CN1881968B - Data transmission method for decreasing multipath delay interference - Google Patents
Data transmission method for decreasing multipath delay interference Download PDFInfo
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- CN1881968B CN1881968B CN200510076806XA CN200510076806A CN1881968B CN 1881968 B CN1881968 B CN 1881968B CN 200510076806X A CN200510076806X A CN 200510076806XA CN 200510076806 A CN200510076806 A CN 200510076806A CN 1881968 B CN1881968 B CN 1881968B
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Abstract
The invention relates to a data sending method for reducing the multi-path delay interference, which comprises: based on the modulated data signal, using the emit impulse model relative to the frequency block used to transmit said data signal, to generate one signal at one mark period that not comprises circle prefix CP; via judging if the multi-path delay expansion is larger than the length of circle prefix CP, to judge if needs to increase the length of circle prefix CP; if needs, repeating transmitting the signal as the increased circle prefix information to be sent out with the circle prefix CP; the signal sending method comprises: sending said signal at the tail of present mark and before the tail circle prefix signal of next mark, or sending said signal at the back of circle prefix of present mark and the most front of next mark. The invention can increase the length of circle prefix to reduce the interference of multi-path delay, based on different fading conditions and different users.
Description
Technical field
The present invention relates to technical field of data transmission, be meant a kind of data transmission method that multidiameter disturbs that reduces especially.
Background technology
Propose among the 3GPP WG1 motion R1-050254, in the transmission data, can adopt local single-carrier technology (localized single carrier) to transmit data.Local single-carrier technology promptly is to come carry data signals by the time domain waveform that belongs to a frequency chunks (chunk) on the frequency, shows the schematic diagram of local single carrier transmission data frequency piece as Fig. 1.For data transmission procedure, inevitably can produce the multipath of signal transmission.Multipath refers to, because the transmitting terminal signal in transmission course, produces the reason of reflection, diffraction, scattering by building, causes a receiving terminal can receive different amplitudes, phase place, the electromagnetic wave of the different times of advent.In general, different channel circumstance multidiameter varies in size.
During the transmission data,, can adopt the frequency domain equalization technology for the multipath that overcomes in the transmission course disturbs.In order to simplify frequency domain equalization, can increase Cyclic Prefix (CP) at each frequency chunks edge.When the length of Cyclic Prefix during greater than multidiameter big or small; Cyclic Prefix has protected the signal of previous symbol can not cause interference to the signal of next symbol; and after the recipient removes Cyclic Prefix; multipath effect just in time is a circular convolution on time-domain; thereby multipath effect is a product on frequency domain; therefore adopted behind the Cyclic Prefix and can carry out the demodulation of subscriber signal, and can utilize multipath effect to come received signal with the equilibrium of simple frequency territory.
Show the flow chart of present employing single-carrier technology transmission of data signals as Fig. 2, to the signal after the modulation, by the transmitted pulse moulding, add Cyclic Prefix again, launch, wherein the transmitted pulse moulding can utilize frequency-domain operations to realize, the step of transmitted pulse moulding can comprise: carry out the FFT conversion, be multiplied by the one-tenth type function p (f) of a frequency domain again, carry out the IFFT conversion again, wherein p (f) can be the frequency response of the root raised cosine filter of the frequency chunks correspondence of wanting data signal selected, FFT, IFFT is respectively fast fourier transform and the fast adverse Fourier transform that transmits the whole bandwidth of signal, and the inverse of FFT and IFFT subcarrier width promptly is the time span that does not comprise Cyclic Prefix that a frequency chunks takies.In this process, the step of structure symbol and CP is as follows:
With a symbol period is unit, the front end emission of each symbol period be Cyclic Prefix.A symbol period is defined as the time span that a frequency chunks (chunk) takies, and is similar to a symbol period in the ofdm system.As shown in Figure 3, what CP wherein represented is Cyclic Prefix, and this part signal is that the tail signal copy of a symbol period obtains, and the signal that this symbol period afterbody is identical with Cyclic Prefix is called afterbody Cyclic Prefix signal.
When CP adopted fixing value, because the difference of occurring in nature decline, the size that may occur multidiameter under the bigger situation of the delay ratio of fading channel surpassed the length of Cyclic Prefix.In addition, because the multipath of different user may be different, therefore when all users adopt same CP length, some user's multidiameter expansion also may be greater than the length of CP, thereby, can cause intersymbol interference, and can destroy the structure of multipath effect, cause multipath effect to influence the reception of receiving terminal signal as circular convolution.
Summary of the invention
In view of this, main purpose of the present invention has been to provide a kind of data transmission method that multidiameter disturbs that reduces, can be at different fading environment, different user, and the length that increases Cyclic Prefix neatly reduces the interference of multidiameter.
The data transmission method for uplink that reduces the multidiameter interference provided by the invention, to the signal after the modulation, produce a signal that does not comprise a symbol period of cyclic prefix CP by the transmitted pulse moulding, add cyclic prefix CP again, launch described CP and the described signal that does not comprise a symbol period of cyclic prefix CP, this method may further comprise the steps:
Reception is from the announcement information of base station, described notification message is used to notify terminal to determine that in described base station the window of multidiameter signal compares delay that common Cyclic Prefix requires during evening, launch first signal at the afterbody in current sign cycle, and at the first identical signal of preceding surface launching of the afterbody Cyclic Prefix of next symbol, the time span of the maximum that the time span that the delay that to be the window that is not less than described multidiameter signal require than common Cyclic Prefix of the length of described first signal is late or the system that reaches allow; Or, described notification message is used to notify terminal to compare delay that common Cyclic Prefix requires early the time at the window of determining the multidiameter signal, back surface launching secondary signal at the Cyclic Prefix of current sign, in the identical secondary signal of the forefront of next symbol emission, the time span that the delay that to be the window that is not less than the multidiameter signal require than common Cyclic Prefix of the length of described secondary signal is Zao or reach the time span of the maximum of system's permission; Or, the part that described notification message is used to notify terminal to compare the window of delay evening that common Cyclic Prefix requires and described multidiameter signal in the part of the window of determining the multidiameter signal is compared delay that common Cyclic Prefix requires early the time, launch the 3rd signal at the afterbody in current sign cycle, and at the 3rd identical signal of preceding surface launching of the afterbody Cyclic Prefix of next symbol, the length of the maximum that the time span that the delay that to be the window that is not less than the multidiameter signal require than common Cyclic Prefix of the length of described the 3rd signal is late or the system that reaches allow, and at back surface launching the 4th signal of the Cyclic Prefix of current sign, at the 4th identical signal of the forefront of next symbol emission, the time span that the delay that to be the window that is not less than the multidiameter signal require than common Cyclic Prefix of the length of described the 4th signal is Zao or reach the length of the maximum of system's permission.
The window of described multidiameter signal is: for the multipath signal that is received, and the signal time of measuring the time of the signal that receives the earliest and receiving the latest, the time difference of described two signals is as the window of described multidiameter signal
Wherein, described method also comprises:
Between one or more time transmission range, carry out the judgement of channel latency in (TTI).
Wherein, this method further comprises: described first signal carries the available information that needs send, or described secondary signal carries and need the available information that sends, or described the 3rd signal and the 4th signal carry and need the available information that sends.。
Wherein, this method is applied to the transfer of data of single carrier.
By said method as can be seen, the present invention during the transmission data, can increase the length that changes Cyclic Prefix at different fading environment, different user neatly in the single-carrier system of Cyclic Prefix.Can also flexibly Cyclic Prefix be increased before or after it according to multidiameter window and the morning or the evening that postpone usually.On the other hand, can utilize Cyclic Prefix to carry out the transmission of useful information.
Description of drawings
Fig. 1 is the schematic diagram of a frequency chunks of single carrier of part.
Fig. 2 is the flow chart of single-carrier technology transmission data.
Fig. 3 is the symbol that will transmit of prior art structure.
The schematic diagram that Fig. 4 changes for multidiameter.
Fig. 5 is the structure chart of the symbol of first kind of launching technique of the present invention.
Fig. 6 is the structure chart of the symbol of second kind of launching technique of the present invention.
Fig. 7 adjusts the flow chart of CP length transmission data for the present invention.
Embodiment
The invention provides a kind of transmission method of data, make and, can adjust flexibly the length of Cyclic Prefix (CP) as required during data in transmission, the size of avoiding occurring multidiameter surpasses the length of Cyclic Prefix and reduces the performance of demodulation.Transfer of data of the present invention comprises following steps:
First step: to the data-signal of modulation, utilize the selected transmitted pulse moulding that will transmit the frequency chunks correspondence of back data-signal of modulating, produce a signal that does not comprise a symbol period of cyclic prefix CP.
Second step: judge whether to increase the length of Cyclic Prefix, if by sending the length of the cyclic prefix information that repeating signal P is used as increasing, and send CP.
Judging whether to increase the length of Cyclic Prefix, is by the estimation of multidiameter expansion is carried out.After terminal sends a signal, can measure the multipath signal that receives at the place, base station, measure the time of the signal that receives the earliest, the signal time of Jie Shouing the latest, the time difference of described two multipath signals (also can be understood as from the signal that receives the earliest the time be carved into moment of the signal that receives the latest) be described multidiameter expansion or be called the time window of multidiameter signal.The base station judges whether to increase CP length and what increases then, adopts which kind of mode to increase, and is notified to user terminal, and terminal sends signal according to announcement information.
Wherein, measure the multidiameter signal can be according to two kinds of following different situations, adopt different dual modes to increase the length of Cyclic Prefix, wherein this process can be referring to the flow chart shown in Fig. 7.
As Fig. 4, for the active user, whether the window of its multidiameter signal is more late than the delay of common Cyclic Prefix requirement, if, then record late time span (t2-t3), adopt a in the following method (in the corresponding diagram 4 a), otherwise, if the window of this multidiameter signal is more more Zao than the delay that common Cyclic Prefix requires, record the time span (t4-t1) of morning, adopt b (b in the corresponding diagram 4) in the following method:
A: referring to Fig. 5, at the signal P of the tail end in current sign cycle emission certain-length, the identical P of emission before the afterbody Cyclic Prefix signal of next symbol.Wherein, the length of signal P is not less than the time span (t2-t3) of record or the length of the maximum that the system that reached allows.
B: referring to Fig. 6, the signal P of repeat its transmission is positioned at the back of Cyclic Prefix of current sign and next symbol foremost.Wherein, the length of signal P is not less than the time span (t4-t1) of record or the length of the maximum that the system that reached allows.
Top a and b, as can be seen, P has constituted new CP as a part and the former CP of Cyclic Prefix, so the length of Cyclic Prefix has increased from the figure of correspondence.
In addition, if the time window of multidiameter signal, the part of existing morning also has late part, and for example (t4-t3) among Fig. 4 then adopts a and b, simultaneously as the c among Fig. 4.
Because it is very slow that speed that channel latency changes and symbol period are compared, therefore, need in the transmission of each symbol, all not carry out the judgement of channel latency, and can be in a period of time, as between one or more time transmission range (TTI), need to judge whether the length of change Cyclic Prefix again.
In addition, the P information of above-mentioned increase can also be used to carrying the Useful Information that needs transmission, and like this, the information of P can be come out by demodulation in the Cyclic Prefix, improves the utilance of resource.As, signal P can be to need to send twice signal, for example control signal such as transformat indication.
When the recipient receives, at first cyclic prefix CP is removed, and then transformed to frequency domain, carry out filtering and equilibrium, transform to time-domain by IFFT again, carry out the demodulation of signal in frequency domain by FFT.Wherein, the Cyclic Prefix that removes and when not increasing circulating prefix-length, identical.Though promptly increased P and CP together as Cyclic Prefix, the recipient removes the CP that remains of Cyclic Prefix, and guarantees that still channel fading remains a circular convolution, and intersymbol does not disturb, and takies the orthogonality between signals of different frequency.
The signal that repeats by emission increases the method for circulating prefix-length above, has kept the time span of each symbol constant, and the length of the Cyclic Prefix that the recipient removes is constant.Therefore, can be in communication system at the size of each user's multipath expansion, whether decision increases the length of Cyclic Prefix, and the size of the length of the Cyclic Prefix that increases, make the length of Cyclic Prefix expand, do not influence the reception of a plurality of subscriber signals simultaneously greater than multipath.
The above only is preferred embodiment of the present invention, and is in order to restriction the present invention, within the spirit and principles in the present invention not all, any modification of being done, is equal to replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (5)
1. one kind reduces the data transmission method for uplink that multidiameter disturbs, to the signal after the modulation, produce a signal that does not comprise a symbol period of cyclic prefix CP by the transmitted pulse moulding, add cyclic prefix CP again, launch described CP and the described signal that does not comprise a symbol period of cyclic prefix CP, it is characterized in that this method may further comprise the steps:
Reception is from the announcement information of base station, described notification message is used to notify terminal to determine that in described base station the window of multidiameter signal compares delay that common Cyclic Prefix requires during evening, launch first signal at the afterbody in current sign cycle, and at the first identical signal of preceding surface launching of the afterbody Cyclic Prefix of next symbol, the time span of the maximum that the time span that the delay that to be the window that is not less than described multidiameter signal require than common Cyclic Prefix of the length of described first signal is late or the system that reaches allow; Or, described notification message is used to notify terminal to compare delay that common Cyclic Prefix requires early the time at the window of determining the multidiameter signal, back surface launching secondary signal at the Cyclic Prefix of current sign, in the identical secondary signal of the forefront of next symbol emission, the time span that the delay that to be the window that is not less than the multidiameter signal require than common Cyclic Prefix of the length of described secondary signal is Zao or reach the time span of the maximum of system's permission; Or, the part that described notification message is used to notify terminal to compare the window of delay evening that common Cyclic Prefix requires and described multidiameter signal in the part of the window of determining the multidiameter signal is compared delay that common Cyclic Prefix requires early the time, launch the 3rd signal at the afterbody in current sign cycle, and at the 3rd identical signal of preceding surface launching of the afterbody Cyclic Prefix of next symbol, the length of the maximum that the time span that the delay that to be the window that is not less than the multidiameter signal require than common Cyclic Prefix of the length of described the 3rd signal is late or the system that reaches allow, and at back surface launching the 4th signal of the Cyclic Prefix of current sign, at the 4th identical signal of the forefront of next symbol emission, the time span that the delay that to be the window that is not less than the multidiameter signal require than common Cyclic Prefix of the length of described the 4th signal is Zao or reach the length of the maximum of system's permission.
2. method according to claim 1 is characterized in that, described method also comprises:
Between one or more time transmission range, carry out the judgement of channel latency in (TTI).
3. method according to claim 1, it is characterized in that, the window of described multidiameter signal is: for the multipath signal that is received, and the signal time of measuring the time of the signal that receives the earliest and receiving the latest, the time difference of described two signals is as the window of described multidiameter signal.
4. method according to claim 1, it is characterized in that, further comprise: described first signal carries the available information that needs send, or described secondary signal carries and need the available information that sends, or described the 3rd signal and the 4th signal carry and need the available information that sends.
5. method according to claim 1 is characterized in that this method is applied to the transfer of data of single carrier.
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| CN200510076806XA CN1881968B (en) | 2005-06-15 | 2005-06-15 | Data transmission method for decreasing multipath delay interference |
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| CN200510076806XA CN1881968B (en) | 2005-06-15 | 2005-06-15 | Data transmission method for decreasing multipath delay interference |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP4033708A4 (en) * | 2019-11-01 | 2022-10-05 | Huawei Technologies Co., Ltd. | Symbol processing method and apparatus |
| EP3962009B1 (en) * | 2019-07-02 | 2024-03-20 | Huawei Technologies Co., Ltd. | Symbol processing method and device |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101383988A (en) * | 2007-09-05 | 2009-03-11 | 大唐移动通信设备有限公司 | Service multiplexing method and device for overlapped coverage in broadcast multicast system |
| US20170208575A1 (en) * | 2016-01-18 | 2017-07-20 | Qualcomm Incorporated | Low latency control overhead reduction |
| CN115189992A (en) * | 2021-04-02 | 2022-10-14 | 大唐移动通信设备有限公司 | Data processing method and device, network equipment and terminal equipment |
| WO2024012855A1 (en) * | 2022-07-13 | 2024-01-18 | Sony Group Corporation | A method for supporting beam switching, related first node and related second node |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1375969A (en) * | 2002-04-28 | 2002-10-23 | 武汉汉网高技术有限公司 | Data transmission equipment and method of OFDM communicaltion system |
| CN1559114A (en) * | 2001-11-28 | 2004-12-29 | ��ʿͨ��ʽ���� | Orthogonal frequency division multiplexing transmission method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1559114A (en) * | 2001-11-28 | 2004-12-29 | ��ʿͨ��ʽ���� | Orthogonal frequency division multiplexing transmission method |
| CN1375969A (en) * | 2002-04-28 | 2002-10-23 | 武汉汉网高技术有限公司 | Data transmission equipment and method of OFDM communicaltion system |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3962009B1 (en) * | 2019-07-02 | 2024-03-20 | Huawei Technologies Co., Ltd. | Symbol processing method and device |
| EP4033708A4 (en) * | 2019-11-01 | 2022-10-05 | Huawei Technologies Co., Ltd. | Symbol processing method and apparatus |
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