KR100736603B1 - Method for power control of tfci field for dsch - Google Patents

Abstract

The present invention relates to a power control method for a transport format combination identifier (TFCI) field indicating a transport format of a downlink shared channel (DSCH).

Particularly, in the present invention, when a TFCI indicating a transmission format of a DSCH comes from a plurality of links, the control station allocates power in consideration of this and also allocates different power whenever the situation of a radio link changes. Is for transmitting the converted information.

According to the present invention, when TFCI for the DSCH is transmitted from a plurality of base stations when the DCH associated with the DSCH channel is soft handed over, the present invention controls power by allocating a power offset by the ratio of the number of TFCI transmission base stations to the total number of base stations. It is characterized by.

In addition, the present invention is characterized by transmitting the converted information from the control station to the base station so that different powers can be allocated when the environment of the channel or the configuration of the base station forming the radio link is changed.

Mobile communication system, power control link, downlink shared channel (DSCH)

Description

Power control method of TFCI field for downlink shared channel (DSCH). {METHOD FOR POWER CONTROL OF TFCI FIELD FOR DSCH}

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

2 illustrates a configuration of a DSCH channel

3 is a diagram illustrating a configuration of a DCH channel.

4 illustrates a field structure of DPDCH and DPCCH.

The present invention provides separate power control for a transport format combination identifier (TFCI) field indicating a transport format of a downlink shared channel (DSCH) in an IMT-2000 system (hereinafter, referred to as a 3GPP system) that promotes standardization in 3GPP. The present invention relates to a transmission power control method of a TFCI field for a downlink shared channel (DSCH) in a mobile communication system so as to improve the performance of the DSCH.                         

Particularly, in the present invention, when a TFCI indicating a transmission format of a DSCH comes from a plurality of links, the control station allocates power in consideration of this and also allocates different power whenever the situation of a radio link changes. It characterized in that for transmitting the converted information.

Figure 1 shows the structure of the UTRAN. UTRAN 20 is composed of Node B and RNC as shown in FIG. Node B is managed by the RNC and is responsible for the access point of the UTRAN, which receives information from the physical layer of the terminal (mobile station) 10 in uplink and transmits data to the terminal in 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.

2 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, multiple 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.

3 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.

There are two methods of such power control as follows.

The first method runs SSDT only on the uplink. In SSDT, during soft handover, the UE measures power from each base station, selects a base station having the largest reception power, and calls it a primary base station, and transmits the same to the base station through physical signaling.

At this time, the base stations continue to transmit when set to primary, but non-primary base stations stop transmitting. Here, operating only the uplink means that a signal for selecting a primary base station is transmitted to the uplink, but power on / off in the downlink does not operate. At this time, the DSCH power control operates in two modes.

In the case where the base station to which the DSCH is currently transmitted is a primary base station, the base station transmits the power at a predetermined level higher than the reference power, and changes the power according to the TPC command generated by the DCH.

If the base station to which the DSCH is transmitted is not the primary base station, a higher power offset is allocated. This value sets a high power offset that can be received in all areas of the cell.

The second method is a method in which a mobile station (UE) generates and transmits a TPC and a DSCH for a DCH, respectively. For this purpose, the mobile station (UE) must measure not only the DCH power but also the power of the DSCH channel. Power control of the channel is connected in conjunction with the DCH. The configuration of the DSCH channel is shown in FIG. 2, and the configuration of a downlink DCH channel is shown in FIG. 3.

Referring to FIG. 2, the DSCH channel is composed of a radio frame having a frame period T _f = 10 ms, has a structure of 15 slots (Slot # 0 to Slot # 14), and one slot T _slot = 2560. chips, consisting of N _data bits of 20 * 2 ^k bits (k = 0..6).

Referring to FIG. 3, the downlink DCH channel is composed of a radio frame having a frame period (T _f ) = 10 ms, has a structure of 15 slots (Slot # 0 to Slot # 14), and any one slot T _slot. = 2560 chips, 20 * 2 ^k bits (k = 0..7), with DPDCH (Dedicated Physical Data CHannel) and DPCCH (Dedicated Physical Control CHannel) . The first DPDCH carries N _data1 bits of data (Data1), and the next DPCCH carries TPC command N _TPC bits and TFCI N _TFCI bits, and the next DPDCH carries N _data2 bits of data (Data2). In the end, the DPCCH carries a _pilot of N _pilot bits.

Here, the TFCI bit contains information about the channel currently being transmitted. For example, information about the amount of data and the coding method transmitted in the radio frame to be transmitted is transmitted.                         

When data of a user is simultaneously transmitted through the DCH and the DSCH, the information on the DCH and the information on the DSCH should be simultaneously transmitted.

The TFCI bits transmitted per slot are divided into two, half are used for the DCH, and half are used for the DSCH.

The TFCI code word transmitted per slot is divided into two and half is used for the DCH, and half is used for the DSCH. Two methods exist for transmitting information about the DCH and the DSCH.

One of the TFCI information (TFCI1) for the DCH and the TFCI information (TFCI2) for the DSCH forms one code word by one coding (second order reed muller coding).

The other is a case where the information about the DCH and the DSCH forms a different code word through respective coding (first order reed muller coding), and the bits of the two code words are mixed and transmitted.

In the second method, even when the DCHs are transmitted by different RNCs, TFCI can be transmitted. That is, TFCI2 is transmitted from only a part of base stations in the entire Radio Link.

The TPC is a TPC for power control of the uplink channel. This is used to change the power of the uplink (reverse direction). The pilot is used to measure the power of the channel.

Meanwhile, a process of downlink (downlink) power control is performed as follows.

First, the mobile station (UE) when measuring the SIR (Signal to Interference Ratio) of DCH (estimation), and measured by comparing the measured SIR _est and the target SIR _target SIR _est is greater than the target SIR _target (SIR _est> SIR _target ) Transmits a TPC command of '0' and, if the measured SIR _est is smaller than the target SIR _target (SIR _est <SIR _target ), transmits a TPC command of '1'.

The base station then uses the transmitted TPC to adjust the power of the DCH as follows.

P (k) = P (k-1) + P _TPC (k). That is, the current power P (k) adds or subtracts the adjustment P _TPC (k) to the previous power P (k-1). When TPC _est (k) = 1, P _TPC (k) = + ΔTPC, TPC _est ( k) = 0 where P _TPC (k) = − ΔTPC. That is, when the measured SIR _est is smaller than the target SIR _target , the power of the DCH is increased by + ΔTPC, and when the measured SIR _est is larger than the target SIR _target , the power of the DCH is reduced by + ΔTPC.

Here, the TFCI field of the DPCCH has the power of P _TFCI (k) = P (k) + PO1 (where PO1 is the power offset of the DPDCH and TFCI field).

However, in the case of power control of the conventional DSCH as described above, the TFCI bit is not considered.

Since TFCI is a field belonging to the DPCCH, it undergoes the same power control as the DPCCH. However, since the TFCI can be transmitted only in some base stations, performance may be degraded.

That is, since the TFCI bit transmits important information such as the number of data bits of the currently transmitted frame, the coding method, and the like, when the TFCI is incorrectly received, the data of the radio frame cannot be detected correctly.

That is, when the TFCI bit is not properly received, since the information on the spreading factor or data amount of the DSCH is not properly transmitted, the information of the frame corresponding to the TFCI is not correctly transmitted.

On the other hand, power control during soft handover is performed with the sum of the powers transmitted from all base stations forming the active set. However, the TFCI bit for the DSCH is not transmitted at all base stations, but only at some base stations. Therefore, when power control is performed, it is difficult to adjust the power of the TFCI to maintain a constant quality.

Conventionally, the power offset of the TFCI for the DPCH can be set only during Radio Link setup. Power control such as DPCH is performed with the set power offset. That is, since the power offset of the TFCI can be changed only at the time of Radio Link setup, other power cannot be allocated when the channel environment or the configuration of the base station forming the Radio Link is changed.

In order to maintain the quality of the TFCI conventionally, a high power offset may be allocated to the TFCI field, but power is wasted because the TFCI is fixed rather than adjusted.

The present invention provides a transmission power of a transport format combination identifier (TFCI) included in a downlink dedicated channel (DCH) so that information loss is minimal even when the DCH associated with the downlink shared channel (DSCH) is in a soft handover situation. Suggest a way to control it.

According to the present invention, in performing transmission power control on the TFCI bit indicating the transmission format of the DSCH, when the TFCI comes from a plurality of links, the power offset is allocated by the ratio of the number of TFCI transmission base stations to the total number of base stations. Suggest to control.

In addition, it is proposed to transmit information on the TFCI power offset from the control station (RNC) to the base station (Node B) so that different power can be allocated whenever the situation of the radio link changes.

The present invention relates to a power control method of a TFC field for a downlink shared channel (DSCH) in a mobile communication system. The power is controlled by allocating a power offset by the ratio of the number of TFCI transmission base stations to the total number of base stations.
In addition, the present invention provides a specific base station according to a Site Selection Diversity Transmit power control (SSDT) operation for power control of a TFCI field for a downlink shared channel (DSCH) in a mobile communication system. Obtaining information on whether a primary base station is a primary base station, determining a power offset using the obtained information, and performing power control of the TFCI field according to the determined power offset.
Advantageously, said power offset is a power value added from an associated DCH.

In addition, the present invention is characterized by transmitting the converted information from the control station to the base station so as to allocate different power when the environment of the channel or the configuration of the base station forming the radio link changes.

A method of controlling transmission power of a TFCI field for a downlink shared channel (DSCH) in a mobile communication system according to the present invention will be described.

In particular, the present invention describes a power control method of the TFCI field for the DSCH channel of the 3GPP system that is effective during soft handover as an embodiment.

Typical downlink power control adjusts the power of the DPCCH and DPDCH simultaneously.

The power of each of the DPCCH and the DPDCH is adjusted by the same amount, and the relative ratio of the DPDCH and the DPCCH does not change.

However, if the DCH associated with the DSCH is in soft handover situation, a different approach is required. That is, in order to maintain the reception quality of the TFCI bit, the TFCI bit for the DSCH is subjected to different power control.

The TFCI is certainly transmitted at the base station to which the DSCH is transmitted. Transmission from other base stations can be established.

In the present invention, two methods may be considered as a power control method of the TFCI field for the DSCH channel which is effective in the handover of the 3GPP system.

One considers only the TFCI at the base station where the DSCH is transmitted, and the other considers the TFCIs transmitted at the other base station.

In the first method, it is relatively simple because it is not necessary to consider the configuration of the active set, and only the power of the TFCI transmitted from one base station is adjusted. However, more power may be allocated than necessary.                     

The other is to adjust the power of the TFCI according to the situation of the base station to which the TFCI is transmitted in the current active set. However, this method requires different settings as the configuration of the active set changes.

First, a method of considering only the TFCI field transmitted from the base station through which the DSCH is transmitted will be described. Power control of the TFCI bit for the DSCH may be applied in a manner similar to the above-described DSCH power control.

First, a method of adjusting the power of the TFCI for the DSCH according to the handover mode of the UE. That is, in the handover mode, it transmits at a constant high power, otherwise it transmits at a lower power than in the handover mode. This can be implemented by setting a new signaling TFCI power offset as the upper layer information and changing the value. When the TFCI for the DSCH is transmitted from several base stations in the active set, the power of the TFCI for the DSCH may be adjusted according to the total number of radio links and the number of links for transmitting the TFCI.

Second, a method of allocating power in a different manner depending on the mode in which the TFCI bit is selected by the UE.

3, power adjustment of DPCCH and DPDCH in the remaining portions except for the TFCI field is performed by the conventional method. However, different power control is applied to the TFCI field depending on the mode selected by the mobile station (UE).

The SSDT is operated only on the uplink, and the mobile station (UE) first measures the power coming from each base station, and sets the base station with the largest power among them as the main base station. If the base station to which the DSCH is transmitted is selected as the primary base station, power control of the TFCI field for the DSCH is performed like the other fields of the DPCCH, and if the base station to which the DSCH is transmitted is not the primary base station, the base station transmits at a constant power.

That is, the power P _TFCI (k) of the _TFCI is to _transmit P _TFCI (k) = P (k) + PO 1 + Pp when the main base station and P _TFCI (k) = Pnp when the main base station is not. Therefore, the case where the primary base station is not compared with the primary base station is transmitted with greater power.

Here, Pp is a parameter for transmitting at a higher power than the reference TFCI power, and Pnp is a parameter for constantly transmitting at a power when the mobile station UE is at the cell boundary when the base station is not the main base station.

If the SSDT mode does not operate, the base station that transmits the DSCH without transmitting power according to primay or non-primary in setting the power of the TFCI can always be set as a non-primary base station and transmitted with a constant power.

This is the same operation as the first method described above. In this case, as in the first method, the TFCI power offset, which is a new signaling for the primary / non-primary cell, may be set and the value may be changed.

P _TFCI (k) = Pnp

Alternatively, in setting the TFCI power of the base station transmitting the DSCH, power may be allocated as follows depending on whether or not the primary base station is used.

That is, the power P _TFCI (k) of _TFCI is P _TFCI (k) = P (k) + Pp when the base station transmitting the DSCH is the main base station, and P _TFCI (k when the base station transmitting the DSCH is not the main base station. ) = P (k) + Pnp.

Here, Pp is a power offset when the base station transmitting the DSCH is the main base station, and Pnp is a power offset when the base station transmitting the DSCH is not the main base station.

If the base station is not the main base station to set a high Pnp value to transmit at the power considering the cell boundary, or when setting a Pnp value above the power that can be allocated by TFCI TFCI is transmitted at full power.

When the TFCI is transmitted from several base stations, the power of the TFCI can be adjusted according to the total number of radio links and the number of base stations transmitting the TFCI for the DSCH, as in the first method.

A third method of the power control method of the TFCI field for the DSCH channel of the 3GPP system of the present invention is a case where the DSCH and the DCH are controlled by different TPCs.

That is, as a method of changing the power by a TPC different from the remaining portion except for the TFCI field for the DSCH and the TFCI field for the DSCH, the mobile station (UE) is configured for TPC1, DSCH, and TFCI for the DCH except for the TFCI field. Generate TPC2.

For this purpose, the UE measures two powers. One is for power control of the DCH, and the other is for power control of the TFCI bit for the DSCH and the DSCH. SIR is measured using a pilot of the DPCCH to make a TPC for the DCH.

On the other hand, the TFCI bit and the DSCH channel are used for the DSCH channel. When using the DSCH channel, it is easy to measure SIR because it is transmitted continuously with strong power.

However, there is a frame in which the DSCH is not transmitted. This prevents SIR measurements in this section.

The TFCI bit occupies only a portion in one slot but is transmitted continuously, so the SIR can be measured in every frame. DCH excluding the TFCI bit is adjusted in power like P1, and the DSCH and TFCI bits are adjusted in P2.

That is, P1 (k) = P1 (k-1) + P _TPC1 (k). That is, the power P1 (k) of the DCH present except the TFCI bits for subtraction to jojeongbun P _TPC1 (k) by the TPC1 to the previous power P1 (k-1), TPC1 est (k) = 1 when P _TPC1 (k ) = + ΔTPC, P _TPC1 (k) = -ΔTPC when TPC1 _est (k) = 0. That is, if the measured SIR _est is smaller than the target SIR _target , the power of DCH excluding TFCI is increased by + ΔTPC. If the measured SIR _est is larger than the target SIR _target , the power of DCH excluding TFCI is reduced by + ΔTPC. It is to let.

On the other hand, P2 (k) = P2 (k-1) + P _TPC2 (k). That is, the current P2 (k) of the DSCH and TFCI bits is added to or subtracted the adjustment P _TPC2 (k) by TPC2 to the previous power P2 (k-1), which is P _TPC2 (k) when TPC2 _est (k) = 1. P _TPC2 (k) = -ΔTPC when TPC2 _est (k) = 0. That is, when the measured SIR _est is smaller than the target SIR _target , the power of the DSCH and TFCI bits is increased by + ΔTPC. When the measured SIR _est is larger than the target SIR _target , the power of the DSCH and TFCI is reduced by + ΔTPC. will be.

Where P _TFCI (k) = P2 (k) + PO1 (where PO1 is the power offset of the DPDCH and TFCI fields).

On the other hand, the power of the TFCI can be adjusted by a separate control signal in addition to the TPC. If the DSCH channel power is controlled by a report on measuring a signal to interference ratio (SIR) or by a report on a cyclic redundancy check (CRC) check, TFCI power control can be performed in conjunction with this.

In addition, in the case of a base station transmitting a DSCH, both the first method and the second method of the present invention can be applied to both the user at the time of handover or otherwise.

That is, in the power control of the TFCI field for the base station transmitting the DSCH, power of a different method depending on the mode in which the user (mobile station) selects the TFCI bit regardless of whether the user (mobile station) is in handover or not. Can be used, and a method of allowing the DSCH and the DCH to be controlled by different TPCs can be used.

In addition, in allocating power of TFCI bits for DSCH, a method of allocating power such as TFCI for DCH and a method of allocating different power may be used. That is, the power of the TFCI bit for the DSCH is allocated to the same power as the TFCI for the DCH or different powers are allocated.

The DCH is transmitted in a QPSK signal.

On the other hand, when power control of the TFCI bit for the DSCH and the TFCI for the DCH differently, a real signal and an imaginary signal of one symbol may have different powers. That is, this case occurs when two bits are allocated as the TFCI field as shown in FIG. To prevent this, adjust the entire TFCI field to the power of P2.

That is, the TFCI bit includes the TFCI bit for the DCH and the TFCI bit for the DSCH, and the bit for the DCH and the DSCH is transmitted in one symbol. In this case, the TFCI field including the TFCI bits is used as the TFCI for the DSCH. Power control is performed according to the TPC for power control of bits.

The power offset varies depending on whether it is primary or non-primary. As in the case where only one base station is considered, power offsets of the primary base station and the non-primary base station may be allocated together. That is, a power offset is allocated according to the number of transmitting base stations with respect to the total number of base stations according to whether or not the soft handover state is present.

As described above, suppose that a UE is in handover mode and receives channel A transmitted from several base stations and channel B transmitted only from one base station. In this case, when information related to channel B is transmitted only from some base stations of the active set through channel A, the field containing the information performs power control different from that of other parts of channel A. After the information is transmitted to the base station belonging to the channel B, power control is performed in accordance with the channel B. At this time, it is possible to maintain power for the quality of information whether or not information is transmitted from other base stations. And it is possible to prevent the waste of power by not transmitting from other base stations.

Considering the case of transmitting from some base stations, when considering the transmission from several base stations through channel A, power control is performed by assigning each power offset to each base station.

In order to operate in the 3GPP system of the present invention, information on the TFCI power offset should be transmitted from the RNC to Node B. In the case of the first method, one power offset should be set. In the second method, two power offsets should be set. In addition, information transmission from the RNC to the Node B is required depending on the radio link situation.

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.

The present invention proposes a power control scheme of TFCI, which can reduce signal loss even when the DCH associated with the DSCH is in a soft handover situation. The power quality of the TFCI bit for the DSCH can be improved by performing power control separate from the DCH. If the TFCI bit is not properly received, since information on the spreading factor or data amount of the DSCH is not properly transmitted, information of the frame corresponding to the TFCI is not correctly transmitted. However, according to the present invention, since such a concern can be solved, the performance of the DSCH can be improved.

In addition, when the power control of the conventional DSCH channel using a separate TPC, there is a disadvantage that the TPC cannot be generated because the SIR of the DSCH cannot be measured when the DSCH is not delivered. However, in the present invention, power control of the TFCI bit according to the TPC for power control of the DSCH may generate the TPC by receiving the power of the TFCI even when the DSCH channel is not transmitted.

Claims (7)

In the power control method of the TFCI (Transport Format Combination Indicator) field for the downlink shared channel (DSCH) in a mobile communication system, Acquiring information about whether a specific base station is a primary base station according to a Site Selection Diversity Transmit power control (SSDT) operation; Determining a power offset using the obtained information; And Performing power control of the TFCI field according to the determined power offset Power control method of the TFCI field for a downlink shared channel (DSCH) comprising a. The method of claim 1, The power offset is a power offset for a dedicated channel (DCH) associated with the shared channel (DSCH). Power control method of the TFCI field for the downlink shared channel (DSCH), characterized in that. The method of claim 1, The DCH includes a Dedicated Physical Data Channel (DPDCH) and a Dedicated Physical Control Channel (DPCCH). Power control method of the TFCI field for the downlink shared channel (DSCH), characterized in that. The method of claim 1, The power offset changes over time Power control method of the TFCI field for the downlink shared channel (DSCH), characterized in that. The method of claim 1, The TFCI field is a codeword generated by a specific first coding method, The TFCI field for the DCH is a codeword generated by a specific second coding method. Power control method of the TFCI field for the downlink shared channel (DSCH), characterized in that. The method of claim 1, The power offset is, If the base station transmitting the TFCI field is not the main base station compared to the case of the main base station, it is determined larger Power control method of the TFCI field for the downlink shared channel (DSCH), characterized in that. In the power control method of the TFCI (Transport Format Combination Indicator) field for the downlink shared channel (DSCH) in a mobile communication system, Measuring a first signal to interference ratio (SIR) value by using a pilot signal of a dedicated physical data channel (DPDCH); Measuring a second SIR value using the TFCI field included in a DPCCH; Independently performing power control of a dedicated channel (DCH) associated with the DSCH and power control of the TFCI field using the first SIR value and the second SIR value. Power control method of the TFCI field for a downlink shared channel (DSCH) comprising a.

Images