CN101242566A - Multimedia broadcast multicast service transmission method, system and base station - Google Patents

Abstract

The present invention provides a mode of transmission of MBMS, including: UE measuring self-CQI, sending CQI back to the base station when the CQI satisfies the feedback conditions, the base station determining the present worst CQI according to CQI sent by UE, transmitting MBMS data according to worst CQI. The invention makes the base station transmit MBMS data according to the present channel condition, improving the utilization rate of channel resources, and reducing signaling interactive; further, the invention adopts identical modulation type, different code rate MCS for the same region by dividing the base station, each base station adjusts the code rate according to the present worst CQI at the same time, the base stations belonging to the same region adopts coded block transmitted by the base station having the lower code rate and the coded block transmitted by the base station having the higher code, which can improve the utilization rate of channel resources, and enhance the macro diversity gain of MBMS at the same time when transmitting the same MBMS data.

Description

Multimedia broadcast multicast service transmission method, system and base station

technical field

The invention relates to the technical field of service transmission, in particular to a multimedia broadcast multicast service transmission method, system and base station.

Background technique

With the development of mobile communication systems, more and more attractive services emerge, such as Multimedia Broadcast Multicast Service (MBMS). In the current 3rd Generation Partnership Project (3GPP) standard, MBMS data is transmitted to user equipment (UE) in point-to-point (PTP) or point-to-multipoint (PTM) mode. At the same time, in the 3GPP standard, the transmission efficiency of MBMS data is improved by switching between PTP and PTM modes. When the number of users is small, the PTP mode is adopted, and when the number of users is large, the PTM mode is adopted.

In PTP mode, each user can feed back its own channel quality indicator (CQI). According to the CQI and MBMS quality of service (QoS) requirements, only the base station with the best channel conditions can be selected as the user's serving base station. In the PTM mode, the uplink feedback mechanism is not supported, and the base station needs to support the edge coverage capability with a data rate of 64Kbps-256Kbps.

The existing method for transmitting MBMS data has the following disadvantages: one, because the PTM mode does not support the uplink feedback mechanism, the base station cannot know the user's CQI, therefore, the base station cannot adjust the modulation and coding scheme (MCS) of MBMS, so the user cannot obtain The macro-diversity gain reduces the quality of MBMS data transmission and wastes channel resources. At the same time, not all MBMSs need to support edge coverage, which leads to a decrease in system efficiency. 2. In PTP mode, since each user occupies a dedicated channel, if the base station wants to send the same downlink signal to multiple users at the same time, it also needs to occupy downlink channels equal to the number of users, which will also cause a waste of channel resources . In addition, switching between PTP and PTM modes only according to the number of users without considering actual channel conditions may also cause waste of channel resources.

Contents of the invention

The invention provides an MBMS transmission method, system and base station to improve the utilization rate of channel resources.

The technical scheme provided by the invention is as follows:

An MBMS transmission method, comprising:

The user equipment (UE) measures its own CQI, and feeds back the CQI to the base station when its own CQI meets the feedback conditions. The base station determines the current worst CQI according to the CQI fed back by the UE, and uses the current worst CQI to transmit MBMS data.

After the UE measures its own CQI, it further includes: when the UE determines that the statistical condition is satisfied, it performs statistics on the measured CQI, and judges whether the statistically obtained CQI meets the feedback condition, and if so, determines that its own CQI meets the feedback condition.

The base station determining the current worst CQI includes: the base station judges whether the CQI fed back by the UE is lower than its own current worst CQI, and if so, updates the current worst CQI with the CQI fed back by the UE;

Or, the base station judges whether the ratio of the number of the worst CQIs lower than its own to the number of all the CQIs received among all the received CQIs satisfies the preset ratio, and if so, the base station that satisfies the preset ratio is lower than The minimum value among the CQIs of the current worst CQI updates the current worst CQI.

After the base station determines the current worst CQI, it further includes: the base station broadcasts the current worst CQI.

The CQI satisfying the feedback condition is: the CQI is lower than the current worst CQI received by the UE from the base station last time, or the difference between the CQI and the current worst CQI received by the UE last time from the base station is within a preset within the specified range.

The UE feeds back the CQI to the base station as follows: when the UE is in the connected state, the UE feeds back the CQI to the base station through the pre-allocated uplink dedicated channel (DCH); when the UE is in the idle state, the UE uses the pre-allocated uplink random access The channel (RACH) feeds back the CQI to the base station;

Before the base station determines the current worst CQI, it further includes: the base station receives all CQIs fed back through the uplink DCH.

The method further includes: the base station does not receive any CQI fed back by the UE within a predetermined number of consecutive frames, and increases the value of the current worst CQI according to a preset adjustment step.

After the base station increases the value of the current worst CQI, it further includes: the base station broadcasts the increased current worst CQI value, and judges whether the CQI fed back by the UE is received within a predetermined period of time, and if so, readjusts according to the CQI fed back by the UE The current worst CQI; otherwise, keep the added current worst CQI unchanged.

The base station determining the current worst CQI includes:

A. The base station judges whether the difference between the CQI fed back by the UE and the current worst CQI is within the preset positive number range. If it is, put the CQI into the first preset array and execute step B; if not, Judging whether the difference between the CQI and the current worst CQI is within the preset negative range, if so, putting the CQI into the preset second array, and performing step B, otherwise, directly performing step B;

B. The base station detects that the preset current worst CQI adjustment condition is satisfied, adjusts the current worst CQI according to the CQIs in the first array and the second array, and takes the adjusted CQI as the current worst CQI.

The base station adjusting the current worst CQI in step B includes: the base station judges whether the second array contains CQI, and if so, reduces the value of the current worst CQI according to the worst CQI in the second array; otherwise, according to the value of the worst CQI in the first array The worst CQI of , increase the value of the current worst CQI.

The base station adjusting the worst CQI in step B includes: the base station judges whether the ratio of the number of CQIs saved in the first array to the number of CQIs saved in the second array is greater than the first preset value, and if so, increases the current worst CQI Otherwise, determine whether the ratio of the number of CQIs stored in the first array to the number of CQIs stored in the second array is less than the second preset value, and if so, reduce the value of the current worst CQI.

The method further includes: dividing all base stations into more than one area in advance, and setting base stations belonging to the same area to use the same modulation method at the same time;

The base station transmitting MBMS data according to the current worst CQI includes: the base station encodes the MBMS data, determines the code rate of the current modulation mode according to the current worst CQI, and transmits the code block corresponding to the low code rate according to the determined code rate Compatible with the principle of transmitting coded blocks corresponding to high code rates, select the coded blocks for transmission, and send the selected coded blocks to the UE.

The method further includes: dividing all base stations into more than one area in advance, and setting base stations belonging to the same area to use the same modulation method at the same time;

The transmission of MBMS data by the base station according to the current worst CQI includes: the base station encodes the current MBMS data, and sends the current worst CQI to the MBMS Radio Access Network (RAN) controller, and the MBMS RAN controller uses the current worst CQI Determine the code rate of the current modulation mode and send the code rate to the base station. The base station selects the code block for transmission according to the code rate and the principle that the transmission code block corresponding to the low code rate is compatible with the transmission code block corresponding to the high code rate. The selected coded block is sent to the UE.

After the base station determines the current worst CQI, it further includes: the base station adjusts its own current worst CQI according to the current worst CQI sent by the neighboring base station using the same modulation mode as itself, and sends the adjusted current worst CQI of itself sent to its neighboring base stations.

An MBMS transmission system, comprising: a UE and a base station, wherein:

The UE measures its own CQI, and feeds back the CQI to the base station when its own CQI meets the feedback condition;

The base station receives the CQI fed back by the UE, determines the current worst CQI according to the CQI, and transmits MBMS data according to the worst CQI.

The system further includes: a RAN controller, configured to divide all base stations into more than one area, assign the same modulation mode to base stations in each area, and send the modulation mode to each base station;

The base station further selects the code rate of the current modulation scheme according to the current worst CQI, and selects the transmission code block from the MBMS data code blocks according to the principle that the transmission code block corresponding to the low code rate includes the transmission code block corresponding to the high code rate.

The RAN controller divides all base stations into more than one area, assigns the same modulation mode to the base stations in each area, receives the current worst CQI sent by the base station, and selects a code rate for the base station according to the current worst CQI, and uses the code The rate is sent to the base station;

The base station further sends the current worst CQI to the RAN controller, receives the code rate sent by the RAN controller, and according to the code rate and the principle that the transmission coding block corresponding to the low code rate is compatible with the transmission coding block corresponding to the high code rate, Select the transport coding block among the MBMS data coding blocks.

A base station for MBMS transmission, comprising: a worst CQI determination module and an MBMS transmission module, wherein:

The worst CQI determination module receives the CQI fed back by the UE, determines the current worst CQI according to the CQI, and sends the current worst CQI to the MBMS transmission module;

The MBMS transmission module receives the current worst CQI sent by the worst CQI determination module, and transmits MBMS data according to the CQI.

The worst CQI determination module further broadcasts its current worst CQI.

The worst CQI determination module further increases the value of the current worst CQI according to a preset adjustment step size if no UE feedback CQI is received within a predetermined number of consecutive frames.

The worst CQI determination module further broadcasts the increased current worst CQI value, and judges whether the CQI fed back by the UE is received within a predetermined time period, and if so, readjusts the current worst CQI according to the CQI fed back by the UE; otherwise, The current worst CQI after the increase is kept unchanged.

The worst CQI determination module further receives the CQI fed back by the UE, and judges whether the difference between the CQI and the current worst CQI is within a preset positive number range, and if so, puts the CQI into the preset first array Otherwise, determine whether the difference between the CQI and the current worst CQI is within the preset negative range, if so, put the CQI into the second preset array; detect that the current worst CQI adjustment that meets the preset The condition is to adjust the current worst CQI according to the CQIs in the first array and the second array.

The MBMS transmission module further determines the code rate of the current modulation mode according to the current worst CQI sent by the worst CQI determination module, and according to the code rate, the transmission coding block corresponding to the low code rate is compatible with the transmission coding corresponding to the high code rate The principle of the block, selects the transmission coding block in the MBMS data coding block.

The worst CQI determination module further receives the current worst CQI sent by the neighboring base station using the same modulation mode as itself, adjusts its own current worst CQI according to the CQI, and sends the adjusted current worst CQI to the its own neighboring base stations.

Compared with the prior art, the present invention feeds back the CQI to the base station when the UE's own CQI meets the feedback conditions, and the base station determines the current worst CQI according to the CQI fed back by the UE, and transmits MBMS data according to the current worst CQI. It enables the base station to transmit MBMS data according to the current channel conditions, improves the utilization rate of channel resources, and reduces signaling interaction; further, the present invention divides the base stations into areas, adopts the same modulation method for the base stations in the same area, and at the same time Adjust the code rate for each base station according to the current worst CQI. For base stations belonging to the same area, when transmitting the same MBMS data, the coded blocks transmitted by the base station with a low code rate are compatible with the coded blocks transmitted by a base station with a high code rate. This makes it possible to improve the macro-diversity gain of MBMS while improving the utilization rate of channel resources.

Description of drawings

FIG. 1 is a flow chart of transmitting MBMS data provided by Embodiment 1 of the present invention;

FIG. 2 is a schematic diagram of an example of applying Embodiment 1 of the present invention;

FIG. 3 is a flow chart of transmitting MBMS data provided by Embodiment 2 of the present invention;

FIG. 4 is a schematic diagram of an example of applying Embodiment 2 of the present invention;

FIG. 5 is a flow chart of transmitting MBMS data provided by Embodiment 3 of the present invention;

FIG. 6 is a flow chart of transmitting MBMS data provided by Embodiment 4 of the present invention;

FIG. 7 is a flow chart of transmitting MBMS data provided by Embodiment 5 of the present invention;

FIG. 8 is a flow chart of transmitting MBMS data provided by Embodiment 6 of the present invention;

Fig. 9 is a schematic diagram of an example of applying Embodiment 6 of the present invention;

FIG. 10 is a system composition diagram for transmitting MBMS data provided by an embodiment of the present invention;

FIG. 11 is a schematic structural diagram of a base station for transmitting MBMS data provided by an embodiment of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Embodiment one:

Fig. 1 is the flow chart of transmitting MBMS data provided by Embodiment 1 of the present invention, as shown in Fig. 1, its specific steps are as follows:

Step 101: Pre-allocate one or more uplink DCHs and one or more uplink RACHs for the UE. The uplink DCHs are used to carry the CQI fed back by the UEs in the RRC connected state, and the uplink RACHs are used to carry the feedbacks from the UEs in the RRC idle state. The CQI. At the same time, the UE in the RRC connected state feeds back the CQI, the UE in the RRC idle state feeds back the CQI, sends the current worst CQI, and assigns time slots for sending MBMS data.

Among them, the time slot allocated for the UE in the connected state to feed back the CQI should be located before the time slot allocated for delivering the current worst CQI, and the time slot allocated for delivering the current worst CQI should be located in the time slot allocated for delivering MBMS data. before the time slot. The time slot allocated for the UE in the idle state to feed back the CQI only needs to be before the time slot allocated for delivering the current worst CQI.

Step 102: UE measures its own CQI.

Step 103: The UE judges whether the CQI measured by itself satisfies the feedback condition, and if so, executes Step 104; otherwise, the process ends.

In this step, the UE may judge whether the CQI satisfies the feedback condition every time it measures the CQI, and if so, feed back the CQI. CQI statistics, such as: calculating the average value or weighted average value of each CQI to obtain the statistical value of the CQI, judging whether the obtained statistical value of the CQI meets the feedback condition, and if so, feeding back the statistical value of the CQI.

The feedback condition may be: the CQI measured by the UE is lower than the worst CQI heard by the UE on the MBMS indicator channel (MICH) last time; The CQI difference falls within a predetermined range, for example: the CQI measured by the UE falls within mdB or within n data levels of the worst CQI heard by the UE last time on the MICH, where m and n are determined by the base station It is determined based on experience and then sent to the UE, or determined by the base station according to the current number of users and then sent to the UE.

Step 104: The UE selects a channel and time slot for feeding back the CQI according to its own state, and feeds back the CQI to the base station.

Step 105: The base station receives the CQI sent by the UE, and judges whether the current worst CQI adjustment condition is met, and if so, executes step 106; otherwise, goes to step 108.

Step 106: The base station updates the current worst CQI stored by itself according to the CQI fed back by the UE.

The worst CQI adjustment condition can be that the CQI fed back by the UE is lower than the current worst CQI saved by the base station itself, and at this time, the current worst CQI is updated with the CQI fed back by the UE; When the ratio of the worst CQI to the total number of CQIs fed back by the UE satisfies a predetermined ratio, update the current worst CQI with the minimum value of the CQIs that meet the predetermined ratio and are lower than the current worst CQI, for example: set the current worst CQI The poor CQI needs to meet the QoS requirements of 98% of the UEs, then the base station judges whether the ratio of the number of the worst CQIs lower than the current worst CQI to the total number of CQIs is equal to or greater than 98% among all the CQIs it receives, and if so, it determines that the worst CQI is satisfied. Poor CQI adjustment condition, sort all CQIs lower than the current worst CQI from large to small, start counting from the first CQI after sorting, and calculate the ratio of the count value to the total CQI fed back by the UE, when the ratio When it is equal to 98%, update the current worst CQI with the minimum CQI corresponding to the ratio, otherwise, update the current worst CQI with the minimum CQI corresponding to the first ratio greater than 98%; The worst CQI adjustment condition keeps the current worst CQI unchanged.

Further, the base station may pre-set a range [A, B] for the current worst CQI, and when the updated current worst CQI exceeds the range, use the critical value of the range as the current CQI. For example: if the updated current worst CQI is smaller than A, A is used as the current worst CQI; if the updated current CQI is greater than B, B is used as the current worst CQI.

Step 107: The base station detects that the time slot for delivering the current worst CQI arrives, and broadcasts the current worst CQI on the downlink MICH.

Step 108: The base station detects that the time slot for sending MBMS data arrives, and sends the MBMS data according to the current worst CQI.

There is a one-to-one correspondence between the CQI, the MCS used by the MBMS data, and the data rate of the MBMS. After determining the current worst CQI, the base station can adjust the MCS used by the MBMS data according to the CQI.

It can be seen from the first embodiment shown in Figure 1 that the base station sends the current worst CQI to the UE, which can make the UE use the worst CQI as a reference value, and only when the measured CQI satisfies the feedback condition, it will feed back the CQI to the base station , thereby greatly saving signaling overhead and improving the utilization of channel resources.

Figure 2 is a schematic diagram of a specific example of the application of Embodiment 1 of the present invention. As shown in Figure 2, the time slot allocated by the base station for the UE in the connected state to feed back the CQI is time slot 2, and the time slot allocated for sending the current worst CQI is time slot 4, the time slot allocated for sending MBMS data is time slot 5, and the UE in the idle state can use any one of time slots 1 to 3 to feed back the CQI.

Since the delay of CQI feedback through the uplink DCH is lower than the delay of CQI feedback through the uplink RACH, in order to further reduce unnecessary CQI feedback, when the base station determines that all CQI feedback through the uplink DCH has been received in the current frame, The current worst CQI can be broadcast immediately to avoid unnecessary CQI fed back through the uplink RACH. Provide following embodiment according to this thought:

Embodiment two:

Fig. 3 is the flow chart of transmitting MBMS data provided by Embodiment 2 of the present invention, as shown in Fig. 3, its specific steps are as follows:

The process of the UE feeding back the CQI and the base station determining the current worst CQI in steps 301-306 is the same as steps 101-106 in the first embodiment.

Step 307: The base station determines that all CQIs fed back through the uplink DCH have been received, and then broadcasts the current worst CQI through the downlink MICH.

Since the time slot for feeding back the CQI through the uplink DCH is a fixed time slot, the base station can determine that all the CQI fed back through the uplink DCH have been received when the fixed time slot has expired.

Steps 308-309 are the same as steps 107-108.

It can be seen from the embodiment shown in Figure 3 that since the base station broadcasts the current worst CQI in time when receiving all the CQI fed back through the uplink DCH, the UE can determine whether to feed back the CQI according to the latest current worst CQI. CQI, further reducing unnecessary CQI feedback.

Figure 4 is a schematic diagram of a specific example of the application of Embodiment 2 of the present invention. As shown in Figure 4, the time slot allocation in this figure is the same as that in Figure 2, and at the same time, time slot 2 is used as the current worst CQI associated with the DCH time slot, so that the number of CQI fed back through time slot 3 can be reduced.

After the base station determines the current worst CQI, unless the base station receives worse CQI feedback from the UE, the base station will always send MBMS data according to the current worst CQI. However, the channel quality of the UE may improve. If the base station Sending MBMS data based on the current worst CQI will cause a waste of channel resources. Therefore, in order to further improve the utilization of channel resources, the base station can increase the current worst CQI when it has not received the CQI fed back by the UE for a period of time. value, so as to improve the transmission efficiency of MBMS data; or, adjust the current worst CQI value according to the statistical value of the CQI fed back by the UE every predetermined period of time. Two examples of adjusting CQI are given below:

Embodiment three:

Fig. 5 is the flow chart of transmitting MBMS data provided by Embodiment 3 of the present invention, as shown in Fig. 5, its specific steps are as follows:

Step 501: The base station detects that no UE feedback CQI has been received within a predetermined number of consecutive frames, determines that the current worst CQI value will be increased, and calculates the current worst CQI to be used according to the preset adjustment step size, and then The current worst CQI to be used is broadcast on the downlink MICH.

Step 502: The UE detects the current worst CQI to be used on the downlink MICH, judges whether the CQI measured by itself satisfies the feedback condition according to the CQI, and if so, executes step 503; otherwise, goes to step 505.

Step 503: UE feeds back its own CQI to the base station.

Step 504: The base station adjusts the current worst CQI to be used according to the CQI fed back by the UE, broadcasts the adjusted current worst CQI on the downlink MICH, and transmits MBMS data according to the adjusted current worst CQI, and the process ends.

In this step, the process of the base station adjusting the current worst CQI to be adopted according to the CQI fed back by the UE is the same as steps 105-106 shown in FIG. 1 .

Step 505: The base station determines that no CQI fed back by the UE has been received, then determines that the current worst CQI to be used is the current worst CQI, and transmits MBMS data according to the current worst CQI.

Embodiment four:

FIG. 6 is a flow chart of transmitting MBMS data provided by Embodiment 4 of the present invention. As shown in FIG. 6, the specific steps are as follows:

Step 601: The base station presets two arrays: a high group and a low group.

Step 602: the base station receives the CQI fed back by the UE, and detects that the difference between the CQI and the current worst CQI is within a predetermined range.

For example: the base station can preset: when the difference between the CQI fed back by the UE and the current worst CQI is in [-3, 0]db, determine that the CQI fed back by the UE is a low-group CQI; When the difference of the difference CQI is [0, 3]db, it is determined that the CQI fed back by the UE is the high group CQI.

Step 603: the base station judges whether the CQI fed back by the UE is higher than the current worst CQI, if yes, execute step 604; otherwise, execute step 605.

Step 604: The base station puts the CQI into the high group, and goes to step 606.

Step 605: the base station puts the CQI into the low group.

Step 606: The base station determines that it is time to adjust the CQI, and judges whether the number of CQIs in the low group is 0, and if so, executes step 607; otherwise, executes step 608.

Step 607: The base station increases the value of the current worst CQI according to the worst CQI in the high group and the preset adjustment step, clears the CQI in the high group and the low group, and transmits MBMS data according to the current worst CQI. This process Finish.

Step 608: The base station reduces the value of the current worst CQI according to the worst CQI in the low group and the preset adjustment step, clears the CQIs in the high group and the low group, and transmits MBMS data according to the current worst CQI.

The base station can also adjust the value of the current worst CQI according to the ratio r of the number of CQIs contained in the high group and the number of CQIs contained in the low group, for example: when r>a, increase the value of the current worst CQI; When r<b, reduce the value of the current worst CQI; when b≤r≤a, do not adjust the current worst CQI. Here, a and b can be set by the base station itself or sent to the base station after being set by the MBMSRAN controller.

Since the UE can receive MBMS data from multiple base stations at the same time, when each base station uses an MCS with the same modulation mode and compatible time slots or subcarriers when sending MBMS data, the UE will obtain macro-diversity gain and select The base station for high code rate MCS transmission can save resources to carry other services. For this reason, the present invention provides following embodiment:

Embodiment five:

FIG. 7 is a flow chart of transmitting MBMS data provided by Embodiment 5 of the present invention. As shown in FIG. 7, the specific steps are as follows:

Step 701: The MBMS RAN controller divides all MBMS-supporting base stations into one or more areas.

Specifically, the division may be performed according to the location of the base station or the routing area of the base station.

Step 702: The MBMS RAN controller assigns the same modulation mode to base stations belonging to the same area.

When the modulation mode in a certain area is changed, the MBMS RAN controller needs to notify all base stations in the area of the changed modulation mode at the same time.

Alternatively, the base stations in the same area determine the modulation mode to be used through negotiation.

The process of the UE feeding back the CQI and the base station determining the current worst CQI in steps 703-709 is the same as steps 101-107 in the first embodiment.

Step 710: The base station adjusts the code rate used in the current modulation mode according to the current worst CQI.

If the code rate is adjusted every time the current worst CQI is determined, the step of adjusting the code rate can be completed by the base station itself; if the code rate needs to be adjusted according to the statistical value of the current worst CQI, the step of adjusting the code rate can be performed by The MBMSRAN controller completes, and the specific process is: after the base station determines the current worst CQI, it sends the current worst CQI to the MBMSRAN controller, and the MBMS RAN controller performs statistics on the current worst CQI sent by the base station. For example: calculate the average value etc., determine the code rate according to the statistical value, and send the obtained code rate to the base station.

Step 711: The base station encodes the MBMS data, detects the arrival of the time slot for sending MBMS data, and selects the transmission code block corresponding to the current code rate and the transmission code block corresponding to the high code rate according to the current code rate and the principle that the transmission code block corresponding to the high code rate is compatible. MBMS data coding block, and deliver the selected MBMS data coding block.

It can be seen from the embodiment shown in Figure 7 that for base stations in the same area, the modulation schemes used by each base station are the same, and each base station adjusts its own code rate according to its own current worst CQI. When transmitting a coded block, for the same For different base stations in the area, the coded blocks transmitted by the base station with a low code rate can be compatible with the coded blocks transmitted by the base station with a high code rate, which not only improves the utilization of channel resources, but also improves the macro-diversity gain obtained by the UE.

In addition, for the embodiment shown in FIG. 7 , for the base stations belonging to the same area, when the current worst CQI values of the neighboring base stations of a base station are all low, that is, the neighboring base stations choose to have more transmission codes When the low-rate MCS of a block transmits MBMS data, the UE can obtain a higher diversity gain from the adjacent base station, so that the base station can select an MCS with a higher code rate, saving resources of the base station. Provide the embodiment that realizes this method below:

Embodiment six:

FIG. 8 is a flow chart of transmitting MBMS data provided by Embodiment 6 of the present invention. As shown in FIG. 8, the specific steps are as follows:

In steps 801-808, the process of the UE feeding back the CQI and the base station judging whether the CQI satisfies the adjustment condition is the same as the steps 701-708 in the fifth embodiment.

Step 809: the base station adjusts its own current worst CQI according to its own current worst CQI and the current worst CQI sent by its neighboring base stations.

Specifically, a corresponding relationship between the current worst CQI of a neighboring base station and the adjustment step size can be set in advance for each base station, and the base station finds the adjustment step size in the corresponding relationship according to the current worst CQI sent by the neighboring base station. , so as to adjust its current worst CQI.

Step 810: the base station sends its current worst CQI to other base stations belonging to the same area as itself.

Or, if there is no intercommunication interface between the base stations, the base station can also send its current worst CQI to other base stations through the MBMS RAN controller.

Step 811: The base station detects that the time slot for delivering the current worst CQI arrives, and broadcasts the current worst CQI on the downlink MICH.

Steps 812-813 are the same as steps 710-711.

Fig. 9 is a schematic diagram of an example of implementing the sixth application of the present invention. As shown in Fig. 9, when base stations A and B located in the same area decode the same MBMS data, each base station uses a Turbo decoder with a code rate of 1/N. Assuming that the decoded data is divided into M blocks, when base station A determines that the decoding rate used by base station B when transmitting MBMS data is 1/6 according to the CQI fed back by UE, base station A can use the decoding rate used by itself when transmitting MBMS data The rate is adjusted to 1/4, and the saved time slots are allocated to other services such as high-speed downlink packet access (HSDPA) services.

FIG. 10 is a system composition diagram of MBMS data transmission provided by an embodiment of the present invention. As shown in FIG. 10 , it mainly includes: UE101 and base station 102, wherein:

UE101: measure its own CQI, and feed back the CQI to base station 102 when the CQI meets the feedback condition.

The base station 102: receives the CQI fed back by the UE 101, determines the current worst CQI according to the CQI, and transmits MBMS data according to the worst CQI.

As shown in Figure 10, the MBMS transmission system may further include: RAN controller 103, which divides all base stations into more than one area, assigns the same modulation mode to base stations in each area, and sends the modulation mode to each base station;

Correspondingly, the base station 102 further selects the code rate of the current modulation scheme according to the current worst CQI, and selects the MBMS data code for transmission according to the code rate and the principle that the transmission coding block corresponding to the low code rate is compatible with the transmission coding block corresponding to the high code rate. piece.

Alternatively, the RAN controller divides all base stations into more than one area, assigns the same modulation mode to the base stations in each area, receives the current worst CQI sent by the base station, and selects a code rate for the base station according to the current worst CQI, and sets The code rate is sent to the base station;

Correspondingly, the base station 102 further sends the current worst CQI to the RAN controller, receives the code rate sent by the RAN controller, and according to the code rate and the transmission coding block corresponding to the low code rate are compatible with the transmission coding block corresponding to the high code rate In principle, MBMS data encoding blocks are selected for transmission.

FIG. 11 is a schematic structural diagram of a base station for MBMS data transmission provided by an embodiment of the present invention. As shown in FIG. 11 , it mainly includes: a worst CQI determination module 1021 and an MBMS transmission module 1022, wherein:

Worst CQI determination module 1021: receives the CQI fed back by UE101, determines the current worst CQI according to the CQI, and sends the current worst CQI to the MBMS transmission module 1022.

The worst CQI determination module 1021 further broadcasts its current worst CQI.

And/or, the worst CQI determination module 1021 further does not receive any UE feedback CQI within a predetermined number of consecutive frames, then according to the preset adjustment step size, increase the value of the current worst CQI, and broadcast the increased The current worst CQI value determines whether the CQI fed back by the UE is received within a predetermined period of time, and if so, readjusts the current worst CQI according to the CQI fed back by the UE; otherwise, keeps the increased current worst CQI unchanged.

Or, after receiving the CQI fed back by UE101, the worst CQI determination module 1021 further judges whether the difference between the CQI and the current worst CQI is within a preset positive number range, and if so, puts the CQI into the preset In the first array; otherwise, judge whether the difference between the CQI and the current worst CQI is within the preset negative range, if so, put the CQI into the preset second array; detect that the current worst CQI that meets the preset The poor CQI adjustment condition is to adjust the current worst CQI according to the CQIs in the first array and the second array.

And/or, the worst CQI determination module 1021 further adjusts its own current worst CQI according to the current worst CQI sent by the neighboring base station using the same modulation mode as itself, and sends the adjusted own current worst CQI to its own neighboring base stations.

The MBMS transmission module 1022: receives the current worst CQI sent by the worst CQI determination module 1021, and transmits MBMS data according to the CQI.

The MBMS transmission module 1022 further determines the code rate of the current modulation mode according to the current worst CQI sent by the worst CQI determination module 1021 .

The above descriptions are only process and method embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (24)

1. A multimedia broadcast multicast service MBMS transmission method, is characterized in that, comprises: The user equipment UE measures its own channel quality indicator value CQI, and when its own CQI meets the feedback conditions, feeds back the CQI to the base station, and the base station determines the current worst CQI according to the CQI fed back by the UE, and uses the current worst CQI to transmit MBMS data . 2. The method according to claim 1, wherein after the UE measures its own CQI, it further comprises: when the UE determines that the statistical condition is satisfied, the UE performs statistics on the measured CQI, and judges whether the statistically obtained CQI meets the requirements. Feedback condition, if yes, determine that its own CQI satisfies the feedback condition. 3. The method according to claim 1, wherein the base station determining the current worst CQI comprises: the base station judges whether the CQI fed back by the UE is lower than its own current worst CQI, and if so, updates the current worst CQI with the CQI fed back by the UE. Worst CQI; Or, the base station judges whether the ratio of the number of the worst CQIs lower than its own to the number of all the CQIs received among all the received CQIs satisfies the preset ratio, and if so, the base station that satisfies the preset ratio is lower than The minimum value among the CQIs of the current worst CQI updates the current worst CQI. 4. The method according to claim 1, wherein after the base station determines the current worst CQI, it further comprises: the base station broadcasts the current worst CQI. 5. The method according to claim 4, wherein the CQI satisfies the feedback condition as follows: the CQI is lower than the current worst CQI received by the UE last time from the base station, or the CQI is the same as the last worst CQI received by the UE. The obtained difference of the current worst CQI from the base station is within a preset range. 6. The method according to claim 4, wherein the UE feeds back the CQI to the base station as follows: when the UE is in the connected state, the UE feeds back the CQI to the base station through a pre-allocated uplink dedicated channel DCH; when the UE is in the In the idle state, the UE feeds back the CQI to the base station through the pre-assigned uplink random access channel RACH; Before the base station determines the current worst CQI, it further includes: the base station receives all CQIs fed back through the uplink DCH. 7. The method according to claim 1, further comprising: the base station does not receive any UE feedback CQI within a predetermined number of consecutive frames, and then increases the current maximum The value of the difference CQI. 8. The method according to claim 7, characterized in that, after the base station increases the value of the current worst CQI, it further comprises: the base station broadcasts the increased current worst CQI value, and judges whether the UE receives the CQI within a predetermined period of time. For the fed back CQI, if yes, readjust the current worst CQI according to the CQI fed back by the UE; otherwise, keep the added current worst CQI unchanged. 9. The method according to claim 1, wherein the base station determining the current worst CQI comprises: A. The base station judges whether the difference between the CQI fed back by the UE and the current worst CQI is within the preset positive number range. If it is, put the CQI into the first preset array and execute step B; if not, Judging whether the difference between the CQI and the current worst CQI is within the preset negative range, if so, putting the CQI into the preset second array, and performing step B, otherwise, directly performing step B; B. The base station detects that the preset current worst CQI adjustment condition is satisfied, adjusts the current worst CQI according to the CQIs in the first array and the second array, and takes the adjusted CQI as the current worst CQI. 10. The method according to claim 9, wherein the base station adjusting the current worst CQI in step B comprises: the base station judges whether the second array contains CQI, if so, according to the worst CQI in the second array, Decrease the value of the current worst CQI; otherwise, increase the value of the current worst CQI according to the worst CQI in the first array. 11. The method according to claim 9, wherein the adjustment of the worst CQI by the base station in step B comprises: the base station judges whether the ratio of the number of CQIs saved in the first array to the number of CQIs saved in the second array is greater than the first preset value, if so, increase the value of the current worst CQI; otherwise, determine whether the ratio of the number of CQIs saved in the first array to the number of CQIs saved in the second array is less than the second preset value, if , reduce the value of the current worst CQI. 12. The method according to claim 1, further comprising: dividing all base stations into more than one area in advance, and setting base stations belonging to the same area to use the same modulation method at the same time; The base station transmitting MBMS data according to the current worst CQI includes: the base station encodes the MBMS data, determines the code rate of the current modulation mode according to the current worst CQI, and transmits the code block corresponding to the low code rate according to the determined code rate Compatible with the principle of transmitting coded blocks corresponding to high code rates, select the coded blocks for transmission, and send the selected coded blocks to the UE. 13. The method according to claim 1, further comprising: dividing all base stations into more than one area in advance, and setting base stations belonging to the same area to use the same modulation method at the same time; The transmission of MBMS data by the base station according to the current worst CQI includes: the base station encodes the current MBMS data, and sends the current worst CQI to the MBMS radio access network RAN controller, and the MBMS RAN controller determines the current worst CQI according to the current worst CQI. The code rate of the modulation mode is sent to the base station. The base station selects the code block for transmission according to the code rate and the principle that the transmission code block corresponding to the low code rate is compatible with the transmission code block corresponding to the high code rate. The coded block is sent to the UE. 14. methods as claimed in claim 1 or 12 or 13, it is characterized in that, After the base station determines the current worst CQI, it further includes: the base station adjusts its own current worst CQI according to the current worst CQI sent by the neighboring base station using the same modulation mode as itself, and sends the adjusted current worst CQI of itself sent to its neighboring base stations. 15. A multimedia broadcast multicast service MBMS transmission system is characterized in that, comprising: user equipment UE and base station, wherein: The UE measures its own channel quality indicator CQI, and feeds back the CQI to the base station when its own CQI meets the feedback condition; The base station receives the CQI fed back by the UE, determines the current worst CQI according to the CQI, and transmits MBMS data according to the worst CQI. 16. The system according to claim 15, further comprising: a radio access network (RAN) controller, configured to divide all base stations into more than one area, and assign the same modulation to base stations in each area mode, sending the modulation mode to each base station; The base station further selects the code rate of the current modulation scheme according to the current worst CQI, and selects the transmission code block from the MBMS data code blocks according to the principle that the transmission code block corresponding to the low code rate includes the transmission code block corresponding to the high code rate. 17. The system according to claim 15, wherein the system further comprises: a RAN controller, which divides all base stations into more than one area, assigns the same modulation mode to the base stations in each area, and receives the signals sent by the base stations. The current worst CQI of , select a code rate for the base station according to the current worst CQI, and send the code rate to the base station; The base station further sends the current worst CQI to the RAN controller, receives the code rate sent by the RAN controller, and according to the code rate and the principle that the transmission coding block corresponding to the low code rate is compatible with the transmission coding block corresponding to the high code rate, Select the transport coding block among the MBMS data coding blocks. 18. A base station carrying out multimedia broadcast multicast service MBMS transmission, is characterized in that, comprises: worst channel quality indicator CQI confirms module and MBMS transmission module, wherein: The worst CQI determination module receives the CQI fed back by the user equipment UE, determines the current worst CQI according to the CQI, and sends the current worst CQI to the MBMS transmission module; The MBMS transmission module receives the current worst CQI sent by the worst CQI determination module, and transmits MBMS data according to the CQI. 19. The base station according to claim 18, wherein the worst CQI determination module further broadcasts its own current worst CQI. 20. The base station according to claim 18, wherein the worst CQI determination module further does not receive any UE feedback CQI within a predetermined number of consecutive frames, and then increases the current CQI according to a preset adjustment step size The value of the worst CQI. 21. The base station according to claim 20, wherein the worst CQI determining module further broadcasts the increased current worst CQI value, and judges whether the CQI fed back by the UE is received within a predetermined duration, and if so, according to The CQI fed back by the UE readjusts the current worst CQI; otherwise, the added current worst CQI remains unchanged. 22. The base station according to claim 18, wherein the worst CQI determination module further receives the CQI fed back by the UE, and judges whether the difference between the CQI and the current worst CQI is within a preset positive number range , if it is, put the CQI into the preset first array; otherwise, judge whether the difference between the CQI and the current worst CQI is within the preset negative range, if so, put the CQI into the preset first array In the second group: it is detected that the preset current worst CQI adjustment condition is met, and the current worst CQI is adjusted according to the CQIs in the first group and the second group. 23. The base station according to claim 18, wherein the MBMS transmission module further determines the code rate of the current modulation mode according to the current worst CQI sent by the worst CQI determination module, according to the code rate, and the low The transmission coding block corresponding to the code rate is compatible with the principle of the transmission coding block corresponding to the high code rate, and the transmission coding block is selected among the MBMS data coding blocks. 24. The base station according to claim 18, wherein the worst CQI determination module further receives the current worst CQI sent by a neighboring base station using the same modulation mode as itself, and adjusts its own current worst CQI according to the CQI. difference CQI, and send the adjusted current worst CQI to its neighboring base stations.

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