WO2007076643A1

WO2007076643A1 - A method and the control device for improving the fairness in the time division multiplex system

Info

Publication number: WO2007076643A1
Application number: PCT/CN2006/000447
Authority: WO
Inventors: Zihua Guo; Shuang Wang
Original assignee: Lenovo (Beijing) Limited
Priority date: 2005-12-31
Filing date: 2006-03-21
Publication date: 2007-07-12
Also published as: CN1996828A; CN1996828B

Abstract

A method and a control device for improving the fairness in the time division multiplex system, the method includes the steps: time slice is distributed for each of the multi-user in the frame according to the predetermined order; the order of the time slice is changed in turn for each user in the frame which is behind the said frame. Using the above configuration, the fairness of the time slice distributed to the user is improved, while providing service for user, so that avoids the degradation of service quality of some users.

Description

Method and control device for improving fairness in time division multiplexing wireless systems

The present invention relates to the field of wireless packet switching technologies, and in particular, to a method for improving the fairness of a time division multiplexed wireless system and a corresponding control device to avoid degradation of service quality of the client. Background technique

In current TDMA-based wireless packet switching systems, such as UWB systems, systems typically do not assign time slice resources to a user as in a circuit switched system, but users typically need to apply to the center on a regular basis. The control point issues a request to get the resource.

In the current research, people usually focus on the scheduling algorithm of the UWB system to improve the QoS and fairness of users to obtain time slice resources. Therefore, many scheduling algorithms such as SRPT, WFQ, WF ² Q, and the like are studied.

When studying these scheduling algorithms, we found that even after a complicated scheduling algorithm, the average time slice of the user can obtain good fairness, but if the resources obtained by the user are different in the position of the TDMA frame, it will greatly affect Its ultimate QoS and fairness.

An example of this is shown in Figure 1, which shows the MAC frame structure of the Book B system. As shown in Fig. 1, after the beacon, the user 1, the user 2, the user 3, the user 4, and the user 5 are sequentially assigned. The time slice at the end of each MAC frame is reserved for each user to send an application to the control point. The control point determines how many time slices are allocated to each user in the next frame, based on the amount of time slices requested by each user and the corresponding scheduling algorithm.

As can be seen from Figure 1, if the relative positions of individual users have been so fixed, for those applications with time requirements (such as A/V streaming), it actually causes a serious problem. Since User 1 always obtains the transmission opportunity at the frame header, when the request is sent to the end of the frame, the information in the buffer is already in the latest state, and it can request the corresponding resource in the next frame according to the latest buffer size. . But for User 5, it is completely different. Since it gets a transmission opportunity at the end of each frame, it must immediately send a request to the central control point based on its current buffer size just after it has been sent. Therefore, its buffer information is not up-to-date, and it must wait until the end of the next frame to transmit it. At this time, the information in its buffer has long changed, and accordingly the resources allocated to it by the central control point should be insufficient, and only the next frame will be requested more. Therefore, this results in a very uneven distribution of resources to individual users. Even from long-term statistics, the resources obtained are similar to those of other users. As their messages are often delayed, the quality of service will be degraded. Summary of the invention

In view of the above problems, the present invention has been made. SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and corresponding control device for improving fairness in a time division multiplexed wireless system to avoid degradation of the quality of service at the subscriber end.

In an aspect of the invention, a method for improving fairness in a time division multiplexed wireless system is provided, comprising the steps of: allocating a time slice to each of a plurality of users in a predetermined order in a frame; and in said frame The subsequent frames are rotated into the order of the time slices allocated by the respective users.

• According to an embodiment of the invention, in the method, every predetermined number of frames is rotated into the order of the time slices allocated by the respective users.

According to an embodiment of the present invention, in the method, the order of time slices allocated to the respective users is clockwise.

According to an embodiment of the present invention, in the method, the order of time slices allocated to the respective users is reversed in a counterclockwise direction.

According to an embodiment of the present invention, in the method, before the rotation of the time slice, the time slice of each user is calculated and allocated by a predetermined algorithm in accordance with the request of each user.

According to an embodiment of the invention, in the method, the frame is a medium access control frame.

In another aspect of the present invention, a control device for use in a time division multiplexed wireless system is provided, comprising: an allocation and rotation device for allocating time for each of a plurality of users in a predetermined order in a frame a slice; and an order in which the time slices allocated to the respective users are rotated in frames subsequent to the frame.

According to an embodiment of the present invention, in the control device, the allocating and rotating device includes: an allocating unit, configured to allocate a time slice to each of the plurality of users in a predetermined order in the frame; and a rotation unit, And the order in which the time slices allocated to the respective users are rotated in frames subsequent to the frame.

According to an embodiment of the present invention, in the control device, the method further includes: a radio frequency device, configured to receive/transmit a wireless signal from/to the user end; and a baseband device, configured to: and a frame from the distribution and rotation device The wireless signal received by the radio frequency device is subjected to baseband processing.

According to an embodiment of the present invention, in the control device, every predetermined number of frames is rotated into an order of time slices allocated by the respective users. According to an embodiment of the present invention, in the control device, the order of time slices allocated to the respective users is clockwise.

According to an embodiment of the present invention, in the control device, the order of time slices allocated to the respective users is reversed in a counterclockwise direction.

According to an embodiment of the present invention, in the control device, the allocating unit calculates and allocates a time slice of each user by a predetermined algorithm in accordance with a request of each user.

According to an embodiment of the invention, in the control device, the frame is a medium access control frame.

With the above configuration of the present invention, it is possible to improve the fairness of the time slice allocated to each user when providing services for a plurality of users at the same time, thereby avoiding degradation of the quality of service of some users. DRAWINGS

1 is a schematic structural diagram of a MAC frame used in a TDMA radio system;

2 is a block diagram showing the structure of a TDMA wireless system according to an embodiment of the present invention;

Figure 3 shows a functional block diagram of a control point 100 in accordance with an embodiment of the present invention as depicted in Figure 2; Figure 4 is a flow diagram of a method of performing the present invention in a TDMA wireless system in accordance with an embodiment of the present invention; A block diagram of the configuration of the distribution and rotation portion 31 shown in FIG. 3;

Fig. 6 shows a comparison curve of QoS parameters in the case of a fixed user order and the order of rotating users. detailed description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to Figs.

2 is a block diagram showing the construction of a TDMA wireless system in accordance with one embodiment of the present invention. As shown in FIG. 2, a TDMA wireless system according to an embodiment of the present invention includes a control point 100 and a user 1, a user 2, a user 3, a user 4, a user 5, and a user 6. The control point 100 allocates resources such as time slices to respective users at the request of respective users, and wirelessly transmits wireless signals to individual users or receives wireless signals from respective users.

Figure 3 shows a functional block diagram of a control point 100 in accordance with an embodiment of the present invention as described in Figure 2. As shown in FIG. 3, the control point 100 includes a radio frequency section 10, a baseband section 20, a MAC (Media Access Control) module 30, and a packet processing section 40.

The radio frequency section 10 receives/transmits wireless signals from/to individual users. Baseband section 20 for RF The wireless signal received by the portion 10 is subjected to baseband processing, and the processed signal is transmitted to the MAC module 30. At the MAC module 30, the allocation and rotation section 31 calculates and allocates a time slice for each user according to the request of each user, sets the relative position of the user in the MAC frame, and performs rotation in accordance with a predetermined criterion.

For example, the control point issues a beacon at the beginning of each frame, including the length of the time slice allocated to each user, the position in the frame, and various synchronization control information. For example, user 1, user 2, user 3, user 4, user 5, and user 6 are assigned respective time slices, and the time slices of each user are set in the order of 1, 2, 3, 4, 5, and 6 in the MAC. The position in the frame.

Next, the control point transmits data from the packet processing section 40 to each user to transmit or receive data transmitted by each user based on the allocated time slice in the data body portion of the frame. The control point accepts the next frame resource request message sent from each user at the end of each frame or other location, that is, the time slice length required to request the next frame.

After the control point receives the resource request message of each user, according to the request of each user, each user is assigned a corresponding algorithm by using a scheduling algorithm, such as SRPT (Shortest Remaining Processing Time), WFQ (Weighted Fair Queue), and the like. The length of the time slice.

After the time slice is calculated, the control point performs a rotation sequence operation according to the current position of each user in the MAC frame. That is, after the next frame or a predetermined number of frames, the allocation and rotation portion 31 is in the order of moving one bit, that is, 2, 3, 4, 5, 6, 1 or moving two digits, that is, 3, 4, 5 6, 6, 1, 2 set the position of each user's time slice in the MAC frame, and so on, of course, can also move multiple bits. In this way, each user's delay can be treated fairly.

After the allocation and rotation portion 31 is set, when the next frame arrives, the data from the packet processing portion 40 is transmitted to the user in the time slice of the corresponding position of the set MAC frame, or in the next frame, in the set The wireless signal of the user is received in a time slice of the corresponding position of the MAC frame.

4 is a flow diagram of a method of performing the present invention in a TDMA wireless system in accordance with an embodiment of the present invention. As shown in Fig. 4, in step S110, the allocation and rotation section 31 arranges the user time slices in the frame η, η+1 ···, η+Ν_1 in a certain order, for example, in ascending or descending order of the user number.

Specifically, the control point issues a beacon at the beginning of each frame in the frame η, η+l···, η+Ν-1, including the length of the time slice allocated to each user, the position in the frame, and various Synchronize control information, etc. For example, user 1, user 2, user 3, user 4, user 5, and user 6 are assigned respective time slices, and the time slices of each user are set in the order of 1, 2, 3, 4, 5, and 6 in the MAC. The position in the frame.

Next, according to the allocated time slice, the data body portion in the frame will come from the packet processing portion 40. The data is sent to each user to send or receive data sent by each user. The control point accepts the next frame resource request message sent from each user at the end of each frame or other location, that is, the time slice length required to request the next frame.

After the control point receives the resource request message of each user, according to the request of each user, each user is assigned a corresponding algorithm by using a scheduling algorithm, such as SRPT (Shortest Remaining Processing Time) and WFQ (Weighted Fair Queue). The length of the time slice.

In step S120, the allocation and rotation portion 31 rotates the user time slice in the frame order in the frame n state, for example, shifting the above-described order to the left or right by one or more bits, that is, in the clockwise or counterclockwise direction. Rotate the position of each user's time slice. Then, the beacon transmission is performed and the data of each user is transmitted in the order after the above-described rotation.

Although the functions of the distribution and rotation section 31 have been described above in the form of specific examples, the present invention is by no means limited thereto. For example, the distribution and rotation portion 31 can be configured as an allocation unit 311 and a rotation unit 312 to implement the above functions, as shown in FIG.

Fig. 6 shows a comparison curve of QoS parameters in the case of a fixed user order and the order of rotating users. As shown in Fig. 6, the curve marked with the diamond node is the Job Failure Rate (JFR) of the fixed user order, where JFR refers to the proportion of the message that fails to meet the delay requirement. The serial number of the user's time slice in the frame is 1, 2, 3, 4, 5, 6. The curve marked with a rectangular node is the result obtained in the case of rotating the user order. The average JFR of the six users is about 13%, but we can see that the fairness after using the rotation order is much better. That is, while improving the fairness of users, the quality of service is not lowered.

The above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope of the present disclosure. All should be covered by the scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

What is claimed is: 1. A method of improving fairness in a time division multiplexed wireless system, comprising the steps of: allocating a time slice to each of a plurality of users in a predetermined order in a frame;

The order of the time slices allocated to the respective users is rotated in the frame following the frame.

2. The method of claim 1 wherein every predetermined number of frames is rotated into an order of time slices allocated by said respective users.

3. A method as claimed in claim 2, characterized in that the order of time slices assigned to said respective users is clockwise.

4. The method of claim 2, wherein the order of the time slices assigned to the respective users is reversed in a counterclockwise direction.

begging

The method according to claim 2, characterized in that, before the rotation of the time slice, the time slice of each user is calculated and distributed by a predetermined algorithm according to the request of each user.

6. Method according to one of claims 3 to 5, characterized in that the frame is a medium access control frame.

7. A control device for use in a time division multiplexed wireless system, comprising:

An allocation and rotation means for allocating a time slice to each of the plurality of users in a predetermined order in the frame, and rotating the order of the time slices allocated to the respective users in the frame subsequent to the frame.

8. The control device according to claim 7, wherein the allocating and rotating device comprises: an allocating unit, configured to allocate a time slice to each of the plurality of users in a predetermined order in the frame;

A rotation unit, and a sequence of time slices allocated to the respective users in a frame subsequent to the frame.

9. The control device of claim 8, further comprising:

a radio frequency device for receiving/transmitting a wireless signal from/to the user terminal;

A baseband device for performing baseband processing on a frame from the distribution and rotation device and a wireless signal received by the radio frequency device.

10. The control device according to claim 9, wherein every predetermined number of frames is rotated into an order of time slices allocated by said respective users.

A control apparatus according to claim 10, wherein the order of time slices allocated to said respective users is clockwise.

The control device according to claim 10, wherein the order of the time slices allocated to said respective users is reversed in a counterclockwise direction.

The control device according to claim 10, wherein the allocating unit calculates and allocates a time slice of each user by a predetermined algorithm in accordance with a request of each user.

The control device according to any one of claims 9 to 13, wherein the frame is a medium access control frame.