WO2004086660A1

WO2004086660A1 - A method about data tranmission of a tdd mobile communication system

Info

Publication number: WO2004086660A1
Application number: PCT/CN2003/001156
Authority: WO
Inventors: Yuehua Chen; Lei Zhou; Hao Hu; Sha Ma; De Chen
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2003-03-26
Filing date: 2003-12-31
Publication date: 2004-10-07
Also published as: AU2003292877A1

Abstract

The present invention disclosed a method about data transmission of a TDD mobile communication system. Using for high-speed data transmission between user’s terminal and network in TDD mobile communication system. The method comprises: in the system, set the transmission period of time that corresponds to the invariable count physical layer subframe as a transmission periods, and set time slot resource using for transmit upstream information and downstream information according to invariable proportion in each subframe. During transmission user’s data, place the common control information in each invariable period of each transmission periods in network side, use all the data part that in all subframe downstream time slot resource of the invariable period transmit the common control information. The method of the present invention based on TDD technology, realization high-speed and more efficient and better quality in data service, and could fulfil the requirement of communication development in the future.

Description

Data transmission method for time division duplex mobile communication system

The present invention relates to data transmission technology of a mobile communication system, and particularly to a time division duplex

(TDD) Data transmission method for mobile communication system. Background of the invention

The wireless mobile communication system has evolved from a frequency division multiple access (FDMA) analog communication system to the current third-generation mobile communication system. Supported services have evolved from pure voice services to current data and voice mixed services, to high-speed data. business. People's requirements for communication systems are getting higher and higher, and they are no longer satisfied with accessing the network through computers at home. Instead, they want to be able to receive data services such as sending e-mails and performing web browsing at any place. Therefore, the development of communication systems has gradually evolved from a system that only serves voice to a system that supports high-speed data. In the third generation of mobile communication standards, some standards use the TDD system. The characteristics of the TDD system are that the uplink and downlink are in the same frequency band and do not need paired frequencies. Therefore, the spectrum utilization is high and the correlation between uplink and downlink resources is large. These have great advantages over frequency division duplex (FDD) systems.

The physical layer frame structure of the TDD system is shown in FIG. 1 and FIG. 2. FIG. 1 is a schematic diagram of a frame structure of a physical layer of the prior art TDD system, and FIG. The physical layer frame of the TDD system adopts a three-layer structure: radio frame, sub-frame, and time slot. Each radio frame has a frame length of 10 ms, and it includes two subframes with a frame length of 5 ms. Each subframe contains seven time slots of time slots 0 to 6, and at the same time, as shown by the hatched part, There are three special time slots between time slot 0 and time slot 1: downlink pilot time slot (DwPTS), guard time slot (GP) and uplink pilot time slot (UpPTS), of which downlink pilot time slot and uplink pilot time slot Frequency slots are used for synchronization.

In the physical layer frame of the TDD system, time slot 0 is fixedly allocated as the downlink time slot, and time slot 1 is fixed. That is, uplink and downlink time slots can be dynamically allocated. In FIG. 2, all time slots 2 to 6 are allocated as downlink time slots. The physical channel structure of the downlink slot and the uplink slot is the same, and both are bursts. A burst is transmitted in a time slot. The structure of each burst is shown in FIG. 6, which includes a data part 1, an intermittent pilot part, and a data part 2.

In the downlink burst, control information for uplink transmission such as power control information (TPC) and synchronization adjustment information (SS) is also included between the intermittent pilot part and the data part 2. Power control information and synchronization adjustment information need to be dug out of the user's service time slot resources for transmission of these signalings, that is, they need to occupy a part of the user's data resources and be spread and modulated together with the data.

In addition, the TPC position of the uplink time slot is the same as the TPC position of the downlink time slot. The downlink time slot uses a spreading factor of 16. A user only occupies one or more code channels, and each user is code division multiplexed in a time slot. The spreading factors used in the uplink are 1, 2, 4, 8, and 16, and each user is also code division multiplexed in the same time slot. A physical signal in a time slot is a burst. A transmitter can transmit several bursts at the same time. In this case, the data part of several bursts must use different spreading codes.

In the TDD system, different user signals are collectively distinguished by the time domain and the code domain. That is, the difference between users is to use the spreading code of their own user data.

The radio frame allocation in TDD mode can be continuous, that is, the time slot of each frame can be allocated to the physical channel, or it can be discontinuously allocated, that is, only the time slots in some radio frames are allocated to the physical channel.

In the TDD system, most of the common control information is delivered through the 0th and 1st code channels of the 0th time slot.

The uplink and downlink resources are temporarily allocated to the user for use by the system, and the allocated resources do not change during the communication process. At the end of the communication, the user will occupy the resources freed.

In summary, the physical layer structure characteristics of TDD mainly include:

1. The allocation of uplink and downlink time slots is dynamic;

2. The sharing relationship between user communication resources is time division plus code division, and multiple users have a code division relationship in a certain time slot;

3. Broadcast information is transmitted in a fixed time slot of each subframe;

4. The uplink control resources such as power control information and synchronization adjustment information use user data resources;

5. During the user's communication, the resources allocated by the system to the user will not change. According to the above description, it can be seen that the characteristics of the TDD system are good for voice services. However, if data and voice services are transmitted at the same time, they will affect each other: because the quality of service (QoS) of data and voice is very different, the real-time nature of voice services is strong, but the bit error rate is not high For the non-real-time service of the data service, the requirement for the bit error rate is very high. In order to achieve this, a compromise must be made between the two. For example, the following methods are used for data transmission in TDD:

A dedicated transmission channel High Speed Downlink Shared Channel (HS-DSCH) is set up for transmitting high speed data services. This channel is a shared channel. When the network side sends data to a user, multiple such HS-DSCH channels can be used, and these channels are arbitrary codes that can be in multiple time slots. In addition, there is a high-speed shared control channel (HS-SCCH) corresponding to the HS-DSCH channel to notify the user to which user the HS-DSCH channel sent later.

However, the above method additionally requires a control channel to transmit control information to the user, and these channels must require high transmission quality, and this requirement causes problems such as limited signal transmission distance to the system. In addition, in the process of transmitting data, the transmission quality of voice must also be guaranteed. Different transmission quality requirements cause the system's working capacity to be limited. And this method does not make Users are satisfied with the efficiency of data and voice transmission. As the user's continuous enhancement of data services makes the requirements for communication systems higher and higher, and data services are the inevitable direction for the development of communication services in the future, it is necessary to find ways to meet users' needs for data services. Summary of the invention

In view of this, the object of the present invention is to provide a data transmission method for a time division duplex (TDD) mobile communication system. Based on the TDD technology, it realizes high-speed, efficient and high-quality data services to meet future communication development needs. .

'In order to achieve the above objective, the technical solution of the present invention is specifically implemented as follows:

A data transmission method for a time division duplex (TDD) mobile communication system is used for high-speed data service transmission between a user terminal and a network side in a time division duplex (TDD) mobile communication system. The method is:

In the system, a transmission period corresponding to a fixed number of physical layer subframes is set as a transmission period, and a time slot resource for transmitting uplink and downlink information is set according to a fixed ratio in each subframe. In the process of transmitting user data, the network side All the downlink common control information is concentrated in a fixed period of each transmission cycle, and the data portion of all downlink slot resources of all subframes in the fixed period is used for transmission.

The method may further include: allocating all downlink service time slot resources of each subframe to a user terminal in a subframe transmitting service information of the user terminal.

The method may further include: setting timeslot 1, timeslot 2, and timeslot 3 in each subframe to transmit uplink information fixedly; and timeslot 0, timeslot 4, timeslot 5, and timeslot 6 in each subframe Downlink information is fixedly transmitted.

The user terminal may further obtain the downlink time slot resource by receiving the subframe: downlink data including service data or common control information of a single user terminal, an intermittent pilot sequence, and a network side for adjusting each user terminal when transmitting uplink information Required uplink control Information, the three pieces of information are time-multiplexed in the same subframe.

The user terminal can measure the channel condition according to the obtained intermittent pilot sequence to obtain the downlink data transmission rate. ,

The method may further include: the user terminal distinguishes service data of the user terminal from public control information by detecting a preamble sequence before a downlink data packet of each subframe, and distinguishes service data of different user terminals.

The user terminal may further obtain reverse power control information and uplink synchronization adjustment information through the obtained uplink control information; according to the power of the reverse power control information and the time indicated by the uplink synchronization adjustment information, the user terminal passes the uplink of the subframe The time slot resource transmits a data rate instruction required for downlink transmission to the network side.

The user terminal may further obtain the uplink service time slot resource allocation situation through the obtained uplink control information; the user terminal may obtain the available uplink service time slot resource according to the uplink service time slot resource allocation situation. '

The method may further include: the user terminal transmits uplink transmission control information to the network side in time slot 1, and transmits user uplink transmission service data to the network side in time slot 2 and time slot 3.

When transmitting the uplink transmission control information, the user terminal can further transmit the downlink data rate control information and the uplink resource request information including the downlink transmission data rate instruction; during the data transmission process, the user terminal only uses the current data rate and the data to be transmitted by the user. And the maximum rate that the user terminal can support to transmit uplink transmission control information to the network side. The network side controls the uplink transmission control information and the current data rate of each user, the uplink slot resource usage, and its own load. The uplink service time slot resources that can be used by the user terminal are adaptively adjusted. The downlink data rate control information is obtained by the user terminal by measuring the channel quality of one or more subframes. '

When transmitting the uplink transmission control information, the user terminal may further transmit confirmation information indicating that the downlink data packet is correct to the network side after receiving the data packet. The time slot resource for transmitting uplink transmission service data may be time-division multiplexed or code-division multiplexed among more than one user.

The time slot resource for transmitting uplink transmission control information may be code division multiplexed among more than one user.

The method may further include that during the data transmission process, the network side uses a joint detection technique to demodulate the received uplink transmission control information.

The downlink common control information may include cell broadcast information, user paging information, and user forward access information.

As can be seen from the technical solution of the present invention, the data transmission method of the TDD mobile communication system of the present invention only needs to perform fixed allocation and corresponding processing on the uplink and downlink time slots of the frame structure, and does not need to add an additional control channel. On the basis of TDD technology, high-speed, efficient and high-quality data services are realized, which can meet future communication development needs. Brief description of the drawings

FIG. 1 is a schematic diagram of a physical layer frame structure of a prior art TDD system;

FIG. 2 is a schematic diagram of a prior art subframe slot allocation structure;

3 is a schematic diagram of a transmission cycle according to a preferred embodiment of the present invention;

FIG. 4 is a schematic diagram of a subframe slot allocation structure in the embodiment shown in FIG. 3; FIG.

5 is a schematic diagram of a subframe structure in the embodiment shown in FIG. 3;

FIG. 6 is a schematic diagram of a burst structure in the prior art. Mode of Carrying Out the Invention

In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention is further described in detail below with reference to the embodiments and the accompanying drawings.

The data transmission method of the present invention is used for a pure data service of a TDD mobile communication system, This method does not need to change the existing method for receiving and sending the subframes by the user terminal and the network side, and only needs to perform fixed allocation and corresponding processing on the uplink and downlink time slots of the subframe structure.

Referring to FIG. 3, FIG. 3 is a schematic diagram of a transmission cycle according to a preferred embodiment of the present invention. In this embodiment, according to the data service transmission quality requirements, the subframes of the 128 TDD mobile communication system physical layer data frames are set as a transmission period, and the network side transmits the downlink control information in a concentrated manner through the last 8 subframes in the transmission period.

In the transmission period shown in FIG. 3 of the present invention, the uplink resources and the downlink resources are time-multiplexed to the frame, and the allocation ratio of the time slots in the uplink and downlink resources is fixed. The reason is that in communication systems, from the perspective of statistical probability, the proportion of uplink and downlink traffic is relatively fixed. Therefore, the fixed allocation of uplink and downlink resources reduces the process of uplink and downlink resource allocation and reduces interference.

Referring to FIG. 4, FIG. 4 is a schematic diagram of a subframe slot allocation structure in the embodiment shown in FIG. As shown in FIG. 4, in this embodiment, the uplink and downlink resources in each subframe are fixed and allocated according to the following ratios: timeslot 1, timeslot 2, and timeslot 3 are fixed transmission uplink resources; timeslot 0, timeslot 4, Time slot 5 and time slot 6 fixedly transmit downlink resources. In the process of transmitting user data, all downlink sources in the subframe are allocated to the same user terminal; when transmitting downlink control information, all downlink resources are used to transmit the downlink control information. The uplink resource time slot 1 is set as the uplink transmission control part, and time slot 2 and time slot 3 are set as the uplink transmission service part; the user terminal transmits uplink transmission control information to the network 4 in the time slot 1 and is sent to The network side transmits the user's uplink transmission service information.

Referring to FIG. 5, FIG. 5 is a schematic diagram of a subframe structure in the embodiment shown in FIG. 3. Each time slot in the above-mentioned D-line resource also includes a downlink data (Data) part, an uplink control robustness (ULC), and an intermittent pilot sequence (Mid). These three parts are time-division multiplexed in one frame. The downlink data part can realize the transmission of user service data and public control information. Time division multiplexing between sub-frames. The present invention adopts a Turbo code for data transmission. The Turbo code is an iterative convolutional code. Its data block has the best performance between lk and 4k. In order to fully take advantage of the Turbo code, it is necessary to find a suitable data block length. Only all the service time slots in a sub-frame are allocated to a user terminal, which increases the downlink transmission power for a certain user while eliminating interference to other users. The ULC includes control information for adjusting the uplink data transmission of the user terminal on the network side, and the code division ULC between each user terminal. The user terminal measures the channel condition by using the obtained Mid sequence to achieve an estimation of the channel condition, and obtains a downlink data transmission rate. The time division multiplexing of the Mid sequence and the Data also reduces the interference to the Data.

In this embodiment, a preamble sequence is added before the downlink data block of time slot 4 in each subframe described above, and the user terminal discriminates user terminal service data and public control information according to the preamble sequence. And differentiating the business data of different user terminals. Of course, according to the present invention, the preamble sequence may also be set in other downlink time slots, for example, in time slot 1. The advantage of this is that: no additional signaling is required to notify a user whether it has its information, because it will cost a lot to properly notify the user, which will affect the transmission of user business data.

At the same time, the ULC in the above downlink resources not only includes reverse power control information (TPC) and uplink synchronization adjustment information (SS); moreover, the ULC also includes uplink resource allocation signaling. The user terminal adjusts the transmission power according to the TPC and the transmission time according to the SS, and transmits the downlink data rate instruction to the network side through the uplink resources of the subframe. Both TPC and SS are used to control the uplink transmission conditions of the user equipment. As shown in FIG. 5, each time slot of the downlink resource in this embodiment includes two ULC parts, one ULC can be used for TPC, and the other can be used for transmission of SS, which can prevent insufficient resources. The user terminal obtains the allocation situation of the uplink service resource through the uplink resource allocation signaling; and obtains the available uplink service resource according to the allocation signaling. In this way, dynamic allocation of uplink service resources can be achieved, thereby achieving efficient use of resources. The above ULC is time-division multiplexed with Data in the sub-frame, so that interference with service data is reduced, and a higher transmission power can be used, thereby improving the quality of data transmission. the amount.

In order to facilitate the user terminal to the common control information including the cell broadcast, paging, and access information that the user needs to use, the above information may be sent in consecutive multiple frames starting from a fixed position, or the above information may be sent in a fixed interval frame. This embodiment sends the common control information in the last 8 frames. If a time slot is used to transmit a channel such as a broadcast channel (BCH), a forward access channel (FACH), and multiple users share the time slot, the connection requirements of these channels are not the same. The inter-symbol interference increases, so that users on the edge of the cell or with poor channel shields cannot obtain the necessary control information, which reduces the efficiency of the system. Therefore, this embodiment adopts a method for transmitting common control information at a fixed location.

As shown in FIG. 5, in this embodiment, the uplink resource slot 1 is set as an uplink transmission control part, and time slots 2 and 3 are set as uplink transmission service parts; the uplink transmission control information transmitted in slot 1 may include The downlink data rate control information and uplink resource request information of the downlink data rate instruction; during the data transmission process, the user terminal transmits uplink transmission control information to the network side through time slot 1 according to the current data rate and uplink resource conditions, and the network side according to the The uplink transmission control information and the current data rate and uplink resource conditions are used to adaptively adjust uplink service resources. Because this system is link-adaptive, users must transmit related information to the network side, so this downlink data rate control information is essential. Request information using uplink resources In order to make full use of uplink resources, users must report relevant information to the network side.

When uplink transmission control information is transmitted in time slot 1, the downlink data block confirmation information (ACK) transmitted to the network side in time slot 1 may also indicate the correctness of the downlink data packet transmission. The transmission of the entire data from the network side to the user, to the user judging whether the data transmission is correct or not, and the user to feedback the judgment result is a complete process. In order to achieve reliable data transmission, retransmission of incorrectly transmitted data blocks is necessary to achieve a high transmission shield. Therefore, for users with data block transmission, it is necessary to reserve the transmission position for ACK information. Uplink transmission control information in time slot 1 Within each user, code division multiplexing is required. During data transmission, the network side uses a joint detection technique to demodulate the received uplink transmission control information. The joint detection technology refers to the data of multiple user terminals multiplexed on the same time slot, and there is correlation between them. Therefore, the data of other user terminals is not simply discarded, but demodulated together, and then selected. The data of the required user terminal is output there. This will ensure transmission quality.

In addition, the uplink transmission service information in timeslots 2 and 3 can be time-division multiplexed or code-division multiplexed among multiple users; the uplink transmission control information in timeslot 1 can be code-division multiplexed among multiple users. The uplink data transmission resources in time slot 2 and time slot 3 may be code division multiplexing, and the uplink resource request instruction in the uplink control information in time slot 1 not only provides the possibility of user dynamic uplink rate realization, but also makes full use of Upstream resources.

The process of data transmission between the user terminal (UE) and the network using the subframe structure shown in FIG. 4 is:

1. After receiving a frame, the UE measures the channel condition according to the Mid discontinuous pilot sequence obtained from the frame or other multi-frames, and obtains a downlink transmittable data rate (DR).

2. After receiving the TPC and SS in the ULC, the UE sends a DR instruction to the network side according to the power adjustment amount indicated by the TPC and the time indicated by the SS.

3. The network side receives the DR instruction, performs scheduling, and adds a preamble pilot sequence before the user data packet, and then sends a data packet of the UE in the Data part shown in FIG. 4.

4. After receiving the data packet, the UE performs a CRC check to see whether the data is correct. If the data is correct, it sends ACK signaling in the uplink control slot, otherwise it sends NACK signaling.

5. After receiving the ACK signaling, the network side will schedule another new data packet to the UE, and if receiving the NACK signaling, retransmit the erroneous data packet.

6. If the UE has uplink data transmission, it transmits data in the uplink service time slot. If the UE finds that the data rate transmitted by the network side is lower than its expected value, the user will transmit an uplink resource request indication through the uplink control information to inform the network Side it has higher speed to begging.

7. After receiving the uplink resource request signaling, the network side will indicate whether the user has obtained the required uplink resources in the ULC domain according to the uplink service status and channel conditions of all users in the cell.

.8. When the system has broadcast information and user control information to be transmitted, the common control information may be transmitted once within a certain period, such as 640ms, that is, 128 frames in this embodiment. Among them, the time for transmitting public control information is 40ms of downlink resources, that is, 8 frames of 5ms.

It can be seen from the foregoing embodiments that the data transmission method of the TDD mobile communication system of the present invention only needs to perform fixed allocation and corresponding processing on the uplink and downlink timeslots of the frame structure, and does not need to add an additional control channel. On the basis of TDD technology, high-speed, efficient and high-quality data services are realized, which can meet future communication development needs.

The above description is only the preferred embodiments of the present invention, and is not intended to limit the protection scope of the present invention.

Claims

Claim

1. A data transmission method for a time division duplex (TDD) mobile communication system, which is used for high-speed data service transmission between a user terminal and a network side in a time division duplex (TDD) mobile communication system, and is characterized in that the method is :

2. The data transmission method according to claim 1, further comprising: allocating all downlink service time slot resources of each subframe to a user terminal in a subframe in which service information of the user terminal is transmitted. .

3. The data transmission method according to claim 1 or 2, wherein the method further comprises: setting time slot 1, time slot 2, and time slot 3 in each subframe to transmit uplink information fixedly; and each subframe Time slot 0, time slot 4, time slot 5 and time slot 6 in the frame transmit downlink signals fixedly

4. The data transmission method according to claim 1, wherein: the user terminal further obtains, by receiving downlink subframe resources of the subframe, downlink data and intermittent pilot sequences including service data or common control information of a single user terminal. And the network side is used to adjust uplink control information required by each user terminal when transmitting uplink information, and the three pieces of information are time-division multiplexed in the same subframe.

The data transmission method according to claim 4, characterized in that: the user terminal measures a channel condition according to the obtained intermittent pilot sequence to obtain a downlink data transmission rate.

6. The data transmission method according to claim 4, further comprising: The method includes: the user terminal distinguishes service data and public control information of the user terminal by detecting a preamble sequence before a downlink data packet of each subframe, and distinguishes service data of different user terminals.

7. The data transmission method according to claim 4, wherein: the user terminal further obtains reverse power control information and uplink synchronization adjustment information through the obtained uplink control information; and the power according to the reverse power control information The time indicated by the adjustment information is synchronized with the uplink, and the user terminal transmits the data rate instruction required for the downlink transmission to the network side through the uplink slot resources of the subframe.

8. The data transmission method according to claim 4, characterized in that: the user terminal further obtains the allocation situation of the uplink service time slot resource through the obtained uplink control information; the user terminal according to the allocation of the uplink service time slot resource The situation results in the available uplink service time slot resources.

9. The data transmission method according to claim 3, further comprising: transmitting, by the user terminal, uplink transmission control information to the network side in time slot 1, and transmitting the user's data to the network side in time slot 2 and time slot 3. Upstream transmission of service data. '

10. The data transmission method according to claim 9, wherein: when transmitting the uplink transmission control information, the user terminal further transmits downlink data rate control information and uplink resource request information including a downlink transmission data rate instruction; during data transmission In the process, the user terminal transmits uplink transmission control information to the network side according to the current data rate, the amount of data to be transmitted by the user, and the maximum rate that the user terminal can support, and the network side ^^ according to the uplink transmission control information and the current data rate of each user The usage of the uplink time slot resources and its own load are adjusted.

11. The data transmission method according to claim 10, wherein the downlink data rate control information is obtained by a user terminal by measuring a channel shield amount of one or more subframes.

12. The data transmission method according to claim 9 or 10, characterized in that: when the user terminal transmits the uplink transmission control information, after receiving the data packet, it further transmits a confirmation to the network side to indicate the correctness of the transmission of the downlink data packet. information.

13. The data transmission method according to claim 9, wherein: the time slot resource for transmitting uplink transmission service data is time-division multiplexed or code-division multiplexed among more than one user.

14. The data transmission method according to claim 9, wherein: the time slot resource for transmitting uplink transmission control information is code division multiplexed among more than one user.

15. The data transmission method according to claim 14, further comprising: during the data transmission process, the network side uses a joint detection technique to demodulate the received uplink transmission control information.

16. The data transmission method according to claim 1, wherein the downlink public control information includes cell broadcast information, user paging information, and user forward access information.