KR20030029310A - Method for transporting control information to dsch in a mobile communication system - Google Patents

Abstract

PURPOSE: A method of transmitting control information for a downlink shared channel in a mobile communication system is provided to control dedicated channels where the control information is loaded, according to states of the dedicated channels transmitting the control information, thereby enhancing transmissions for an HI(HS-DSCH(HSDPA Downlink Shared Channel) Indicator) and a shared control channel loading the control information. CONSTITUTION: When a mobile station enters a handover region(81), a target base station of handover decides whether to transmit control information on an HS-DSCH with an HSDPA(High Speed Downlink Packet Access) method through dedicated channels(82). If so, the target base station transmits the control information on the HS-DSCH supplied from a current base station of a target mobile station(83). The target base station receives the control information through a control station or the current base station receives the control information, since the control information on the HS-DSCH has to be exchanged.

Description

Method of transmitting control information for downlink shared channel in mobile communication system {METHOD FOR TRANSPORTING CONTROL INFORMATION TO DSCH IN A MOBILE COMMUNICATION SYSTEM}

The present invention relates to a method of transmitting control information in a high speed downlink packet access (HSDPA) system that promotes standardization in 3GPP. In particular, a conventional downlink shared channel (DSCH) is performed during soft handover in a 3GPP system. The present invention relates to a forward control signaling method for supporting an extended HS-DSCH (HSDPA Downlink Shared Channel).

More specifically, the present invention transmits the control information and HI (HS-DSCH Indicator) which is one of the control information at the current base station or the target base station to support the HS-DSCH when the UE is in the soft handover state. When all target base stations are capable of HI and shared control channel transmission, all target base stations transmit the control information to the mobile station to increase the reliability of the control information, and only some target base stations share the HI. When the control channel can be transmitted, the HI and the shared control channel are transmitted by allocating an elevated transmit power value (Power offset) to the target base station which can transmit the control channel.

On the other hand, if the target base station is unable to transmit the HI and the shared control channel, and transmits the HI and the shared control channel by allocating an increased transmission power value (Power offset) to the current base station.

Hereinafter, the prior art will be described.

First, a general background of the prior art and the present invention will be described.

ETSI, Japan of Europe for drafting detailed specifications of the third generation Global System for Mobile Communication (GSM) network and W-CDMA (asynchronous) access technology and terminal specifications based on the same. National or regional standardization bodies such as ARIB / TTC, T1 in the United States and TTA in Korea have formed a combination called the Third Generation Partnership Project (hereinafter abbreviated as 3GPP). A third generation mobile communication system (IMT-2000) is being developed that can provide multimedia services such as video and data in a wireless environment.

Regarding international telecommunication standards, the authority to establish standards rests with the International Telecommunication Union (ITU), a body of the United Nations.

The 3GPP is oriented towards international standards, and has proposed its IMT-2000 standard to the International Telecommunication Union (ITU) separately from other combinations, 3GPP2, and the name of the radio access technology in the standard is W-CDMA. In the European ETSI, the IMT-2000 technical standard is called UMTS (Universal Mobile Telecommunication System) by combining both a network and a wireless access technology.

3GPP supports the activities of five Technical Specification Groups (hereinafter abbreviated as TSG) for fast and efficient project operation and technology development, and each TSG has a set of standards related to the assigned area. Responsible for development, approval, and management.

Among them, the Radio Access Network (hereinafter, abbreviated as RAN) group aims to define a new radio access network in the third generation mobile communication system, and the terminal and UMTS Terrestrial Radio Access Network (hereinafter abbreviated as UTRAN). Develop specifications for the functionality, requirements and interfaces of the

The TSG-RAN Group is again composed of a Plenary Group and four Working Groups. Working Group 1 (WG1) develops standards for the Physical Layer (WG1), while the second Working Group (WG2) works with the Data Link Layer (2nd Layer) and Network Layer (WG2). Role of the third tier). In addition, the third operation group defines standards for interfaces between base stations, radio network controllers (hereinafter referred to as RNCs), and core networks in the UTRAN, and the fourth operation group relates to radio link performance. Discuss requirements and requirements for radio resource management.

1 shows a structure of a radio interface protocol according to a 3GPP radio access network standard.

The radio interface protocol between the user equipment and the UTRAN consists of a physical layer, a data link layer and a network layer horizontally, and vertically transmits a control plane and data information transmission for signaling. It is divided into User Plane.

More specifically, the control plane includes a radio resource control layer (hereinafter referred to as RRC), a radio link control layer (hereinafter referred to as RLC) and a medium. There are Medium Access Control Layer (hereinafter referred to as MAC) and Physical Layer, and in the user plane, Packet Data Convergence Protocol (hereinafter referred to as PDCP) layer, RLC layer, MAC There are layers and physical layers.

The physical layer provides an information transfer service to an upper layer using various wireless transmission technologies. The upper MAC layer is connected through a transport channel, and data between the MAC layer and the physical layer moves through the transport channel. The transport channel is divided into a dedicated transport channel and a common transport channel, respectively, depending on whether the terminal can be used exclusively or shared by multiple terminals.

The MAC layer provides a reassignment service of MAC parameters for allocating and reallocating radio resources. The RLC layer is connected to a logical channel, and various logical channels are provided according to the type of information to be transmitted. In general, a control channel is used for transmitting control plane information, and a traffic channel is used for transmitting user plane information.

The RLC layer provides a radio link establishment and release service. In addition, the RLC performs a segmentation and reassembly function of an RLC Service Data Unit (hereinafter, abbreviated as SDU) from an upper layer of the user plane.

The RLC SDU is delivered to the MAC layer in the form of a PDU after adding header information, which is sized according to the processing capacity in the RLC layer.

The PDCP layer is located above the RLC layer and allows data transmitted through a network protocol such as IPv4 or IPv6 to transmit data in a form suitable for the RLC layer. Also, It reduces unnecessary control information used in the wired network so that it can be efficiently transmitted through the air interface. This feature is called Header Compression and can be used to reduce the amount of header information for TCP / IP as an example.

The RRC provides an information broadcast service that broadcasts information to all terminals located in an arbitrary area. It is also in charge of control plane signal processing for control signal exchange in the third layer, and has a function of setting, maintaining and releasing radio resources between the terminal and the UTRAN. In particular, the RRC has a function of setting, maintaining, and releasing a radio bearer, and allocating, relocating, or releasing radio resources required for radio resource access. In this case, the radio bearer refers to a service provided by the second layer for data transmission between the terminal and the UTRAN. That is, one radio bearer is defined as a process of defining the protocol layer and channel characteristics necessary for providing a specific service and setting each specific parameter and operation method.

In addition, discussions are now being made on technologies that can dramatically increase the transmission speed of downlink, mainly in the second operation group of 3GPP.

The new system is defined as High Speed Downlink Packet Access (hereinafter referred to as HSDPA), and various technologies for supporting voice and high-speed packet data service by developing the function of Release'99, a 3GPP standard, are provided. Proposed and discussed.

The HSDPA system supports the HS-DSCH by extending the capacity and function of a downlink shared channel (DSCH), which is one of transport channels in the Release'99 standard.

2 is a UTRAN structure according to the 3GPP radio access network standard to which the prior art and the present invention is applied.

UTRAN 20 is composed of Node B and RNC as shown in FIG. The Node B is managed by the RNC and serves as an access point of the UTRAN, which receives information sent from the physical layer of the terminal (mobile station) 10 as an uplink, and transmits data to the terminal as a downlink.

The RNC is responsible for the allocation and management of radio resources. The RNC, which is in charge of Node B's direct management, is called Control RNC and is responsible for the management of public radio resources.

A place that manages dedicated radio resources allocated to each terminal is called a serving RNC. The control RNC and the responsible RNC may be the same, but when the UE moves out of the area of the responsible RNC to another RNC, the control RNC and the responsible RNC may be different.

The Radio Network Sub-System (hereinafter referred to as RNS) is composed of one RNC and several Node Bs as shown in FIG. In addition, the RNS in which the responsible RNC is located is called the responsible RNS.

The 3GPP system has a downlink shared channel (DSCH) as a channel for transmitting burst data types.

3 shows a configuration of a DSCH channel.

The DSCH channel is composed of 10ms of radio frames, which can be shared and used by different users in each frame. Also, several users are assigned one node per frame in the root channelization code for the DSCH channel. Can be shared by multiple users.

That is, the DSCH is a code multiplexing and time multiplexing channel shared by several users.

Although the DSCH channel is shared by multiple users, a code with a constant data rate at a moment is used by only one user.

Thus, the DSCH occupied by a specific UE is controlled by the occupied user.

The DSCH necessarily operates in conjunction with the DCH. That is, the user who occupies the DSCH necessarily has a DCH. User Equipment (UE) sends a power control command by measuring the power of the DCH. The DSCH adjusts the power transmitted according to this Transmit Power Command (TPC). That is, the powers of the DCH and the DSCH operate in conjunction.

4 shows the channel structure of the DCH. However, the DCH performs soft handover, whereas the DSCH channel does not perform soft handover.

Therefore, when the DCH is in soft handover and the DSCH is transmitted from only one base station, different power control is required for both.

That is, the DCH generates a TPC by adding powers from several base stations, but since the DSCH channel is transmitted from one base station, power control of the DSCH cannot be performed through power control by the TPC. For this reason, another power control method should be applied to the DSCH channel.

The power control method has already been applied for a number of patents and the description thereof will be omitted.

The above-described HS-DSCH will be described.

The 3GPP system supports high speed packet data service in downlink with HS-DSCH transmission.

To this end, as shown in FIG. 5, a structure of a new transport channel called HS-DSCH and control signalling for it have been proposed.

The HS-DSCH has a short transmission time interval (TTI) (3 slots, 2 ms), unlike the DSCH defined in R'99 / R'4, which is a conventional W-CDMA system standard. It supports various modulation code sets (MCS) that can be used for data rate.

Optimum performance can be obtained by selecting the best MCS for the channel situation.

To this end, hybrid ARQ (HARQ) technology, which combines automatic repeat request (ARQ) technology and channel coding technology, ensures reliable transmission, and up to four users simultaneously through CDMA. It was proposed to support.

As described above, transmission of control information is required for the HS-DSCH, and the information is transmitted through a shared control channel introduced in the HSDPA standard.

For reference, Release 1 and Release 2 are the standard versions for Global System for Mobile Communication (GSM) respectively, and R'99 is the abbreviation of Release 1999, referring to the standard version of 3GPP. , Same as Release 3).

R4 refers to the standard version of 3GPP and is an acronym for Release 4 (released in March 2001, same as Release 2000).

Release 5 is also the version that is currently being standardized.

As shown in FIG. 5, control information can be largely divided into transport format and resource related information (TFRI) and HARQ related information. The TFRI includes information about a transport channel set size, a modulation method, a coding rate, and a number of multi-codes of the HS-DSCH. The HARQ-related information includes a block number (block). number) and redundancy version. In addition, information about a terminal ID (UE identification, UE Id) is transmitted to indicate which user's information. UE Id-related information performs a cyclic redundancy check (CRC) operation together with TFRI and HARQ information to transmit only the resulting CRC.

6 illustrates signaling of a downlink shared control channel for transmitting downlink control information.

As shown in the figure, multiple users can be supported simultaneously, and control information for this uses a shared control channel assigned to each user. The maximum user that can be supported is M = 4.

7 is a diagram illustrating timing of a downlink shared control channel and an HS-DSCH.

As shown in the figure, the HI (HS-DSCH Indicator) is associated with the HS-DSCH, which is transmitted on a dedicated physical channel (DPCH), which indicates that data will be transmitted to the UE through the HS-DSCH. It acts as an indicator for telling in advance.

That is, if the HI bit is determined, the UE can read control information transmitted through a shared control channel and recover HS-DSCH data.

The transmission timing of HI may be variable by one slot interval (0.67 ms), and the HS-DSCH and the shared control channel may have overlapping intervals, the shared control channel is transmitted first, and then the HS-DSCH is Is sent.

In order to reduce the transmission delay, it is possible to transmit as many overlapping intervals of these two channels as possible.

However, in the HS-DSCH operation of the conventional HSDPA system as described above, when the UE (mobile station) is in the handover area, the transmission of HI or shared control channel is not defined.

In general, the high-speed downlink packet access (HSDPA) method aims at a high-speed data service supported by a mobile station with low mobility. However, since the high-speed downlink packet access (HSDPA) method does not assume that there is no handover at all, the mobile station is in a handover area. If the control channel transmission method is conventional, the HI and shared control channel information cannot be obtained smoothly.

In particular, if a target cell to be handed over is an R'99 / R'4 type cell that does not support the HS-DSCH, since the HI or shared control channel does not exist, the current cell does not exist. Since the diversity error cannot be obtained when recovering the transmitted HI and shared control channel information, the reception error increases, which causes a problem in the reliability of the control information regarding the HS-DSCH and causes degradation in the HS-DSCH performance. .

Therefore, in the present invention, when the control information for the downlink shared channel (HS-DSCH) of the high speed downlink packet access scheme is transmitted through a dedicated channel, the control information or control information according to the state of the dedicated channels for transmitting the control information. Control the dedicated channel, and enhance the transmission of the HI and shared control channel carrying the control information for the downlink shared channel (HS-DSCH) of the high-speed downlink packet access method for the downlink shared channel (HS-DSCH) A method of improving reception performance of control information and further improving communication quality of a downlink shared channel (HS-DSCH) is provided.

1 is a view showing the structure of a radio interface protocol according to the 3GPP radio access network standards

2 is a UTRAN structure according to the 3GPP radio access network standards to which the prior art and the present invention is applied

3 shows a configuration of a DSCH channel

4 is a channel structure of a DCH

5 shows a structure of a new transport channel called HS-DSCH and control signalling therefor.

6 is a signaling of a downlink shared control channel for transmitting downlink control information

7 is a diagram illustrating timing of a downlink shared control channel and an HS-DSCH.

8 is a flowchart illustrating an embodiment of a method for transmitting control information for a downlink shared channel for an HS-DSCH of the present invention.

9 is a flowchart illustrating an embodiment of a method for transmitting control information for a downlink shared channel for an HS-DSCH of the present invention.

The present invention relates to a method for transmitting control information in a high speed downlink packet access (HSDPA) system that promotes standardization at 3GPP, an international communication standardization organization, and provides a method of fast downlink packet access at a target base station or a current base station. In the case of transmitting control information for a downlink shared channel (HS-DSCH) through a dedicated channel, the control information or control information is carried according to the state of dedicated channels for transmitting control information such as HI and shared control channel. It characterized in that to control the transmission power of the dedicated channel.

In particular, when the target base station can transmit control information on the downlink shared channel (HS-DSCH) of the high speed downlink packet access method provided by the target base station through a dedicated channel, the high speed downlink packet access provided by the current base station of the target mobile station It is characterized in that to transmit the control information for the downlink shared channel (HS-DSCH) of the scheme.

Further, in this case, it is necessary to exchange control information for the downlink shared channel (HS-DSCH) of the high speed downlink packet access method between the base stations, so that the control station enables the exchange of this control information.

However, each base station may have a different installation standard, and the target base station may not provide a downlink shared channel (HS-DSCH) of a high speed downlink packet access method. Since the control information for the HS-DSCH may not be provided, in this case, it is necessary to increase the output of the control information transmission of the base station that provides the information based on information such as the number of base stations that do not provide the information. It is assumed that at least the current base station of the target mobile station transmits control information on the downlink shared channel (HS-DSCH) of the high speed downlink packet access method provided by the target mobile station.

In this case, the control station makes it possible to exchange this information between base stations, since it is necessary to exchange information on whether to transmit control information for the downlink shared channel (HS-DSCH) of the high speed downlink packet access method. It is done.

In the control information transmission method for the downlink shared channel (HS-DSCH) for the HSDPA of the present invention, if the target base station or the current base station does not transmit the control information for the HS-DSCH, the HS together with the HI and shared control channel The control information may be transmitted by increasing the transmission power of the current base station or the target base station transmitting the DSCH.

Other objects and features of the present invention will become apparent from the detailed description of the embodiments with reference to the accompanying drawings.

Hereinafter, a method of transmitting control information for supporting HS-DSCH according to the present invention will be described with reference to the accompanying drawings.

8 and 9 are flowcharts illustrating embodiments of a method for transmitting control information for a downlink shared channel and a method for controlling power of a control information channel for an HS-DSCH according to the present invention.

First, the overall description and the flow charts will be described once again.

The control information transmission method of the present invention is largely two cases.

First, consider a case in which the target base station supports the HS-DSCH (R5) when the mobile station UE performs soft handover.

If the target base station supports the HS-DSCH (R5), it is possible to transmit the HI and shared control channel that can increase the reliability of the control information.

Therefore, the base station supporting the HS-DSCH in the active set (active base station set) at the time of the soft handover of the mobile station can improve the reliability of control information by allowing both the HI and the shared control channel to be transmitted.

However, even in this case, since the HS-DSCH itself is transmitted by one base station, the HS-DSCH is still transmitted by only one base station because it does not support soft handover. That is, it operates in the hard handover state. In this case, soft handover means that a mobile station makes the same call simultaneously with two base stations participating in the handover for a predetermined time and area, and hard handover means simultaneously the same call with two base stations that one mobile station joins the handover. If you do not do that, you have to disconnect one side of the call to the other side.

On the other hand, even if the target base station (R5) that supports the HS-DSCH, if the base station transmitting the HS-DSCH with the HI and shared control channel to prevent performance degradation when the HI and shared control channel is not sent, the appropriate power Allocate an offset to improve performance.

For this purpose, information related to power offset should be transmitted from the RNC (controller) to the Node B (base station) or from the RNC to another RNC or Node B.

The power offset value may be assigned differently according to a radio link condition to increase efficiency.

As an example of the method of allocating the power offset, the ratio of the target base station transmitting control information for the HS-DSCH through the active set (active base station set) and the DPCH may be reflected in the power increase value.

Second, consider a case where the target base station for soft handover is an R'99 / R'4 base station that does not support the HS-DSCH.

Since the target base station is R'99 / R'4, HI and shared control channel do not exist.

This case is the same as when the base station supports the above-described HS-DSCH but does not transmit the HI and the shared control channel.

Therefore, since the diversity gain is lower than when transmitting from all base stations, the reliability of HI and shared control channel data of the current base station is lowered. Therefore, in order to prevent this, an appropriate power offset value is allocated to the HI and shared control channels of the current base station. It can be improved.

The power offset value should transmit information related to a power offset from the RNC to the Node B or from the RNC to another RNC or Node B. The power offset value may be differently assigned according to a radio link condition to increase power efficiency. Can be.

The present invention described above is summarized as follows.

The present invention is based on the premise that the base station is currently providing data service using the HS-DSCH scheme, and when the mobile station and another base station communicate with the DPCH (when the mobile station is in the Hand over region and the Soft Handover is possible, the mobile station is Can simultaneously receive signals from the current serving base station and another base station)

1) When all target base stations can transmit the control information of the HS-DSCH, the target base station transmits the control information for the HS-DSCH of the current base station through the DPCH, and the mobile station combines these information to gain diversity gain. To get.

2) When only some target base stations can transmit the control information of the HS-DSCH, the ratio of the base station transmitting the control information for the HS-DSCH of the current base station through the active set (active base stations) and the DPCH increases the power. Reflect on the value and transmit it.

3) If all the target base stations do not transmit the control information of the HS-DSCH and the current base station transmits the control information of the HS-DSCH, the transmission power of the channel of the current base station (base station providing the HS-DSCH) control information is increased. Power offset transmits control information for the HS-DSCH through the DPCH.

8 will be described below.

Invention to transmit control information from another base station

When the mobile station enters the handover area (step 81), it is determined whether the target base station of the handover can transmit control information on the downlink shared channel (HS-DSCH) of the high speed downlink packet access method provided by the mobile station through the dedicated channel. (Step 82)

If it is possible to transmit, control information for the downlink shared channel (HS-DSCH) of the high speed downlink packet access scheme provided by the current base station of the target mobile station is transmitted.

In this case, since the control information for the downlink shared channel (HS-DSCH) of the high speed downlink packet access method needs to be exchanged between the base stations, the target base station receives the control information through the control station or directly. do.

9 will be described below.

Invention method for controlling power of control information

In the case where the target base station of the handover uses the same technical standard as described above, the target base station also has an effect by transmitting control information for the downlink shared channel (HS-DSCH) of the high speed downlink packet access method. If the target base station does not support or provide control information for the downlink shared channel (HS-DSCH) of the fast downlink packet access method, the control information for the downlink shared channel (HS-DSCH) of the fast downlink packet access method Since the loss of is expected, it is necessary to increase the power of the channel providing control information for the downlink shared channel (HS-DSCH) of the fast downlink packet access method.

It is determined whether control information for the downlink shared channel (HS-DSCH) of the high speed downlink packet access scheme provided by the current base station is transmitted to the active base stations for the handover that may become the target base station (steps 91 and 92).

1. Some base stations transmit control information

The power of the control information channel of the current base station is increased by an offset (step 93). In this case, the power rise value is determined by comparing the total number of active base stations with the number of base stations transmitting control information.

In addition, if the control becomes complicated, the power of the control information channel of the target base station transmitting the control information may be increased by a certain offset.

2. When all active base stations transmit control information

Power control is not performed according to whether control information of the handover target base station is transmitted.

3. All active base stations do not transmit control information

The power of the control information channel of the current base station is increased by a certain offset (step 94).

Although the preferred embodiment of the present invention has been described above, the present invention may use various changes, modifications, and equivalents. It is clear that the present invention can be applied in the same manner by appropriately modifying the above embodiments.

Accordingly, the above description does not limit the scope of the invention as defined by the limitations of the following claims.

According to the present invention, the control information for the downlink shared channel (HS-DSCH) is received by enhancing the transmission of the HI and the shared control channel carrying the control information for the downlink shared channel (HS-DSCH) of the fast downlink packet access method. It is possible to improve performance and further improve communication quality of HSDPA downlink shared channel (HS-DSCH). In particular, by improving the downlink control signaling method for the HS-DSCH during handover, the performance of the data service of the HS-DSCH can be improved by increasing the recovery performance of the control information.

Claims (8)

A wireless communication system in which a first base station transmits data to a plurality of mobile stations through one communication channel, and transmits control information for the communication channel through a control channel, wherein any one of the plurality of mobile stations is a second base station. And a base station communicating with the mobile station through the control channel, the second base station transmitting data to a plurality of mobile stations through one communication channel, and transmitting control information for the communication channel through the control channel. 2 The base station transmits control information for the communication channel of the first base station to the mobile station, the control information transmission method for the high speed downlink packet access shared channel (HS_DSCH). 2. The method of claim 1, wherein the control information is transmitted from the first base station to the second base station (HS_DSCH). 3. The method of claim 2, wherein the transmission of control information from the first base station to the second base station is performed through a control station (RNC). A wireless communication system in which a first base station transmits data to a plurality of mobile stations through one communication channel, and transmits control information for the communication channel through a control channel, wherein any one of the plurality of mobile stations is a second base station. And the second base station communicates through the control channel and the second base station does not transmit control information for the communication channel of the first base station to the mobile station. A control information transmission method for a high speed downlink packet access shared channel (HS-DSCH), characterized by increasing transmission power by a predetermined amount. 5. The fast downlink packet as claimed in claim 4, wherein when the second base station is one of active base stations targeted for handover, the increase in transmission power depends on a ratio between an active base station not transmitting control information and a total active base station. 6. Control information transmission method for the access shared channel (HS-DSCH). 5. The mobile station of claim 4, wherein when the second base station is one of active base stations targeted for handover, one of the plurality of mobile stations communicates with a third base station through the control channel, and the third base station communicates with the mobile station. High speed downlink packet access characterized in that when the control information for the communication channel of the first base station is transmitted to the third base station, the transmission power of the channel including the control information transmitted by the third base station is increased by a predetermined amount. Control information transmission method for a shared channel (HS-DSCH). 7. The method of claim 6, wherein the increase in transmission power depends on a ratio of a base station transmitting control information to a total of active base stations. 4. The method of claim 3, wherein the control station determines whether to transmit the control information and provides information to a base station.