CN100442935C - A high-speed downlink packet access handover method - Google Patents

Abstract

The present invention provides a high-speed downlink packet access switching method, wherein, during the high-speed downlink packet access (HSDPA) switching process in the base station, all uplink high-speed dedicated physical control channel (HS-DPCCH) signals in the switching area are Maximum ratio combining, and performing data reception acknowledgment (ACK/NACK) judgment and channel quality indicator (CQI) decoding on the combined signal. In order to improve the demodulation gain of the uplink HS-DPCCH channel, increase the reliability of ACK/NACK decision and CQI information decoding after demodulation.

Description

A high-speed downlink packet access handover method

technical field

The invention relates to wireless communication technology, in particular to high-speed downlink packet access (HSDPA) technology in wideband code division multiple access (WCDMA) technology, specifically a high-speed downlink packet access switching method.

Background technique

The full name of HSDPA is High Speed Downlink Packet Access (High Speed Downlink Packet Access), which is an important feature of the fifth version of WCDMA technology. A series of key technologies realize downlink high-speed data transmission.

In the WCDMA system, the introduction of HSDPA adds three channels, namely, the high-speed physical downlink shared channel (HS-PDSCH) for transmitting data information in the downlink, and the high-speed shared control channel (HS-SCCH) for transmitting downlink control information. And a high-speed dedicated physical control channel (HS-DPCCH) for transmitting uplink feedback information.

Compared with the dedicated channel (DCH), HSDPA has great advantages. Mainly in:

1) Multiple users in the cell share all resources of HSDPA. A cell can use up to 15 HS-PDSCH channels, and the spreading factor of the channel code used by each channel is fixed at 16. These data-carrying channels can be reasonably and dynamically allocated to each user according to the user's data transmission requirements and the channel environment. At the same time, resources can also be allocated to multiple users according to a certain ratio (as shown in Figure 1) . By using a certain scheduling algorithm, the system can also allocate more HS-PDSCH channels to users with good channel environment, so that the capacity of the system can be further improved. For dedicated channels, the system must allocate fixed resources for each user. When a certain user does not transmit data, the resources allocated to this user cannot be used by other users, resulting in waste of resources. Therefore, HSDPA technology is very suitable for those non-real-time services whose data transmission requirements are sudden, and the data transmission delay is not as high as conversational services such as voice calls.

The fast scheduling algorithm is to enable multiple users to use wireless resources more effectively and improve the throughput of the entire sector in a dynamic and complex wireless environment. The scheduling algorithm function is implemented in the base station, using the technology of time division plus code division, and the user's right to use the shared channel can be rescheduled for every 2ms wireless subframe, greatly improving the response speed.

2) The adaptive modulation and coding function of HSDPA enables the 16QAM modulation method to be used when the user's channel environment is relatively good, and a high coding rate is used, so that the same signal code and power resources are used. , high-speed data transmission is obtained, and the resource utilization rate of channel code and power is increased by 100% or even more than that of the DCH channel. If a cell is configured with 15 HS-PDSDCH channels, theoretically the maximum data transmission rate of each user can reach 13.976Mbps when the channel environment of the user allows. Therefore, HSDPA is a solution for WCDMA downlink high-speed data access, which can effectively solve the problem of limited downlink capacity.

3) In addition, HSDPA uses hybrid retransmission (HARQ) technology to directly retransmit data that fails to be transmitted at the physical layer. Compared with the retransmission of the high-level protocol RLC layer of the DCH channel, it greatly reduces the time caused by data retransmission. Delay, thus providing users with a higher quality of service.

Figure 2 is a schematic diagram of a user using HSDPA for data transmission in a WCDMA system.

In the air interface part of Figure 2, for each user using HSDPA for data transmission, a bidirectional DCH signaling channel, an uplink HS-DPCCH channel, a downlink HS-PDSCH channel, and an uplink must be established at the same time DCH traffic channel.

Among them, the bidirectional DCH signaling channel is used to transmit signaling messages interacted between the user and the network, such as handover commands, service establishment messages, and measurement control, etc., the downlink HS-PDSCH channel is used to transmit downlink service data, and the uplink The DCH service channel is used to transmit uplink service data or status reports corresponding to downlink service data.

In particular, the uplink HS-DPCCH channel is used by the user to feed back the acknowledgment information of data reception (ACK if the data is received correctly, NACK if the data reception fails) and channel quality indication (CQI) to the base station. If the user feeds back NACK, it means that the data block sent from the HS-PDSCH channel at the previous moment was not correctly received by the user, so the base station will send the data that was not correctly received by the user again at the next sending time until the user receives it correctly And feedback ACK. In the implementation of the HSDPA algorithm, the user equipment (UE) feeds back the channel quality indicator CQI of the downlink HS-PDSCH channel in the uplink HS-DPCCH, and through the analysis of the CQI reported by all UEs, the base station (NodeB) can obtain the channel of each UE Quality conditions, so as to determine the allocation of shared resources in each UE.

The transmission of HS-PDSCH and HS-SCCH of the same user is only allocated to one bearer in the wireless link of the user terminal, that is, the serving cell. That is to say, HSDPA only supports hard handover, not soft handover or softer handover. There is only one downlink HS-PDSCH and one HS-SCCH in the handover area, and there is only one uplink HS-DPCCH sent by the UE, but in fact the NodeB can receive the uplink HS-DPCCH signal sent by the UE in both cells. Hard handover often has only one link in the handover area. Generally, the reception of HS-DPCCH channels also adopts hard handover, that is, only the uplink HS-DPCCH channel of one cell is received during the handover process. According to the ACK/NACK on the demodulated channel Information to carry out HSDPA HARQ control, according to the CQI information demodulation of this channel to carry out adaptive modulation and coding control of HSDPA.

HSDPA handover process in the base station: First, there is an HSDPA channel (including HS-PDSCH, HS-SCCH and HS-DPCCH) in the serving cell. When the UE enters the target cell from the serving cell, the NodeB will establish a channel in the target cell. R99 channel (non-HSDPA channel), the UE will report the quality of the primary common pilot channel (P-CPICH) of the serving cell and the target cell to the radio network control (RNC), and the RNC finds that the quality of the P-CPICH of the target cell is greater than that of the serving cell. -CPICH quality, then change the serving cell (that is, the target cell becomes the serving cell, and the original serving cell becomes the target cell), the RNC stops the signal transmission of the original serving cell to the user through a synchronous reconfiguration message, and establishes a new one on the target cell Transmission channel, the NodeB will send the downlink HSDPA channel according to the new serving cell parameters, and at the same time, the RNC requires the UE to replace the target cell with the serving cell, and requires the UE to receive the downlink HSDPA channel according to the new serving cell parameters, and send the uplink HSDPA channel according to the new serving cell parameters. HS-DPCCH channel, and the NodeB receives the HS-DPCCH channel sent by the UE according to the new serving cell parameters.

Fig. 3 is the frame structure of uplink HS-DPCCH channel, and it has shown a 10ms radio frame, and this radio frame is made up of a plurality of subframes, and in a 2ms HS-DPCCH subframe wherein, a timeslot (T _slot = 2560 chips) are used for hybrid automatic repeat request acknowledgment (HARQ-ACK), and the other two time slots (2×T _slot =5120 chips) are used for channel quality indication (CQI).

In the prior art, the base station only receives the uplink HS-DPCCH channel of one cell during the HSDPA handover process. The disadvantage is that the signals of the uplink HS-DPCCH channel of all cells in the handover area are not fully utilized, and there is a certain performance loss, which reduces the reliability of the ACK/NACK judgment of the uplink HS-DPCCH channel and the decoding of CQI information.

Contents of the invention

The purpose of the present invention is to provide a high-speed downlink packet access switching method to improve the uplink HS-DPCCH channel demodulation gain and increase the reliability of ACK/NACK decision and CQI information decoding after demodulation.

The technical solution of the present invention is: a high-speed downlink packet access switching method, wherein, during the high-speed downlink packet access (HSDPA) switching process in the base station, an uplink high-speed dedicated physical control channel is established in the target cell, and the target cell and the service The uplink high-speed dedicated physical control channel (HS-DPCCH) signal of the cell is combined by maximum ratio.

Judgment of data reception acknowledgment information (ACK/NACK) and decoding of channel quality indication (CQI) are performed on the combined signal.

The high-speed downlink packet access (HSDPA) switching process in the base station includes the following steps: establishing an uplink high-speed dedicated physical control channel (HS-DPCCH) on the target cell, and making the uplink high-speed dedicated physical control channel (HS-DPCCH) ) is consistent with the channel parameters of the uplink high-speed dedicated physical control channel (HS-DPCCH) of the serving cell; channel demodulation is performed on the uplink high-speed dedicated physical control channel (HS-DPCCH) of the serving cell; the uplink of the target cell Perform channel demodulation on the high-speed dedicated physical control channel (HS-DPCCH); combine the channel demodulation results of the uplink high-speed dedicated physical control channel of the serving cell with the channel demodulation results of the target cell's uplink high-speed dedicated physical control channel to obtain a combined Post-signal: Judgment of data reception acknowledgment information and decoding of channel quality indication are performed on the post-combination signal.

When the channel parameters of the uplink high-speed dedicated physical control channel change: all the channel parameters of all uplink high-speed dedicated physical control channels (HS-DPCCH) under the same user are replaced with new channel parameters; according to the new The channel parameters perform channel demodulation on each uplink high-speed dedicated physical control channel; combine the channel demodulation results of each uplink high-speed dedicated physical control channel with a maximum ratio to obtain a combined signal; perform data reception confirmation information on the combined signal decision and decoding of the channel quality indication.

The maximum ratio combination refers to weighted addition according to the received signal quality of each uplink high-speed dedicated physical control channel to be combined.

The data reception confirmation information refers to: ACK information when data is received correctly or NACK information when data reception fails.

The beneficial effect of the present invention is that, by providing a high-speed downlink packet access switching method, in the HSDPA switching process, the maximum ratio combining method is adopted for all uplink HS-DPCCH channels in the switching area, which can improve the uplink HS-DPCCH channel Demodulation gain, which increases the reliability of ACK/NACK decision and CQI information decoding after demodulation.

Description of drawings

FIG. 1 is a schematic diagram of HSDPA resource scheduling among multiple users in the prior art;

Fig. 2 is the structural block diagram that the user utilizes HSDPA to carry out data transmission in the prior art;

Figure 3 is a frame structure diagram of the uplink HS-DPCCH;

Fig. 4 is the flowchart of activating HSDPA on the R99 channel basis of the present invention;

Fig. 5 is a flow chart of the uplink demodulation of the base station when the cell is changed according to the present invention.

Detailed ways

The specific embodiment of the present invention is described below in conjunction with accompanying drawing, and the purpose of the present invention mainly is to propose in the HSDPA switching process in the base station, utilize the signal of the uplink HS-DPCCH channel of all sub-districts, carry out all uplink HS-CPCCH signals in the handover area The maximum ratio combination improves the demodulation gain of the uplink HS-DPCCH channel, and increases the reliability of the demodulated ACK/NACK decision and CQI information decoding.

As shown in Figure 4, during the HSDPA handover process in the base station, when an R99 channel is established in the target cell, the base station (NodeB) informs the uplink demodulation processing module of the newly added R99 channel and the HS-DPCCH channel of the serving cell through internal signaling Belonging to the same user, and must perform softer combination, when the uplink demodulation processing module establishes a new R99 channel internally, it will automatically activate HSDPA on the basis of the R99 channel, that is, establish an uplink HS-DPCCH channel on the target cell. The HS-DPCCH channel parameters are consistent with the HS-DPCCH channel parameters of the serving cell, and the ACK/NACK judgment and CQI decoding are not performed immediately after the HS-DPCCH channel demodulation of the serving cell, but wait until the HS-DPCCH channel of the target cell After the channel demodulation is completed, the demodulation results of the two channels are combined at the maximum ratio (the maximum ratio combination is a weighted addition based on the quality of the signals received by the channels to be combined, that is, the channel with good quality has a larger weight, and the channel with poor quality The channel weight is small, and then each demodulated symbol on the corresponding channel is multiplied by the weight, and the symbols corresponding to the last two channels are added), and the combined signal is then subjected to ACK/NACK judgment and CQI decoding . The weight is related to the quality of the signal, that is, the square of the amplitude of the received signal.

As shown in Figure 5, if the radio network control (RNC) requires the serving cell to be changed through a synchronous reconfiguration message, that is, to change the uplink HS-DPCCH channel parameters, the NodeB uplink demodulation module should transfer all HS-DPCCH channel parameters under the same user The parameters are all replaced with the latest parameters. Then carry out the demodulation of each HS-DPCCH channel according to the latest parameters, and carry out the maximum ratio combination of each HS-DPCCH channel (the maximum ratio combination is to carry out weighted addition according to the signal quality received by the channel to be combined, that is, the channel weight of good quality The weight of the channel with large and poor quality is small, and then multiply each demodulated symbol on the corresponding channel with the weight, and add the symbols corresponding to the last two channels), and finally perform ACK/ NACK decision and decoding of CQI.

The latest parameters include ACK/NACK repetition factor, ACK/NACK repetition period, CQI repetition factor, and CQI repetition period. Among them, the ACK/NACK repetition period refers to the frequency of reporting ACK/NACK each time, and the value range is 2ms, 4ms, 8ms, 10ms, 20ms, 40ms, 80ms and 160ms. For example, ACK/NACK is reported every 160ms; repetition factor Refers to the number of repeated reports within this period, and the value range is 1 to 4. ACK/NACK reports a different value every 160ms, and reports the same value 4 times within 160ms to increase the reporting gain. CQI is also similar.

During the HSDPA handover process, the maximum ratio combination method is used for all uplink HS-DPCCH channels in the handover area, which can improve the demodulation gain of the uplink HS-DPCCH channel, increase the efficiency of ACK/NACK judgment after demodulation and CQI information decoding reliability.

The above specific embodiments are only used to illustrate the present invention, but not to limit the present invention.

Claims (6)

1. high-speed down packet cut-in switching method, it is characterized in that, high speed downlink packet inserts in the handoff procedure in the base station, set up uplink high-speed special physical control channel at Target cell, the uplink high-speed special physical control channel signal of Target cell and Serving cell is carried out high specific merge.

2. method according to claim 1 is characterized in that, carries out the judgement of data reception acknowledgement information and the decoding of channel quality indication for the signal after merging through high specific.

3. method according to claim 1, it is characterized in that, describedly set up uplink high-speed special physical control channel, the uplink high-speed special physical control channel signal of Target cell and Serving cell carried out high specific merge and may further comprise the steps at Target cell:

On Target cell, set up uplink high-speed special physical control channel, and make the channel parameter of this uplink high-speed special physical control channel consistent with the channel parameter of the uplink high-speed special physical control channel of Serving cell;

Uplink high-speed special physical control channel to Serving cell carries out channel demodulation;

Uplink high-speed special physical control channel to Target cell carries out channel demodulation;

The channel demodulation result of Serving cell uplink high-speed special physical control channel and the channel demodulation result of Target cell uplink high-speed special physical control channel are carried out the high specific merging, obtain combined signal;

Described combined signal is carried out the judgement of data reception acknowledgement information and the decoding of channel quality indication.

4. method according to claim 1 is characterized in that, when the channel parameter of described uplink high-speed special physical control channel changes:

The channel parameter of all uplink high-speed special physical control channels under the same user is all replaced with new channel parameter;

According to described new channel parameter each uplink high-speed special physical control channel is carried out channel demodulation;

The channel demodulation result of each uplink high-speed special physical control channel is carried out the high specific merging, obtain combined signal;

Described combined signal is carried out the judgement of data reception acknowledgement information and the decoding of channel quality indication.

5. according to any described method of claim 1 to 4, it is characterized in that described high specific merging is meant: the signal quality that each uplink high-speed special physical control channel that merges according to need receives is weighted addition.

6. according to any described method of claim 2 to 4, it is characterized in that described data reception acknowledgement information is meant: the nack message when ACK information when data correctly receive or Data Receiving failure.

Images