US20150094108A1 - Receiver and a method for mobile communications - Google Patents
Receiver and a method for mobile communications Download PDFInfo
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- US20150094108A1 US20150094108A1 US14/562,694 US201414562694A US2015094108A1 US 20150094108 A1 US20150094108 A1 US 20150094108A1 US 201414562694 A US201414562694 A US 201414562694A US 2015094108 A1 US2015094108 A1 US 2015094108A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
- H04L27/2662—Symbol synchronisation
- H04L27/2665—Fine synchronisation, e.g. by positioning the FFT window
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/003—Arrangements for allocating sub-channels of the transmission path
- H04L5/0032—Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W56/00—Synchronisation arrangements
- H04W56/001—Synchronization between nodes
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
- H04L25/0204—Channel estimation of multiple channels
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
- H04L25/0224—Channel estimation using sounding signals
- H04L25/0228—Channel estimation using sounding signals with direct estimation from sounding signals
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- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Mobile Radio Communication Systems (AREA)
Abstract
In a method and a mobile communications receiver for processing signals from a first cell and a second cell a timing of the signal from the first cell and the second cell is obtained. A timing difference (δ) between the timings of signals from the first and the second cell is determined and based on that a timing (κ) for a window for discrete Fourier transform, DFT, processing is adjusted. DFT processing of the signals using the timing (κ) of the DFT window is then performed.
Description
- The present invention relates to a method and a receiver for processing a signal in a mobile communications system.
- Recently, an increased demand for high data rates in mobile communications has been seen, and this trend will most likely continue in the coming years.
- In order to meet this demand, new transmission techniques have been developed. In the forthcoming evolution of present mobile cellular standards like GSM and Wideband Code Division Multiple Access (WCDMA), Orthogonal Frequency Multiple Access (OFDM) will be used for transmission. OFDM promises higher data rates and a more efficient usage of limited bandwidth resources than the presently employed techniques.
- Furthermore, in order to have a smooth migration from the existing cellular systems to a new high capacity and high data rate system in existing radio spectrum, such a new system has to be able to operate in a flexible bandwidth. A proposal for such a new flexible cellular system is 3G Long Term Evolution (3G LTE) that can be seen as an evolution of the 3G WCDMA standard. This system will use OFDM as multiple access technique (called OFDMA) in the downlink and will be able to operate on bandwidths ranging from 1.4 MHz to 20 MHz. Furthermore, data rates up to 100 Mb/s will be supported for the largest bandwidth, and such data rates will be possible to reach using MIMO (Multiple-Input-Multiple Output) schemes in the down-link.
- In such a system, and in a situation where a mobile device is surrounded by a number of cells, problems relating to strong inter-cell interference (ICI) may occur. In order to optimize the throughput also in such a situation, the mobile device needs to implement methods for handling such inter-cell interference.
- A method of processing a signal in a mobile communications system is presented, wherein the inter-cell interference is mitigated in a receiver by adjusting the position of a window for discrete Fourier transform, DFT, processing based on a timing difference between a first cell and a second cell. In this way a possible joint channel estimate procedure and, in turn, the quality of the demodulated symbols are improved.
- Specifically, according to embodiments of the invention, in a method, in a mobile communications receiver, of processing signals received from a first cell and a second cell, a timing of the signal from the first cell is obtained, and a timing of the signal from the second cell is obtained. A timing difference between the timings of the signals from the first and the second cell is determined and a timing for a window for DFT, processing is adjusted based on the timing difference. The signals are then DFT processed using the adjusted timing of the DFT window.
- The invention will be described more fully below with reference to the drawings, in which:
-
FIG. 1 is a schematic view of a receiver arrangement. -
FIG. 2 shows part of a mobile communications system. -
FIG. 3 illustrates received signals from two cells. -
FIG. 4 shows power delay profiles for two received signals. -
FIG. 5 illustrates received multipath signals from two cells. -
FIGS. 6A and 6B illustrates the effective Signal to Noise Ration (SNR) as a function of DFT window placement for two different timing differences. -
FIG. 7 shows parts of a receiver according to embodiments of the invention. -
FIG. 8 shows a flow diagram of embodiments of the invention. - To facilitate an understanding of exemplifying embodiments of the invention, many aspects are described in terms of sequences of actions that can be performed by elements of a computer system. For example, it will be recognized that in each of the embodiments, the various actions can be performed by specialized circuits or circuitry (e.g., discrete logic gates interconnected to perform a specialized function), by program instructions being executed by one or more processors, or by a combination of both.
- In
FIG. 1 areceiver 10 is shown which receives signals via areceiver antenna 12. In thereceiver 10, the signals received by the antenna are first processed by a radio front end (RF)unit 14, then by a baseband (BB)unit 16 and then possibly by someadditional unit 18. - In
FIG. 2 , amobile device 20 is connected to a first cell 22 (serving cell) of a radio base station 24 (also called Node B). The mobile device comprises areceiver 10 ofFIG. 1 . The mobile device is surrounded by a number of neighboringcells 26, associated with the same or another base station. In each cell, pilot symbols are transmitted to be used by mobile devices when obtaining channel estimates for that cell. However, the transmission of pilots from the neighboring cell(s) also causes interference when themobile device 20 is obtaining channel estimates for the servingcell 22. To improve the situation, joint channel estimation may be used, where the receiver calculates channel estimates based on both the pilot symbols from the serving cell and for one or more neighboring cells. In this disclosure, only one neighboring cell is used in the exemplifying embodiments, but extension to more than one neighboring cell is straightforward. - When a receiver calculates channel estimates in an OFDM based system, (or a system employing any access technique with DFT processing in the receiver, such as single-carrier frequency division multiple access, SC-FDMA) a timing κ for a window for DFT processing needs to be set. In
FIG. 3 , u(t) denotes the signal from the serving cell and v(t) denotes the signal from the neighboring cell. CP denotes the cyclic prefix part of the signals. The neighboring cell signal v(t) is delayed δ samples (δ may be negative or positive) compared to the serving cell signal u(t). - It may be noted that v(t) may also be a signal from a second serving cell. This may be the case when COordinated Multipoint transmission (COMP) is used.
- A first option is to place the DFT window such that the start of the window is somewhere in the cyclic prefix of the serving cell signal u(t). This would be the timing used when obtaining channel estimates only for the serving cell.
- However, when the mobile device calculates improved channel estimates using a joint channel estimation approach with a neighboring cell with typically other timing than the serving cell—in this case the timing difference is δ—relying placement of the DFT window solely on the serving cell may lead to unnecessary Inter Signal Interference (ISI), and, hence, lower quality channel estimates.
- According to embodiments of the inventions, the timing difference δ between the serving cell signal u(t) and the neighboring cell signal v(t) is taken into account for determining the timing of the DFT window. This may be done in different ways. One option is to place the DFT window so that the start of the window is at δ/2.
- Another option is to take the signal power of the serving cell and the neighboring cell into account and use the ratio between the power of the neighboring cell and the serving cell when determining the timing for the window, according to:
-
- wherein κ is the timing of the DFT window, PNBC is the signal power of the neighboring cell, and PSC is the signal power of the serving cell. The signal power of the serving cell and the neighboring cell may e.g. be obtained from Reference Signal Received Power (RSRP) measurements.
- A weighting factor α, 0≦α≦1, possibly predetermined in simulations, may be included according to:
-
- These two expressions both assume a single tap channel, but it would also be possible to extend the expressions to a multi-tap channel. In that case a power delay profile is determined for the signals, such as is illustrated in
FIG. 4 . The PDP comprises a number of channel taps h0, h1, g0 and g1. h0 and h1 are associated with the signal from the serving cell and g0 and g1 are associated with the signal from the neighboring cell. Each channel tap has a respective tap power, which is symbolized by the height of the taps inFIG. 4 . - In
FIG. 5 the four different channel taps are illustrated as well, and here n0, n1, n2 and n3 are the number of samples in the DFT window that do not belong to the symbol that is being estimated. - A timing of the window can also be calculated by minimizing the sum of the tap powers for the channels taps h0, h1, g0 and g1, multiplied by the respective number of excess samples, n0, n1, n2 and n3, outside the symbol that is estimated. In
FIG. 5 this would be equal to minimizing the dotted areas. The width of these areas symbolizes the number of samples which do not belong to the symbols that are being estimated. The height of each dotted area symbolizes the channel tap power. Thus, in the illustrated example we want to choose a timing for the window, i.e. a value of κ, that minimizes -
n 0 ·|h 0|2 +n 1 ·|h 1|2 +n 2 ·|g 0|2 +n 3 ·|g 1|2, - wherein the straight brackets means the absolute value.
- Another way of expressing this would be by starting with the expression for the received signal after the DFT processing. Note that the following discussion, for the sake of simplicity, has been limited to a one tap channel, but, again, extension to a multitap channel is straightforward.
- The signal after DFT can be described by:
-
y(t)=H(t)u(t)+G(t)v(t)+{tilde over (H)}(t)ũ(t)+{tilde over (G)}(t){tilde over (v)}(t)+n(t) - Here H(t) is the channel for the serving cell and G(t) the channel for the neighboring cell. {tilde over (H)}(t)ũ(t) and {tilde over (G)}(t){tilde over (v)}(t) model the ICI and the ISI, i.e. these two terms correspond to the samples which are inside the DFT window, but outside the symbol that is being estimated, this in turn corresponding to what is shown as the dotted areas in
FIG. 5 . n(t) is the background noise. - For the serving cell signal u(t) the number of samples Nu being outside the symbol of interest but still in the DFT window is:
-
- For the neighboring cell signal v the number of samples Nv that are outside the symbol of interest but still in the DFT window is:
-
- In these expressions, Ncp is the number of samples in the cyclic prefix of the symbol. Finally, the variance of the disturbance etot of the joint channel estimate due to ICI, ISI and background noise can be calculated as
-
- Here NDFT is the number of samples in the DFT window, or in other words, the length of the DFT window. The variance of the background noise is σ2. By minimizing this expression a timing κ for the DFT window can be found.
- The effective SNR is equal to the signal power V(H(t)u(t)) divided by the variance of the disturbance etot. In
FIGS. 6A and 6B the effective SNR is shown for different timings κ of the window for DFT processing.FIG. 6A shows the case where the timing difference δ between the serving cell and the neighboring cell is smaller than the cyclic prefix andFIG. 6B shows the case where δ is larger than the cyclic prefix. By using superposition it is possible to also calculate a position for the DFT window for other types of dispersive channels. - An alternative way of describing this is that the variance of the channel estimate is minimized for κ.
- As a further option for determining how the timing of the DFT window should be adjusted, the variance of the error in the demodulated signal, can be minimized for κ.
- The demodulated signal is equal to the DFT processed signal y(t) divided by an estimate of the channel received from a (joint) channel estimation unit. Since both y(t) and the channel estimate depend on κ and δ, the variance of the demodulated signal will also be dependent on κ and δ. A value of κ may be then be found by minimizing the variance of the demodulated signal for κ.
- In
FIG. 7 relevant parts of thebaseband unit 16 of thereceiver 10 are shown. Acell search unit 28 detects the neighboring cell and determines the timing and the power delay profile of the serving cell and the neighboring cell from the received signals. Acontrol unit 30 determines the timing difference δ based on the timings of the serving cell and the neighboring cell, and then determines an adjustment of the timing κ for the window for DFT processing based on at least the timing difference δ according to any of the methods discussed above. ADFT unit 32 removes the cyclic prefix and places the window for DFT processing according to the determined timing κ and then DFT processes the received signal. In this context, it may be noted that the DFT unit often is implemented as a unit performing fast Fourier transform (FFT) processing. - A joint
channel estimation unit 34 may then calculate a joint channel estimate using the DFT processed signal and information regarding pilot symbols and their frequency location conveyed through the cell id for the serving cell and the neighboring cell which is received from thecell search unit 28. Ademodulation unit 36 then demodulates the signal. - In some embodiments of the invention, the joint channel estimation is only performed in case the control unit determines that the ratio of the signal power of the neighboring cell to the serving cell is above a predetermined threshold, e.g. if the neighboring cell is less than 10 dB weaker than the serving cell.
- Additionally, the time alignment between the serving cell and the neighboring cell, i.e. δ, may be used to determine if joint channel estimation is to be performed. E.g. if δ is larger than 3-5 times the length of the cyclic prefix, channel estimation may be based only on the serving cell.
- In
FIG. 8 , a method according to embodiments of the invention is illustrated. Instep 38, a timing is obtained for a first and a second cell. In the above discussed example, the first cell is a serving cell and the second cell is a neighboring cell. Instep 40 the timing κ of the window for DFT processing is determined based at least on the timing difference δ between the timings of the first cell and the second cell. Instep 42 DFT processing is performed using the determined timing κ of the DFT window. - It may be noted that the above discussion is related to a single transmitter/single receiver antenna case, but extension to several transmitter and/or receiver antennas would be straightforward.
- Although reference is here made to a receiver in a mobile device, such as a mobile terminal or a user equipment (UE), it should be noted that the methods and apparatus described may be used at any telecommunications receiver, i.e. in a mobile station or a base station, and the transmission may be uplink or downlink.
- Thus, the embodiments disclosed herein are merely illustrative and should not be considered restrictive in any way. The scope of the invention is given by the appended claims, rather than the preceding description, and all variations which fall within the range of the claims are intended to be embraced therein.
Claims (28)
1. A method, in a mobile communications receiver, of processing signals from a first cell and a second cell, the method comprising:
obtaining a timing of the signal from the first cell;
obtaining a timing of the signal from the second cell;
determining a timing difference between the timings of signals from the first and the second cell;
adjusting a timing for a window for discrete Fourier transform, DFT, processing based on the timing difference;
performing DFT processing of the signals using the timing of the DFT window;
obtaining a power delay profile of the first cell and a power delay profile of the second cell, the power delay profiles comprising a number of channel taps having respective tap powers; and
adjusting the timing of the window by minimizing the sum, over all channel taps, of the respective tap power multiplied with a respective number of samples that are covered by the FFT window but are outside a symbol of interest.
2. (canceled)
3. (canceled)
4. The method of claim 1 , further comprising determining a joint channel estimate associated with the first and the second cell.
5. The method of claim 4 , further comprising:
determining a joint channel estimate associated with the first and the second cell, only if a ratio between a signal power of the second cell and a signal power of the first cell is above a predetermined signal power threshold.
6. The method of claim 4 , further comprising:
determining a joint channel estimate associated with the first and the second cell only if the timing difference is below a predetermined timing threshold.
7. The method of claim 4 , further comprising:
adjusting the timing of the window so that a variance of the joint channel estimate is minimized.
8. The method of claim 1 , further comprising:
demodulating the DFT processed signal to produce a demodulated signal; and
adjusting the timing of the window so that a variance of an error of the demodulated signal is minimized.
9. A mobile communications receiver, comprising:
a cell search unit configured to obtain a timing of a signal from a first cell and a timing of signal from a second cell;
a control unit configured to determine a timing difference between the timing of the signal from the first cell and the timing of the signal from the second cell and to adjust a timing for a window for discrete Fourier transform, DFT, processing based on the timing difference; and
an FFT unit adapted to DFT process the signals using the timing of the DFT window,
wherein the cell search is further adapted to obtain a power delay profile of the first cell and a power delay profile of the second cell, the power delay profiles comprising a number of channel taps having respective tap powers, and
the control unit is further adapted to adjust the timing of the window by minimizing the sum, over all channel taps, of the respective tap power multiplied with a respective number of samples that are covered by the FFT window but are outside a symbol being estimated.
10. (canceled)
11. (canceled)
12. The receiver of claim 9 , further comprising a joint channel estimation unit configured to determine a joint channel estimate associated with the first and the second cell.
13. The receiver of claim 12 , wherein the joint channel estimation unit is configured to determine a joint channel estimate associated with the first and the second cell, only if a ratio between a signal power of the second cell and a signal power of the first cell is above a predetermined signal power threshold.
14. The receiver of claim 12 , wherein the joint channel estimation unit is configured to determine a joint channel estimate associated with the first and the second cell, respectively, only if the timing difference is below a predetermined timing threshold.
15. The method of claim 12 , wherein the control unit is adapted to adjust the timing of the window so that a variance of the joint channel estimate is minimized.
16. The method of claim 9 , wherein the control unit is adapted to adjust the timing of the window so that a variance of an error of the demodulated signal is minimized.
17. A method, in a mobile communications receiver, of processing signals from a first cell and a second cell, the method comprising:
obtaining a timing of the signal from the first cell;
obtaining a timing of the signal from the second cell;
determining a timing difference between the timings of signals from the first and the second cell;
adjusting a timing for a window for discrete Fourier transform (DFT) processing based on the timing difference;
performing DFT processing of the signals using the timing of the DFT window;
demodulating the DFT processed signal to produce a demodulated signal; and
adjusting the timing of the window so that a variance of an error of the demodulated signal is minimized.
18. The method of claim 17 , further comprising determining a joint channel estimate associated with the first and the second cell.
19. The method of claim 17 , further comprising
determining a ratio between a signal power of the second cell and a signal power of the first cell; and
adjusting the timing of the window based on the ratio.
20. The method of claim 19 , further comprising determining a joint channel estimate associated with the first and the second cell.
21. The method of claim 17 , further comprising
obtaining a power delay profile of the first cell and a power delay profile of the second cell, the power delay profiles comprising a number of channel taps having respective tap powers; and
adjusting the timing of the window by minimizing the sum, over all channel taps, of the respective tap power multiplied with a respective number of samples that are covered by the FFT window but are outside a symbol of interest.
22. The method of claim 21 , further comprising determining a joint channel estimate associated with the first and the second cell.
23. A mobile communications receiver, comprising
a cell search unit configured to obtain a timing of a signal from a first cell and a timing of signal from a second cell;
a control unit configured to determine a timing difference between the timing of the signal from the first cell and the timing of the signal from the second cell and to adjust a timing for a window for discrete Fourier transform (DFT) processing based on the timing difference; and
an FFT unit adapted to DFT process the signals using the timing of the DFT window,
wherein the control unit is adapted to adjust the timing of the window so that a variance of an error of the demodulated signal is minimized.
24. The receiver of claims 23 , further comprising a joint channel estimation unit configured to determine a joint channel estimate associated with the first and the second cell.
25. The receiver of claim 23 , wherein the control unit is further configured determine a ratio between a signal power of the second cell and a signal power of the first cell and to adjust the timing of the window based on the ratio.
26. The receiver of claim 25 , further comprising a joint channel estimation unit configured to determine a joint channel estimate associated with the first and the second cell.
27. The receiver of claim 23 , wherein the cell search unit is further adapted to obtain a power delay profile of the first cell and a power delay profile of the second cell, the power delay profiles comprising a number of channel taps having respective tap powers, and
the control unit is further adapted to adjust the timing of the window by minimizing the sum, over all channel taps, of the respective tap power multiplied with a respective number of samples that are covered by the FFT window but are outside a symbol being estimated.
28. The receiver of claim 27 , further comprising a joint channel estimation unit configured to determine a joint channel estimate associated with the first and the second cell.
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US14/562,694 US20150094108A1 (en) | 2008-12-19 | 2014-12-06 | Receiver and a method for mobile communications |
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EP08172437A EP2200245B1 (en) | 2008-12-19 | 2008-12-19 | A receiver and a method for mobile communications |
US14568809P | 2009-01-19 | 2009-01-19 | |
PCT/EP2009/067030 WO2010069903A1 (en) | 2008-12-19 | 2009-12-14 | A receiver and a method for mobile communications |
US201113140009A | 2011-08-26 | 2011-08-26 | |
US14/274,206 US8934842B2 (en) | 2008-12-19 | 2014-05-09 | Receiver and a method for mobile communications |
US14/562,694 US20150094108A1 (en) | 2008-12-19 | 2014-12-06 | Receiver and a method for mobile communications |
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US14/562,694 Abandoned US20150094108A1 (en) | 2008-12-19 | 2014-12-06 | Receiver and a method for mobile communications |
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EP2200245B1 (en) * | 2008-12-19 | 2012-08-15 | Telefonaktiebolaget L M Ericsson (publ) | A receiver and a method for mobile communications |
CN102118825B (en) * | 2009-12-31 | 2013-12-04 | 华为技术有限公司 | Method for realizing multipoint joint transmission, terminal and system |
US20130107785A1 (en) * | 2011-11-02 | 2013-05-02 | Qualcomm Incorporated | Tracking loop enhancements for mitigating signal interference and adjusting signal power |
US9014114B2 (en) * | 2011-12-14 | 2015-04-21 | Qualcomm Incorporated | User equipment reference signal-based timing estimation |
WO2016086956A1 (en) | 2014-12-01 | 2016-06-09 | Telefonaktiebolaget Lm Ericsson (Publ) | Cell search and connection procedures in a cellular communication device |
CN106878205B (en) * | 2015-12-10 | 2019-07-05 | 电信科学技术研究院 | A kind of timing offset estimation method and device |
CN109379306B (en) * | 2017-08-11 | 2021-10-15 | 中兴通讯股份有限公司 | Method and device for processing received signal |
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2008
- 2008-12-19 EP EP08172437A patent/EP2200245B1/en not_active Not-in-force
-
2009
- 2009-12-14 JP JP2011541372A patent/JP5431498B2/en not_active Expired - Fee Related
- 2009-12-14 RU RU2011129793/07A patent/RU2518511C2/en active
- 2009-12-14 WO PCT/EP2009/067030 patent/WO2010069903A1/en active Application Filing
- 2009-12-14 US US13/140,009 patent/US8768258B2/en not_active Expired - Fee Related
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2014
- 2014-05-09 US US14/274,206 patent/US8934842B2/en not_active Expired - Fee Related
- 2014-12-06 US US14/562,694 patent/US20150094108A1/en not_active Abandoned
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US8077696B2 (en) * | 2006-02-14 | 2011-12-13 | Sony Corporation | Wireless communication apparatus and wireless communication method |
US20080137524A1 (en) * | 2006-12-12 | 2008-06-12 | Trueposition, Inc. | Location of Wideband OFDM Transmitters With Limited Receiver Bandwidth |
US8768258B2 (en) * | 2008-12-19 | 2014-07-01 | Telefonaktiebolaget Lm Ericsson (Publ) | Receiver and a method for mobile communications |
US8934842B2 (en) * | 2008-12-19 | 2015-01-13 | Telefonaktiebolaget L M Ericsson (Publ) | Receiver and a method for mobile communications |
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Also Published As
Publication number | Publication date |
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JP5431498B2 (en) | 2014-03-05 |
US20110300819A1 (en) | 2011-12-08 |
JP2012513137A (en) | 2012-06-07 |
US8934842B2 (en) | 2015-01-13 |
RU2518511C2 (en) | 2014-06-10 |
WO2010069903A1 (en) | 2010-06-24 |
US8768258B2 (en) | 2014-07-01 |
EP2200245A1 (en) | 2010-06-23 |
RU2011129793A (en) | 2013-01-27 |
EP2200245B1 (en) | 2012-08-15 |
US20140248847A1 (en) | 2014-09-04 |
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