CN1972257A - Method and apparatus for implementing symmetry of channel in broadband orthogonal frequency division multiplexing system - Google Patents
Method and apparatus for implementing symmetry of channel in broadband orthogonal frequency division multiplexing system Download PDFInfo
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Abstract
This invention discloses one method to realize signal channel symmetric property based on wide band division, which comprises the following steps: communication point gets information transmission distribution molecule load wave channel estimation in receiving information; according to the values and through plug value computation point using sub load wave signal estimation value; computing signal channel estimation values for information send process.
Description
Technical field
The present invention relates to wideband OFDM (Orthogonal Frequency DivisionMultiplexing, the OFDM) system of time division duplex, relate in particular to method and the device of realizing channel symmetry in the wideband OFDM system.
Background technology
OFDM is the high speed transmission technology under a kind of wireless environment, given channel in the frequency domain is divided into many orthogonal sub-channels, on each subchannel, use a subcarrier to modulate, serial signal at a high speed is transformed to the signal of a plurality of parallel low rates and finishes the signal transmission by above-mentioned orthogonal sub-channels by string and conversion.Because each subcarrier is mutually orthogonal, make the frequency spectrum after the band spectrum modulation can be overlapped, thereby reduced the phase mutual interference between subcarrier, improved the availability of frequency spectrum simultaneously again.
Traditional TDD (Time Division Duplex, time division duplex) system adopts identical carrier wave to carry out the up-downgoing transmission, can estimate the channel of up direction, on down direction, utilize acquired channel estimation value to carry out some pretreatment operation, such as utilize the uplink channel estimation user side to information, on down direction, carry out wave beam forming then.Like this, traditional TDD system has the characteristics of up-downgoing channel symmetry.
In the wideband OFDM system of TDD, the user can use a plurality of subcarriers to carry out transfer of data, and promptly user profile can be mapped in parallel transmission on a plurality of subcarriers.As a rule, same user's up and downlink transfer can be mapped on the different subcarriers, if the channel estimation value that uplink obtained is directly applied to this user's downlink transfer, can influence reliability of information transmission.And in the prior art, the mapping of up-downgoing subcarrier is independently carried out respectively, and the subcarrier and the employed subcarrier of another direction that use on direction do not have correlation.
As seen, only under extremely accidental situation, when employed each subcarrier of up-downgoing transmission was identical, the wideband OFDM system of TDD just had the channel symmetry of up-downgoing.In other words, the wideband OFDM system of TDD can't be realized the up-downgoing channel symmetry in the prior art.
Summary of the invention
The present invention will solve is the problem that the wideband OFDM system of TDD in the prior art does not have the channel symmetry of up-downgoing.
The method that realizes channel symmetry in the wideband time division duplexing orthogonal frequency division multiplex OFDM system of the present invention may further comprise the steps:
Communication node acquired information when the information of reception transmits the channel estimation value of employed distributed sub-carrier;
According to the channel estimation value that is obtained, the channel estimation value of available subcarrier when sending information by the interpolation calculation communication node;
Communication node is by the channel estimation value that calculates, the preliminary treatment the when information of carrying out sends.
Alternatively, described channel estimation value by the interpolation calculation available subcarrier is specially: when the available subcarrier when sending is positioned within the subcarrier scope that obtains channel estimation value when receiving, by the channel estimation value that obtains is carried out to interpolate value, calculate the channel estimation value of available subcarrier when sending.
Alternatively, described channel estimation value by the interpolation calculation available subcarrier is specially: when the available subcarrier when sending is positioned at outside the subcarrier scope that obtains channel estimation value when receiving, by the channel estimation value that obtains is carried out to extrapolated value, calculate the channel estimation value of available subcarrier when sending.
Alternatively, described channel estimation value by the interpolation calculation available subcarrier is specially: when the available subcarrier when sending comprises the part that is positioned within the subcarrier scope that obtains channel estimation value when receiving with the part that is positioned at outside the described scope, the channel estimation value of available subcarrier when sending by the part of the channel estimation value that obtains being carried out to interpolate value, calculate being positioned within the described scope; The channel estimation value of available subcarrier when sending by the part of the channel estimation value that obtains being carried out to extrapolated value, calculate being positioned at outside the described scope.
Preferably, the subcarrier of described communication node information transmission is mapped as the local formula mapping of subcarrier.
Alternatively, described method also comprises: communication node sends information to the opposite end that communicates with after the preliminary treatment that information sends.
The invention provides a kind of device that is used for the realization channel symmetry of wideband time division duplexing orthogonal frequency division multiplex OFDM system, comprise receiving sub-carrier block, available subcarrier module, computing module and pretreatment module, wherein:
Receiving sub-carrier block is used for from reception information acquired information and transmits the channel estimation value of employed distributed sub-carrier;
Available subcarrier when the available subcarrier module is used for determining the information transmission;
Computing module is used for according to receiving the channel estimation value that sub-carrier block obtains, the channel estimation value of available subcarrier when going out the information transmission by interpolation calculation;
Pretreatment module is used for the channel estimation value that calculates according to computing module, the preliminary treatment the when information of carrying out sends.
The concrete grammar of the channel estimation value of available subcarrier was when alternatively, the computing module computing information sent:
When the available subcarrier when sending is positioned within the subcarrier scope that receives sub-carrier block acquisition channel estimation value, by the channel estimation value that obtains is carried out calculating the channel estimation value of described available subcarrier to interpolate value;
When the available subcarrier when sending is positioned at outside the subcarrier scope that receives sub-carrier block acquisition channel estimation value, by the channel estimation value that obtains is carried out calculating the channel estimation value of described available subcarrier to extrapolated value.
The present invention also provides a kind of application to realize the base station of channel symmetry method, comprises up receiving element, processing unit and descending transmitting element, wherein:
Up receiving element is used for receiving uplink information, and obtains the channel estimation value of the employed distributed sub-carrier of uplink information;
Processing unit is used for going out the channel estimation value of descending available subcarrier by interpolation calculation according to the uplink channel estimation value of up receiving element acquisition;
Descending transmitting element is used for the down channel estimated value that calculates according to processing unit, carries out the transmission of downlink information preliminary treatment and downlink information.
The present invention also provides a kind of application to realize the user terminal of channel symmetry method, comprises receiving element, arithmetic element and transmitting element, wherein:
Receiving element is used for the reception information and the channel estimation value of the employed distributed sub-carrier of acquired information;
Arithmetic element is used for going out the channel estimation value of transmitting element available subcarrier by interpolation calculation according to the channel estimation value of receiving element acquisition;
Transmitting element is used for the channel estimation value that calculates according to arithmetic element, carries out information preliminary treatment and information and sends.
The present invention utilizes the channel estimation value of distributed sub-carrier in the reception information, subcarrier channel estimation when drawing transmission by interpolation arithmetic, use it for the preliminary treatment that information sends, under the incomplete same situation of the employed subcarrier of TDD wideband OFDM system up-downgoing, realized the symmetry of channel.
Description of drawings
Fig. 1 is the local formula mapping schematic diagram of wideband OFDM system sub-carriers;
Fig. 2 is the distributed mapping schematic diagram of wideband OFDM system sub-carriers;
Fig. 3 is the flow chart of realization channel symmetry method of the present invention;
Subcarrier allocation exemplary plot when the available subcarrier when Fig. 4 is transmission is positioned within the subcarrier scope that obtains channel estimation value when receiving;
Subcarrier allocation exemplary plot when the available subcarrier when Fig. 5 is transmission is positioned at outside the subcarrier scope that obtains channel estimation value when receiving;
Available subcarrier when Fig. 6 is transmission partly is positioned within the subcarrier scope that obtains channel estimation value when receiving, the subcarrier allocation exemplary plot when part is positioned at outside the described scope;
Fig. 7 is the structure chart of the device of realization channel symmetry of the present invention.
Embodiment
In wideband OFDM system, carry out needing to set up before the message transmission mapping relations between transmission information and the subcarrier.Following two kinds of mapping modes are generally arranged: the local formula mapping of the first (LocalizedMapping), promptly use continuous a plurality of subcarriers; It two is distributed mapping (DistributdMapping), promptly uses discrete a plurality of subcarrier.If dot the subcarrier that is not used by this message transmission, and represent that with solid line this transmits employed subcarrier, then local formula is shone upon employed subcarrier as shown in Figure 1, and the employed subcarrier of distributed mapping as shown in Figure 2.
The major advantage of local formula mapping is to utilize the frequency selectivity of wideband OFDM system, the sub carrier group of selecting to be fit to its message transmission is transmitted, use link adaptation techniques simultaneously, allow transmitting terminal by changing transmission of Information code check or through-put power, adapt to the characteristic of channel on the different sub carrier.The major advantage of distributed mapping is to utilize the frequency diversity of wideband OFDM system, uses the discrete subcarrier that is distributed in the whole system bandwidth to carry out message transmission, and employed subcarrier disperses far more, and the frequency diversity effect of acquisition is obvious more.
Local formula mapping generally is used for the data traffic transmission under the low speed mobile environment, and this moment, the time-varying characteristics of channel were not obvious; And distributed sub-carrier generally is used for the transmission of data traffic transmission under the high-speed mobile environment and control information, feedback information, adapting to the tangible time-varying characteristics of high-speed case lower channel, and by frequency diversity for control information with feedback information provides fast, transmission reliably.
Under local formula mapping mode, the user uses a plurality of continuous sub-carriers to carry out message transmission.Though symmetry according to TDD system up-downgoing channel, the identical subcarrier of up in theory and descending use carries out message transmission and can obtain better transmission performance, but because the asymmetry characteristics of up-downgoing business, it is infeasible basically that user's uplink is used identical subcarrier with downlink transfer.
For distributed mapping, subcarrier is distributed in the frequency band discretely, shared frequency band broad.Carry out message transmission if use distributed mapping on direction of up-downgoing, the communication node of reception information just can be by carrying out channel estimating to received signal, obtain the characteristic of channel on the broad frequency band, as long as the employed frequency band of transmission is positioned near the bandwidth range that obtains channel estimation value on the another one direction, just can utilize the channel estimation value of acquisition to communicate the transmission pretreatment operation of node, carry out the message transmission on the another one direction, thereby realize the symmetry of up-downgoing channel.
Figure 3 shows that the flow chart of realization channel symmetry method of the present invention.At step S010, communication node receives the information that the opposite end that communicates with sends in subcarrier distributed mapping mode.
At step S020, the original position a of the employed subcarrier of communication node recorder information and final position b; In the information of reception, communication node also obtains the channel estimation value of the employed a plurality of distributed sub-carriers of reception information.
The start-stop position a of record subcarrier and b are the scopes [a, b] in order to indicate the employed distributed sub-carrier of reception information.Be without loss of generality, can be with subcarrier according to the order number consecutively from the low frequency to the high frequency, then original position a is the numbering of the minimum subcarrier of the employed distributed sub-carrier medium frequency of reception information, final position b is the numbering of the highest subcarrier of frequency.
Communication node adopts method of the prior art can obtain the channel estimation value of distributed sub-carrier from reception information.
At step S030, the subcarrier that can use when communication node is determined transmission information.
At step S040, when judge sending can with subcarrier whether all be positioned within [a, b] scope, if, execution in step S050; If not, execution in step S060.
At step S050, utilize the channel estimation value of a plurality of distributed sub-carriers in [a, the b] scope that obtains, by method, calculate the channel estimation value of available subcarrier when sending to interpolate value, change step S090.
At step S060, when judge sending can with subcarrier whether all be positioned at outside [a, b] scope, if, execution in step S070; If not, execution in step S080.
At step S070, utilize the channel estimation value of a plurality of distributed sub-carriers in [a, the b] scope that obtains, by method, calculate the channel estimation value of available subcarrier when sending to extrapolated value, change step S090.
At step S080, during transmission can with subcarrier comprise the part that is positioned within [a, b] scope and be positioned at part outside [a, b] scope.Utilize the channel estimation value of a plurality of distributed sub-carriers in [a, the b] scope that obtains, the channel estimation value of available subcarrier when calculating the part transmission that is positioned within [a, b] scope by method to interpolate value; The channel estimation value of available subcarrier when calculating the part transmission that is positioned at outside [a, b] scope by method to extrapolated value.
From step S040 to S080, the channel estimation value of a plurality of distributed sub-carriers in [a, b] scope that the communication node utilization obtains when receiving information, the channel estimation value of available subcarrier when drawing transmission by interpolation algorithm.By the next characteristic of channel of interpolation algorithm, estimate the characteristic of channel of other unknown subcarriers comparatively exactly among the present invention, be provided at the basis of realizing channel symmetry on the different subcarrier of up-downgoing according to some known subcarrier.
The equipment and the environment that adopt which kind of interpolation algorithm specifically to use according to the present invention are determined, for example adopt once linear interpolation algorithm, quadratic interpolation algorithm etc.The existing in the prior art multiple implementation of interpolation algorithm repeats no more herein.
At step S090, the channel estimation value of communication node available subcarrier during by the transmission that calculates carries out the preliminary treatment that information sends.
Carry out the subcarrier mapping according to the channel symmetry in this step, both can adopt local formula carrier wave mapping mode, also can adopt the distributed sub-carrier mapping mode.The present invention recommends to adopt local formula carrier wave mapping mode, because employed subcarrier was positioned at when receiving employed subcarrier scope or employed subcarrier scope during as much as possible near reception when communication node was sent, these subcarrier channel estimation of utilizing interpolation algorithm to obtain have higher accuracy, thereby realize channel symmetry better.
In addition, according to the channel estimation value on each subcarrier that obtains, the pretreatment operation that the information of carrying out sends comprises multiple mode, such as carrying out link circuit self-adapting, wave beam forming etc.When carrying out wave beam forming, communication node can be by the weights of the channel estimation value compute beam figuration on each subcarrier that obtains.A kind of weight calculation method of typical wave beam forming is that the win the confidence conjugation of estimated value gets final product.When carrying out wave beam forming, communication node uses the weights that calculate, and multiply by the information data that needs transmission, obtains pretreated information data.
At step S100, communication node sends information to the opposite end, realizes the channel symmetry of up-downgoing.
Said method of the present invention can be used for carrying out downlink transfer according to the channel estimation value of uplink, also can be used for carrying out uplink according to the channel estimation value of downlink transfer.
How below illustrate communication node according to the employed subcarrier channel estimation of receive direction, determine the employed subcarrier of sending direction.After pressing subcarrier from the low frequency to the high frequency sorting, the numbering of the employed distributed sub-carrier of communication node receive direction is respectively 15,20,25,30,35,40,45,50,55 and 60, and then the start-stop position of this subcarrier is respectively a=15, b=60.
Figure 4 shows that communication node sending direction can with subcarrier be positioned at situation within [a, b] scope.At this moment, can utilize the channel estimation value of 10 distributed sub-carriers within [a, the b] scope that obtains from receive direction, obtain channel estimation value at the available subcarrier of sending direction by inside interpolation algorithm.According to sending direction subcarrier channel estimation result of calculation, communication node carries out preliminary treatment to transmission information, and uses the local formula mapping mode of subcarrier, and the information of carrying out sends on 45 to 56 the subcarrier being numbered.
Figure 5 shows that communication node sending direction can with subcarrier be positioned at situation outside [a, b] scope.At this moment, can utilize the channel estimation value of 10 distributed sub-carriers within [a, the b] scope that obtains from receive direction, obtain channel estimation value at the available subcarrier of sending direction by outside interpolation algorithm.According to sending direction subcarrier channel estimation result of calculation, communication node carries out preliminary treatment to transmission information, and uses the local formula mapping mode of subcarrier, and the information of carrying out sends on 61 to 72 the subcarrier being numbered.
Figure 6 shows that communication node sending direction can with subcarrier partly be positioned within [a, b] scope, part is positioned at situation outside [a, b] scope.At this moment, can utilize [a that obtains from receive direction, b] the channel estimation value of 10 distributed sub-carriers within the scope, obtain to be positioned at [a by inside interpolation algorithm at sending direction, b] the channel estimation value of available subcarrier in the scope, obtain to be positioned at the channel estimation value of [a, b] extraneous available subcarrier at sending direction by outside interpolation algorithm.According to sending direction subcarrier channel estimation result of calculation, communication node carries out preliminary treatment to transmission information, and the distributed mapping mode of use subcarrier, be respectively in numbering that the information of carrying out sends on 6,10,14,18,22,26,30,34,38 and 42 the subcarrier, its sub-carriers 6,10,14 is positioned at [a, b] outside the scope, subcarrier 18,22,26,30,34,38 and 42 is positioned within [a, b] scope.
Figure 7 shows that the device that is used for the realization channel symmetry of wideband OFDM system of the present invention.Computing module 720 is connected with pretreatment module 740 with reception sub-carrier block 710, available subcarrier module 730 respectively, and available subcarrier module 730 is connected with pretreatment module 740.
Receive sub-carrier block 710 obtains the employed distributed sub-carrier of this message transmission of receive direction from reception information channel estimation value, use during for the channel estimation value of computing module 720 available subcarrier when calculating next transmission.
Available subcarrier when available subcarrier module 730 is used for determining the information transmission.
Computing module 720 is read the channel estimation value of the distributed sub-carrier of receive direction acquisition from receiving sub-carrier block 710, determines the scope of the employed distributed sub-carrier of receive direction; According to the available subcarrier of the sending direction that from available subcarrier module 730, obtains, the channel estimation value of available subcarrier when going out next information and send by interpolation calculation.When the available subcarrier of sending direction is positioned within the employed subcarrier scope of receive direction, the channel estimation value that obtains is carried out to interpolate value, calculate the channel estimation value of sending direction available subcarrier in this scope; When the available subcarrier of sending direction is positioned at outside the employed subcarrier scope of receive direction, the channel estimation value that obtains is carried out to extrapolated value, calculate the channel estimation value of the outer sending direction available subcarrier of this scope.
The channel estimation value that pretreatment module 740 calculates according to computing module 720, in conjunction with the available subcarrier of available subcarrier module 730 outputs, the preliminary treatment the when information of carrying out sends.
The method of realization channel symmetry of the present invention can be used for the up-downgoing transmission between base station and the user terminal, also can be used for the message transmission between the user terminal.
To the base station of the method for using realization channel symmetry of the present invention, can the part that relate to the subcarrier mapping be described with up receiving element, processing unit and descending transmitting element.Wherein up receiving element receives the user profile of uplink, and obtains the channel estimation value that uplink information transmits employed distributed sub-carrier; Processing unit goes out the channel estimation value of descending available subcarrier according to the uplink channel estimation value that up receiving element obtains by interpolation calculation; Descending transmitting element carries out the transmission of downlink information preliminary treatment and downlink information according to the down channel estimated value that processing unit calculates.
To using the user terminal of sub-carrier mapping method of the present invention, can the part that relate to the subcarrier mapping be described with receiving element, arithmetic element and transmitting element.Wherein receiving element receives and is sent to the information of this user terminal, and obtains the channel estimation value of the employed distributed sub-carrier of this message transmission; Arithmetic element goes out the channel estimation value of transmitting element available subcarrier according to the channel estimation value that receiving element obtains by interpolation calculation; Transmitting element sends information preliminary treatment and information and sends according to the channel estimation value that arithmetic element calculates.
The distributed sub-carrier mapping mode can provide the channel estimation value of broad frequency band scope in the wideband OFDM system of time division duplex, the present invention comes the sub-carrier channels of another transmission direction is estimated comparatively accurately by utilizing a plurality of subcarrier channel estimation, thereby realized the symmetry of up-downgoing channel.
Above-described embodiment of the present invention does not constitute the qualification to protection range of the present invention.Any any modification of being done within the spirit and principles in the present invention, be equal to and replace and improvement etc., all should be included within the claim protection range of the present invention.
Claims (10)
1. realize the method for channel symmetry in the wideband time division duplexing orthogonal frequency division multiplex OFDM system, it is characterized in that, may further comprise the steps:
Communication node acquired information when the information of reception transmits the channel estimation value of employed distributed sub-carrier;
According to the channel estimation value that is obtained, the channel estimation value of available subcarrier when sending information by the interpolation calculation communication node;
Communication node is by the channel estimation value that calculates, the preliminary treatment the when information of carrying out sends.
2. realize the method for channel symmetry according to claim 1 in the wideband time division duplexing ofdm system, it is characterized in that, described channel estimation value by the interpolation calculation available subcarrier is specially: when the available subcarrier when sending is positioned within the subcarrier scope that obtains channel estimation value when receiving, by the channel estimation value that obtains is carried out to interpolate value, calculate the channel estimation value of available subcarrier when sending.
3. realize the method for channel symmetry according to claim 1 in the wideband time division duplexing ofdm system, it is characterized in that, described channel estimation value by the interpolation calculation available subcarrier is specially: when the available subcarrier when sending is positioned at outside the subcarrier scope that obtains channel estimation value when receiving, by the channel estimation value that obtains is carried out to extrapolated value, calculate the channel estimation value of available subcarrier when sending.
4. realize the method for channel symmetry according to claim 1 in the wideband time division duplexing ofdm system, it is characterized in that, described channel estimation value by the interpolation calculation available subcarrier is specially: when the available subcarrier when sending comprises the part that is positioned within the subcarrier scope that obtains channel estimation value when receiving with the part that is positioned at outside the described scope, the channel estimation value of available subcarrier when sending by the part of the channel estimation value that obtains being carried out to interpolate value, calculate being positioned within the described scope; The channel estimation value of available subcarrier when sending by the part of the channel estimation value that obtains being carried out to extrapolated value, calculate being positioned at outside the described scope.
5. as realizing the method for channel symmetry in the wideband time division duplexing ofdm system as described in any one of the claim 2 to 4, it is characterized in that: the subcarrier that described communication node information sends is mapped as the local formula mapping of subcarrier.
6. as realizing the method for channel symmetry in the wideband time division duplexing ofdm system as described in the claim 5, it is characterized in that described method also comprises: communication node sends information to the opposite end that communicates with after the preliminary treatment that information sends.
7. a device that is used for the realization channel symmetry of wideband time division duplexing orthogonal frequency division multiplex OFDM system is characterized in that, comprise receiving sub-carrier block, available subcarrier module, computing module and pretreatment module, wherein:
Receiving sub-carrier block is used for from reception information acquired information and transmits the channel estimation value of employed distributed sub-carrier;
Available subcarrier when the available subcarrier module is used for determining the information transmission;
Computing module is used for according to receiving the channel estimation value that sub-carrier block obtains, the channel estimation value of available subcarrier when going out the information transmission by interpolation calculation;
Pretreatment module is used for the channel estimation value that calculates according to computing module, the preliminary treatment the when information of carrying out sends.
8. as being used for the device of the realization channel symmetry of wideband time division duplexing ofdm system as described in the claim 7, it is characterized in that the concrete grammar of the channel estimation value of available subcarrier was when the computing module computing information sent:
When the available subcarrier when sending is positioned within the subcarrier scope that receives sub-carrier block acquisition channel estimation value, by the channel estimation value that obtains is carried out calculating the channel estimation value of described available subcarrier to interpolate value;
When the available subcarrier when sending is positioned at outside the subcarrier scope that receives sub-carrier block acquisition channel estimation value, by the channel estimation value that obtains is carried out calculating the channel estimation value of described available subcarrier to extrapolated value.
9. an application rights requires the base station of 1 described method, it is characterized in that, comprises up receiving element, processing unit and descending transmitting element, wherein:
Up receiving element is used for receiving uplink information, and obtains the channel estimation value of the employed distributed sub-carrier of uplink information;
Processing unit is used for going out the channel estimation value of descending available subcarrier by interpolation calculation according to the uplink channel estimation value of up receiving element acquisition;
Descending transmitting element is used for the down channel estimated value that calculates according to processing unit, carries out the transmission of downlink information preliminary treatment and downlink information.
10. an application rights requires the user terminal of 1 described method, it is characterized in that, comprises receiving element, arithmetic element and transmitting element, wherein:
Receiving element is used for the reception information and the channel estimation value of the employed distributed sub-carrier of acquired information;
Arithmetic element is used for going out the channel estimation value of transmitting element available subcarrier by interpolation calculation according to the channel estimation value of receiving element acquisition;
Transmitting element is used for the channel estimation value that calculates according to arithmetic element, carries out information preliminary treatment and information and sends.
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Cited By (4)
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| CN101868951A (en) * | 2007-11-21 | 2010-10-20 | 阿瓦雷公司 | The stable low-power mode that is used for multicarrier transceivers |
| CN102130754A (en) * | 2011-03-11 | 2011-07-20 | 中兴通讯股份有限公司 | Method and system for realizing cooperative precoding |
| WO2017049486A1 (en) * | 2015-09-23 | 2017-03-30 | 华为技术有限公司 | Terminal device, network device, method for transmitting uplink reference signal and method for receiving same |
| CN107819497A (en) * | 2016-09-12 | 2018-03-20 | 中兴通讯股份有限公司 | Space division multiplexing method, device and base station based on carrier aggregation |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT1295863B1 (en) * | 1997-10-22 | 1999-05-28 | Telital Spa | METHOD AND APPARATUS FOR TRANSMISSION AND RECEPTION OF DIGITAL SIGNALS AND ESTIMATION OF COMMUNICATION CHANNELS |
| CN100336325C (en) * | 2002-06-19 | 2007-09-05 | 上海贝尔有限公司 | Channel estimation method of Rake receiver |
| CN1300962C (en) * | 2002-12-31 | 2007-02-14 | 上海贝尔阿尔卡特股份有限公司 | Method and device of equalized fast fading channel in orthogonal frequency dirision multiplex system |
| CN1221096C (en) * | 2003-03-08 | 2005-09-28 | 华中科技大学 | Channel estimation method for orthogonal frequency-division multiplexing communication system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101868951A (en) * | 2007-11-21 | 2010-10-20 | 阿瓦雷公司 | The stable low-power mode that is used for multicarrier transceivers |
| US8837610B2 (en) | 2007-11-21 | 2014-09-16 | Tq Delta, Llc | Stable low power mode for multicarrier transceivers |
| CN102130754A (en) * | 2011-03-11 | 2011-07-20 | 中兴通讯股份有限公司 | Method and system for realizing cooperative precoding |
| WO2012122810A1 (en) * | 2011-03-11 | 2012-09-20 | 中兴通讯股份有限公司 | Method and system for implementing cooperative precoding |
| CN102130754B (en) * | 2011-03-11 | 2017-06-13 | 中兴通讯股份有限公司 | A kind of method and system for realizing cooperateing with precoding |
| WO2017049486A1 (en) * | 2015-09-23 | 2017-03-30 | 华为技术有限公司 | Terminal device, network device, method for transmitting uplink reference signal and method for receiving same |
| US10560947B2 (en) | 2015-09-23 | 2020-02-11 | Huawei Technologies Co., Ltd. | Terminal device, network device, uplink reference signal sending method, and uplink reference signal receiving method |
| CN107819497A (en) * | 2016-09-12 | 2018-03-20 | 中兴通讯股份有限公司 | Space division multiplexing method, device and base station based on carrier aggregation |
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| CN1972257B (en) | 2011-04-13 |
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