify the data framing module of the value. Figure 2 is an organizational form of TLV.

3. After the data framing module receives the maximum length of the data, it performs framing according to a certain framing method according to the length. In the DOCSIS protocol, cascading frames are used for framing. FIG. 3 is a schematic diagram of a frame header structure of a concatenated frame, and FIG. 4 is a schematic diagram of a frame structure of a concatenated frame.

4. The bandwidth request module reads the length of data from the framing module to form a request frame for bandwidth request.

In the DOCSIS protocol, the length of the class frame is included in the QoS parameter and will not change dynamically. The present invention expands and modifies this point in the DOCSIS protocol, so that the maximum length of the concatenated frame can be dynamically adjusted according to the current situation of the remaining bandwidth in the air, and overcomes the fact that the bandwidth allocation in the current system cannot meet the requirements due to the excessively large requested bandwidth The delay increase phenomenon caused by the situation also overcomes the bandwidth waste phenomenon when the bandwidth is sufficient but the request is too small. The realization of the function of dynamically adjusting the bandwidth request length makes it possible to effectively use the air bandwidth resource without increasing the air delay. The uplink traffic of the terminal can be calculated as follows:

Terminal uplink traffic = 1/Map period (ms) × 1000 × number of bytes sent in each map × 8, when only one terminal accesses, the number of bytes sent in each map varies with the adjustment of the request length Adjust, so that the uplink flow of the terminal increases accordingly.

Claims (6)

1, a kind of implementation method of dynamic change bandwidth request maximum length is characterized in that it comprises the steps:

1) in the time cycle of setting, base station side is added up the remaining bandwidth of current system, goes out maximum data length that sends of each terminal in an allocated bandwidth mapping graph according to the order computation of mini-slot number, byte number, weights, terminal analog value;

2) the base station maximum length that will send data is notified to terminal;

3) terminal is the data length group of notifications frame module that receives;

4) the framing module is carried out framing according to described data length;

5) terminal is carried out bandwidth request according to the length of forming Frame.

2, the implementation method of dynamic change bandwidth request maximum length according to claim 1 is characterized in that, the remaining bandwidth of current system statistics comprises the steps: in the described step 1)

1.1) determine that the cycle of an allocated bandwidth mapping graph and the mini-slot number of distributable total bandwidth, the quantity of adding up current endpoint registration success, total bandwidth deduct the overhead bandwidth of the normal operation of terminal, obtain first bandwidth;

1.2) being a second in cycle, the uplink traffic of current each terminal of statistics, if the uplink traffic of this terminal is greater than set point, then this terminal need be adjusted current maximum bandwidth request length, counts the number of the terminal that needs adjustment bandwidth request data maximum length; If the uplink traffic of this terminal less than set point, just deducts the shared bandwidth of this terminal with first bandwidth, obtain second bandwidth, utilize reduction formula that the mini-slot number is converted into byte number;

1.3) according to the quality of service priority of each terminal, determine the weights of the adjustment request msg maximum length of different terminals, calculate the corresponding value of each terminal according to weights.

3, the implementation method of dynamic change bandwidth request maximum length according to claim 1, it is characterized in that, described step 2) on the base station with the mode of type lengths values information organization in the upstream channel descriptor data, send to each terminal by the forms of broadcasting.

4, the implementation method of dynamic change bandwidth request maximum length according to claim 1 is characterized in that, adopts the mode of cascade frame to carry out framing in the described step 4).

5, the implementation method of dynamic change bandwidth request maximum length according to claim 2 is characterized in that, described step 1.2) in set point be the minimum up assurance bandwidth of this terminal.

6, the implementation method of dynamic change bandwidth request maximum length according to claim 2 is characterized in that, described step 1.2) in, for the DOCSIS system, the reduction formula that the mini-slot number is converted into byte number is:

Y＝(floor((S*X-PHY)/(K+2*T))*K

Wherein, Y represents the byte number that obtains, and X represents the mini-slot number, and S represents the byte number that each mini-slot can hold, and PHY represents physical overhead, and K represents the K value of RS coding, and T represents the T value of RS in encoding, and floor represents that logarithm value rounds operation.

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