CN1960568A - Method for reducing data transmission delay of switching sectors - Google Patents
Method for reducing data transmission delay of switching sectors Download PDFInfo
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- CN1960568A CN1960568A CNA2005101200735A CN200510120073A CN1960568A CN 1960568 A CN1960568 A CN 1960568A CN A2005101200735 A CNA2005101200735 A CN A2005101200735A CN 200510120073 A CN200510120073 A CN 200510120073A CN 1960568 A CN1960568 A CN 1960568A
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Abstract
The method comprises: for user just switched into a new cell, the base station decides its transmission mode; if the base station selects a local type data transmission mode comprising temporarily distributed transmission, it still needs to decide the time of temporarily distributed transmission; the base station sends the indication of local type data transmission mode and the time indication of temporarily distributed transmission to the user device; in a defined time, the base station uses the distributed data transmission mode to transmit data to user device; when the defined time is over, the downlink data is switched into local type transmission mode from the temporarily distributed transmission. By using temporarily distributed transmission mode, the time delay of getting data transmission physical resources by new cell will be reduced.
Description
Technical field
The present invention relates to OFDM (OFDM) wireless communication system, particularly reduce the method for OFDM wireless communication system data transmission delay of switching.
Background technology
Now, third generation partner plan (being called for short 3GPP) standardization body has set about beginning its existing system standard is carried out long-term evolution (being called for short LTE).In the middle of numerous physical layer transmission technology, technology is with its higher availability of frequency spectrum for OFDM (being called for short OFDM), and lower processing complexity becomes in all descending schemes more promising a kind of.
Be a kind of multi-carrier modulation communication technology on the OFDM technological essence, its basic principle is the data flow of a two-forty to be decomposed into several rate data streams transmit simultaneously on one group of mutually orthogonal subcarrier.The OFDM technology is because its multicarrier character has performance advantage aspect a lot.(1) significant advantage of OFDM technology is because data parallel transmission on a plurality of subcarriers respectively, and the length of the symbol on each subcarrier increases accordingly, and is insensitive to channel delay; Add protection on each symbol at interval by further giving, promptly introduce Cyclic Prefix (being called for short CP), under the situation of channel delay, can eliminate intersymbol interference (ISI) fully less than circulating prefix-length.Like this, each subcarrier has all experienced flat fading channel.(2) availability of frequency spectrum height of OFDM technology, ofdm signal are actual on frequency domain an overlapping, and this overlapping on improved the availability of frequency spectrum to a great extent.(3) ability of the anti-narrow band interference of OFDM technology and frequency selective fading is stronger.Can make OFDM have frequency diversity and time diversity effect by chnnel coding with interweaving, thereby resist narrow band interference and frequency selective fading effectively.(4) modulation of OFDM technology can realize by baseband I FFT conversion, and IFFT/FFT has ripe quick calculation method, can realize in dsp chip and hardware configuration easily.
In the OFDM wireless transmitting system, exist two kinds of transmission modes: local formula transmission mode and distributed transmission pattern.In the downlink data transmission process:
For local formula transmission mode, the channel quality of each sub-band of subscriber equipment on will the measuring system frequency range, the channel quality indication (CQI) that will measure each sub-band is then reported and is given the base station.The base station will be according to the current load of CQI and system of each subscriber equipment report after having received the CQI that measures, and whether decision gives the user equipment allocation frequency resource, and carries out transfer of data for those local frequency ranges of user equipment allocation.In the process of transfer of data, subscriber equipment also will continue the channel quality on each sub-band on the measuring system frequency range, and send the CQI measure to the base station, with the frequency scheduling that realizes transfer of data and Adaptive Modulation and Coding (AMC) thus the throughput of maximum data transfer.
For the distributed transmission pattern, subscriber equipment can be measured an average channel quality on the whole system frequency range, and then that this is single average CQI reports to the base station.The base station will determine whether to the distributed frequency resource of this user equipment allocation according to each user's the current load of CQI and system after having received this average CQI.In the process of transfer of data, subscriber equipment equally also will continue the average CQI on the measuring system whole frequency, and send the CQI value measure to the base station, with the frequency scheduling that realizes transfer of data and Adaptive Modulation and Coding (AMC) thus the throughput of raising transfer of data.
From top description as can be seen, under the local formula transmission mode, subscriber equipment is CQI on a plurality of sub-bands to the measurement report of base station transmits, and under the distributed transmission pattern, subscriber equipment only sends single average CQI to the base station.Therefore, the information bit of the CQI of the required transmission of local transmission pattern will be far longer than the required information bit of distributed transmission pattern.
Usually in order to reduce to control the influence of signaling to the data throughput, CQI will send with certain cycle, and the information bit of transmission CQI is many more, and the cycle that sends so accordingly also can be long more.In addition, not too large in order to make user's equipment send the transmitted power of channel of CQI usually according to the CQI reporting mechanism of using in the existing high speed downlink packet access technology (HSDPA), can adopt and repeatedly retransmit CQI, to guarantee that CQI can correctly receive.Be appreciated that if transmit the required information bit of CQI manyly more, the time of corresponding correct reception CQI also can be long more.
Therefore, be appreciated that under the local formula transmission mode that the time that the base station receives the CQI report will be far longer than the time that CQI reports that receives under the distributed mode.
According to the discussion of present 3GPP in LTE, for the complexity that the reduction system realizes, the subscriber equipment that switches for the sub-district will not re-use soft hand-off in downlink transmission process.Therefore do not had after the soft handover, wishing has some new mechanism to improve the performance that is in subscriber equipment in the cell switch process.
Subscriber equipment is in handoff procedure, the base station of new sub-district will be better than the channel quality of former cell base station to subscriber equipment to the channel quality of subscriber equipment, therefore it is fast more that this user obtains the speed of physical resource in new sub-district, it is more little to the interference that other users produce so, and the data transmission performance of oneself is also good more.Therefore reduce to switch the time that the user obtains physical resource in new sub-district, will improve the performance of switching user and system.
And in the OFDM wireless system, owing to have local formula transmission mode and a distributed transmission pattern, therefore when subscriber equipment switches to new sub-district, will exist dual mode to determine transmission mode in new sub-district:
Mode 1: determine transmission mode in the new sub-district according to the transmission mode in former sub-district.
If what this user adopted in former sub-district is local formula transmission mode, the initial transmission phase in new sub-district also adopts local formula transmission mode so; And if what adopt is the distributed transmission pattern, also adopt the distributed transmission pattern in the starting stage of new sub-district so in former sub-district.
Mode 2: in new sub-district, carry out new measurement, with the transmission mode of determining in switching cell, to be fit to.
Do not consider transmission mode, carry out new measurement,, select the transmission mode that is fit to according to specific choice mechanism in new sub-district in former sub-district.
No matter be mode 1 or mode 2, if subscriber equipment adopts local formula transmission mode at new community user equipment, subscriber equipment will send the CQI information of a plurality of sub-bands to the base station so, therefore with respect to the distributed transmission pattern, the signaling bit of corresponding required transmission is more, it is also more to receive the required time, and the time delay of transfer of data is bigger in the time of so all will causing switching to new sub-district.
For mode 2, when just being linked into new sub-district, also to there be a subscriber equipment to make measurement report to the base station, the process of base station selected transmission mode, this will further increase subscriber equipment obtains physical resource in new sub-district time delay.
Distributed and the local formula downlink data transmission time delay schematic diagram of mode 1 and mode 2, as depicted in figs. 1 and 2.
Because the time delay that obtains physical resource in new sub-district is bigger, will cause this user in the channel condition prolongation of relatively poor former cell transmission time, has so both worsened this user's self data transmission performance, has increased its interference to the neighbor cell user again.
Summary of the invention
For achieving the above object, the present invention proposes a kind of switching user in sub-district obtains transfer of data physical resource time delay in new sub-district method that reduces.
For achieving the above object, a kind of method that reduces data transmission delay of switching sectors comprises step:
A) go into the user of new sub-district for firm switching, the transmission mode that it is fit to is determined in the base station, if the base station selected local formula data-transmission mode that comprises interim distributed data transmission, the interim distributed data transmission time also will be determined in the base station;
B) base station will comprise the local formula data-transmission mode indication of interim distributed transmission and subscriber equipment is issued in the time indication of interim distributed data transmission;
C) in the determined time period, the base station will utilize the distributed transmission pattern to send data to subscriber equipment provisionally;
D) after when being timed to, downlink data transmission will change local formula transfer of data over to by interim distributed data transmission.
The present invention proposes a kind of local transmission pattern that comprises interim distributed transmission, make and switch to the user of new sub-district before not obtaining local formula physical resource, with a kind of provisional distributed transmission mode transfer data, like this under the prerequisite that does not increase local formula propagation delay time, reduced to obtain the time delay of transfer of data physical resource in new sub-district, thereby improved the performance of data traffic transmission, reduced to switch the interference of user neighbor cell.
Description of drawings
Fig. 1 is distributed and local formula downlink data transmission time delay schematic diagram;
Fig. 2 is the distributed and local formula downlink data transmission time delay schematic diagram that transmission mode selection is arranged in new sub-district;
Fig. 3 is the local formula transmission mode implementation step that comprises interim distributed data transmission;
Fig. 4 is that distributed, local formula compares schematic diagram with the local formula transmission mode that comprises interim distributed transmission,
Embodiment
The present invention proposes a kind of user obtains transfer of data physical resource time delay in new sub-district method that reduces to switch.
At first provided a kind of new downlink data transmission pattern when being used for subscriber equipment and just having switched to new sub-district, this pattern is a kind of local formula transmission mode that comprises interim distributed transmission pattern.Under this pattern, if when in new sub-district, selecting local formula transmission mode to be used for the downlink data transmission of subscriber equipment, subscriber equipment at first can send data with interim distributed transmission pattern in the regular hour section, afterwards again with local formula transmission mode transmission data.
It is pointed out that the time of interim distributed transmission mode transfer, set, thereby need not new instruction by interim distributed transmission pattern to the conversion of local formula transmission mode and indicate by timer.And the time that timer sets, by the high level indication, its value will be more than or equal to finishing once the local required time of formula transmission mode CQI transmission.This time can be determined the channel quality measurement of new sub-district and the demand of this transfer of data data volume in former sub-district according to subscriber equipment.Channel quality measurement can be known two kinds of gain difference between the transmission mode, and the difference of this gain is big more, and the relative efficiency of transmission of so local formula transmission mode is high more.Therefore the data volume demand is big more, and two kinds of mode transfer gain difference are big more, and the time of respective settings is also just short more so.
In addition, when the interim distributed transmission pattern of transmission, subscriber equipment can send the CQI report of local formula transmission mode simultaneously, can shorten like this by the change-over time of interim distributed transmission to local formula transmission mode.
When being given in the subscriber equipment that is applicable to local formula transmission mode in the new sub-district below and initially switching to new sub-district, utilize the concrete implementation step of the transmission mode transmission data that proposed, as shown in Figure 3.
301, between subscriber equipment and the new cell base station that switches to, set up control channel, and according to the transmission mode of subscriber equipment before switching or the measurement before switching determine the downlink data transmission pattern that this user is fit to;
302, the data-transmission mode indication will be transmitted to subscriber equipment in the base station.Possible transmission mode has two kinds, and a kind of is the distributed transmission pattern, and is another kind of for comprising the local formula transmission mode of interim distributed transmission pattern.If be the distributed transmission pattern, so follow-up will be with existing distributed data transfer mode transmission data.And if for comprising the local transmission pattern of interim distributed transmission pattern, the timing time of the transmission timer of interim local formula transmission mode also will be specified in the base station except indicating transmission mode.To continue afterwards by following execution in step;
303, subscriber equipment will be opened timer and be begun to send to the base station CQI report of distributed transmission pattern after having received pattern indication and the indication of timer settings time;
304, the distributed resource that downlink data transmission is used is determined according to Distributed C QI report in the base station, and the Adaptive Modulation and Coding mode that is adopted according to the transmission of CQI report specified data, and with employed resource and Adaptive Modulation and Coding mode notifying user equipment;
305, the base station adopts selected modulation coding mode to send data to subscriber equipment on determined distributed resource.Repeat 303,304 and 305 afterwards then until the distributed transmission timer;
306, interim distributed transmission timer then before, subscriber equipment just can start the local formula CQI measurement report to the base station;
307, when interim distributed transmission timer to constantly, interim distributed transmission finishes, downlink data transmission changes local formula distributed transmission over to;
308, the local formula CQI measurement report before the basis of base station, definite local formula resource that is fit to and suitable Adaptive Modulation and Coding mode, and with determined resource and modulation coding mode notifying user equipment;
309, the base station adopts selected modulation coding mode to send data to subscriber equipment on determined local formula resource.
310, subscriber equipment continues to send local formula CQI to the base station and reports.Repeating step 309 and 310 finishes until local formula transmission mode afterwards.
Embodiment
For the inventive method is described, provide the embodiment of the inventive method below.In the present embodiment, suppose that the transmission mode that subscriber equipment was fit to that switches to new sub-district is local formula transmission mode.In order to shorten the time delay that this subscriber equipment obtains the transfer of data physical resource, the local formula transmission mode transmission data that comprise interim distributed transmission that proposed will be adopted.
In this embodiment, the time that sets in the interim distributed transmission timer is to finish once the local required time of formula transmission mode CQI transmission.
In Fig. 4, provided the distributed transmission pattern, the comparison schematic diagram of the local formula transmission mode that comprises interim distributed transmission among local formula transmission mode and this embodiment.
As can be seen from the figure, utilize the transmission mode that is proposed,, therefore can in the time period of the local formula CQI of transmission, carry out report and the distributed data transmission of Distributed C QI simultaneously because the time of the local formula transmission mode CQI of transmission is longer.Like this, under the prerequisite of the gain that the time delay that does not influence local formula transmission mode and local formula transmission mode are obtained, in the time period of the local formula CQI of transmission, inserted the distributed data transmission, shortened the time delay of subscriber equipment at new sub-district acquisition transfer of data physical resource, downlink data transmission in new sub-district has been obtained in advance, thereby reduced the interference of this switching user, improved the performance of system neighbor cell.
Claims (8)
1. method that reduces data transmission delay of switching sectors comprises step:
A) go into the user of new sub-district for firm switching, the transmission mode that it is fit to is determined in the base station, if the base station selected local formula data-transmission mode that comprises interim distributed data transmission, the interim distributed data transmission time also will be determined in the base station;
B) base station will comprise the local formula data-transmission mode indication of interim distributed transmission and subscriber equipment is issued in the time indication of interim distributed data transmission;
C) in the determined time period, the base station will utilize the distributed transmission pattern to send data to subscriber equipment provisionally;
D) after when being timed to, downlink data transmission will change local formula transfer of data over to by interim distributed data transmission.
2. method according to claim 1 is characterized in that described base station determines that its transmission mode that is fit to comprises two kinds, and a kind of is the distributed data transmission, and a kind of is the local formula data-transmission mode that comprises interim distributed transmission.
3. method according to claim 1, it is characterized in that if in former sub-district, use distributed mode, in new sub-district, also transmit so with distributed data, if and in former sub-district with local formula transfer of data, then in new sub-district with the local formula transmission mode transmission that comprises interim distributed transmission.
4. method according to claim 1 is characterized in that determining suitable transmission mode according to the metrical information to new sub-district in former sub-district.
5. method according to claim 1 is characterized in that interim distributed data transmission and the conversion between the local formula data-transmission mode are by the time control that sets.
6. according to claim 1) described method, it is characterized in that controlling the time that interim distributed data is transmitted by timer.
7. method according to claim 1 is characterized in that subscriber equipment also sends local formula CQI measurement report when carrying out the distributed data transmission.
8. method according to claim 1 is characterized in that the time of the time of interim distributed transmission more than or equal to the local formula CQI of transmission primaries.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CNA2005101200735A CN1960568A (en) | 2005-11-03 | 2005-11-03 | Method for reducing data transmission delay of switching sectors |
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| CNA2005101200735A CN1960568A (en) | 2005-11-03 | 2005-11-03 | Method for reducing data transmission delay of switching sectors |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101754396B (en) * | 2008-12-01 | 2012-06-27 | 电信科学技术研究院 | Method, system and device for indicating transmission mode |
| CN105991176A (en) * | 2015-01-30 | 2016-10-05 | 上海贝尔股份有限公司 | Method for improving channel quality feedback |
| CN112601250A (en) * | 2014-10-10 | 2021-04-02 | 瑞典爱立信有限公司 | Wireless device reporting |
| US11974273B2 (en) | 2023-01-30 | 2024-04-30 | Telefonaktiebolaget Lm Ericsson (Publ) | Wireless device reporting |
-
2005
- 2005-11-03 CN CNA2005101200735A patent/CN1960568A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101754396B (en) * | 2008-12-01 | 2012-06-27 | 电信科学技术研究院 | Method, system and device for indicating transmission mode |
| CN112601250A (en) * | 2014-10-10 | 2021-04-02 | 瑞典爱立信有限公司 | Wireless device reporting |
| CN105991176A (en) * | 2015-01-30 | 2016-10-05 | 上海贝尔股份有限公司 | Method for improving channel quality feedback |
| US11974273B2 (en) | 2023-01-30 | 2024-04-30 | Telefonaktiebolaget Lm Ericsson (Publ) | Wireless device reporting |
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