US20060262834A1 - Multiuser detection of differing data rate signals - Google Patents
Multiuser detection of differing data rate signals Download PDFInfo
- Publication number
- US20060262834A1 US20060262834A1 US10/547,485 US54748506A US2006262834A1 US 20060262834 A1 US20060262834 A1 US 20060262834A1 US 54748506 A US54748506 A US 54748506A US 2006262834 A1 US2006262834 A1 US 2006262834A1
- Authority
- US
- United States
- Prior art keywords
- data
- real time
- detection device
- signals
- data signals
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- 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
- H04B1/69—Spread spectrum techniques
- H04B1/707—Spread spectrum techniques using direct sequence modulation
- H04B1/7097—Interference-related aspects
- H04B1/7103—Interference-related aspects the interference being multiple access interference
-
- 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
- H04B1/69—Spread spectrum techniques
- H04B1/707—Spread spectrum techniques using direct sequence modulation
- H04B1/7097—Interference-related aspects
- H04B1/7103—Interference-related aspects the interference being multiple access interference
- H04B1/7105—Joint detection techniques, e.g. linear detectors
- H04B1/71055—Joint detection techniques, e.g. linear detectors using minimum mean squared error [MMSE] detector
-
- 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
- H04B1/69—Spread spectrum techniques
- H04B1/707—Spread spectrum techniques using direct sequence modulation
- H04B1/7097—Interference-related aspects
- H04B1/7103—Interference-related aspects the interference being multiple access interference
- H04B1/7107—Subtractive interference cancellation
- H04B2001/71077—Partial interference cancellation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B2201/00—Indexing scheme relating to details of transmission systems not covered by a single group of H04B3/00 - H04B13/00
- H04B2201/69—Orthogonal indexing scheme relating to spread spectrum techniques in general
- H04B2201/707—Orthogonal indexing scheme relating to spread spectrum techniques in general relating to direct sequence modulation
- H04B2201/70703—Orthogonal indexing scheme relating to spread spectrum techniques in general relating to direct sequence modulation using multiple or variable rates
- H04B2201/70705—Rate detection
Definitions
- the present invention relates to a wireless communications network, and more particularly, for multiuser detection in a frequency division duplex system.
- Signals can be sent in frequency division duplex (FDD) mode as shown in FIG. 1 , for example a plurality of voice signals (V 1 , V 2 , and V 3 ) and a plurality of data signals (D 1 and D 2 ).
- the voice signals are transmitted typically at a lower power than the data signals, since the voice signals can be transmitted with a lower data rate (such as by a higher spreading factor) without a significant loss in signal quality.
- a voice signal can be transmitted with a spreading factor of 64 (64 chips per data bit), whereas a data signal may be transmitted with a spreading factor of four chips per data bit, due to the higher transmission rate.
- FIG. 1 several voice and data signals can be transmitted in the same spectrum.
- the voice signals usually need a small amount of system bandwidth, and accordingly transmission power.
- a larger bandwidth is required which typically requires higher transmission power levels.
- the uplink of the FDD universal mobile telecommunications system supports a potentially large number of simultaneously transmitted codes.
- the signature sequences of the codes are highly non-structured with long codes having a period of one frame (38,400 chips). Short signature sequences are permitted as an option; however, even these short sequences have a period of 256 chips.
- TDD time division duplex
- the signature sequences are far shorter and more rigidly structured, with a period of 16 chips.
- MUDs multi-user detectors
- MMSE minimum mean square error
- PICs successive interference cancellers
- PICs Parallel interference cancellers
- PICs are complex and do not necessarily deliver significant performance improvements because their effectiveness falls as the total interference rises. Accordingly, PICs tend to perform poorly for recovery of voice user data in the presence of several high data rate users.
- a first detector receives a received signal and extracts the data signals from the received signal.
- a hard decision converter converts soft symbols outputted by the first detector into hard symbols.
- An interference canceller extracts the voice signals from the received signal.
- a second detector is connected to the output of the interference canceller, and extracts the individual voice signals. The second detector is a different detector type than the first detector.
- FIG. 1 is a block diagram of an example FDD transmission block with multiple voice and data signals.
- FIG. 2 is a simplified diagram of a transmitter and a receiver using a multiuser detector constructed in accordance with the present invention.
- FIG. 3 is a block diagram of the multiuser detector shown in FIG. 2 .
- FIG. 4 is a flow chart of multiuser detection of differing data rate signals.
- FIGS. 5A, 5B and 5 C are illustrations of reception blocks.
- a wireless transmit/receive unit includes, but is not limited, to a user equipment, a mobile station, a fixed or mobile subscriber unit, a pager, or any other type of device capable of operating in a wireless environment.
- a base station includes, but is not limited to, a base station, a Node-B, a site controller, an access point, or any other interfacing device in a wireless environment.
- the background refers to an FDD wireless system, the embodiments can be applied to various wireless systems, where both high data and low data rate services are transmitted in a shared spectrum.
- FIG. 2 illustrates an embodiment of a multiuser detector as used in a wireless communication system operating in accordance with the present invention.
- a transmitter 200 and a receiver 202 communicate with each other via a wireless radio air interface 208 .
- the transmitter 200 may be located at a WTRU or at a base station.
- the receiver 202 may be located at the WTRU and/or the base station.
- Data symbols to be transmitted to the receiver 202 are processed by a modulation and spreading device 204 at the transmitter 200 .
- the modulation and spreading device 204 spreads the data with the codes and at a spreading factors assigned to the communications carrying the data.
- the communications are radiated by an antenna 206 or antenna array of the transmitter 200 through the wireless radio interface 208 .
- the communications are received at an antenna 210 or antenna array of the receiver 202 .
- the received signal is sampled by a sampling device 212 , such as at the chip rate or at a multiple of the chip rate, to produce a received vector.
- the received vector is processed by a channel estimation device 216 to estimate the channel impulse responses for the received communications.
- the channel estimation device 216 uses a training sequence in the received communication to estimate the channel experienced by each communication.
- a multiuser detection device 214 uses the codes of the received communications and the estimated impulse responses to estimate soft symbols of the spread data.
- the multiuser detector 214 receives the sampled signal from the sampling device 212 .
- the samples are provided to a blind adaptive detector 304 and a data buffer 306 .
- the outputted soft symbols from the detector 304 are sent to symbol processing to recover the high data rate data (not shown in FIG. 3 ) and to a hard decision converter 310 .
- the signal is sent to an interference canceller 312 , where the signals of the high data rate users are removed from the sampled signal (the high data rate users' signals are passed to the interference canceller 312 via the data buffer 306 ), leaving voice signals to be processed by a voice grade user detector 314 .
- the blind adaptive detector 304 uses MMSE detectors for the high data rate users, although other detectors may be used.
- the detector 304 is based on a blind adaptive multiuser detector (MUD), a constrained optimization approach, and array processing techniques. These techniques are used in order to deliver MMSE performance to all of the high data rate users.
- MOD blind adaptive multiuser detector
- the detection of the high data rate users is followed by an interference cancellation stage in which the estimated signals sent by these users are removed from the received signal by the interference canceller 312 .
- the remaining signal typically consists of a large number of voice grade users.
- voice grade users can be processed by using standard matched-filtering techniques, e.g., RAKE receivers. Alternately, a low-complexity detection scheme or parallel interference cancellation techniques may be applied.
- matched-filtering techniques e.g., RAKE receivers.
- a low-complexity detection scheme or parallel interference cancellation techniques may be applied.
- To reduce the complexity of the voice user detection it is desirable to use simplier detectors, although more complex detectors may be used. To illustrate, in alternate embodiments, it may be desirable to utilize more complex detector that could be used for other purposes by the WTRU or base station.
- the detectors 304 , 314 are blind detectors and do not have complete knowledge of the received codes. These components can be implemented on a single integrated circuit, multiple integrated circuits,
- FIG. 4 is a flow chart for differing data rate multiuser detection, and is explained with the illustrations of FIGS. 5A, 5B and 5 C.
- the receiver receives both high data rate and voice signals in a shared spectrum, step 400 .
- two high data rate signals, D 1 and D 2 are received along with three voice signals, V 1 , V 2 , and V 3 , received along with three voice signals, V 1 , V 2 and V 3 , and noise, N.
- FIG. 5B is an illustration of the treatment of the spectrum by the detector 304 .
- the detector 304 treats the voice signals as noise, N.
- the high data rate signals can be determined by many means, such as by received power levels, a priori knowledge, etc. Since all of the signals are not processed by this detector, a lower complexity detector can be used. This is further facilitated by the detector 304 only processing high data rate signals typically having similar received power levels.
- the contribution of the high data rate signals is canceled from the received vector, step 404 .
- the samples resemble FIG. 5C .
- the contribution of the high data rate signals, D 1 and D 2 is removed.
- a data detection is performed on the voice signals, V 1 , V 2 and V 3 , step 406 . If a detection of data signals V 1 , V 2 and V 3 was performed on the uncancelled signal of FIG. 5A , typically, D 1 , D 2 and the noise would all be treated as noise and/or interference, instead of only the noise N as in FIG. 5C .
- the voice users are typically at similar power levels. Although the power levels for high data rate services may vary, these services typically have much higher power levels. Since data detectors typically perform better for equal power signals, the separation on the signals tends to improve performance.
- the exemplary embodiment of the multiuser detector 214 provides three general functions: (1) support for a limited number of high performance high data rate users at a minimal cost to the basic (i.e., voice grade) capacity; (2) a low-complexity receiver that is effective for a large number of approximately equal power users (i.e., voice grade users); and (3) a receiver structure which supports a family of algorithms, rather than a single algorithm, so that certain parameters are adaptable to the specific needs of different potential customers. In alternate embodiments, some of the functions may be sacrificed in favor of other functionality.
- the partitioning is done because it is the natural partition for the application of third generation (3G) mobile telephony.
- the method itself is not limited to such partitioning and more levels may be defined with data detection and successive interference cancellation used repeatedly at each level, as shown in FIG. 3 .
- Real time signals are for communications that need to be transmitted in relay time, such as voice or video conferencing.
- real time signals require continuous dedicated resources to facilitate the real time transfer.
- Non-real time signals are signals that do not require real time transmission, such as internet browsing. Although these signals may use continuous dedicated resources, they may use discontinuous resources.
- One approach is to detect the real time signals with the initial detector and detect the non-real time signals after interference cancellation. Alternately, the initial detector may detect the non-real time signals followed by the real time signals.
Abstract
Description
- The present invention relates to a wireless communications network, and more particularly, for multiuser detection in a frequency division duplex system.
- Signals can be sent in frequency division duplex (FDD) mode as shown in
FIG. 1 , for example a plurality of voice signals (V1, V2, and V3) and a plurality of data signals (D1 and D2). The voice signals are transmitted typically at a lower power than the data signals, since the voice signals can be transmitted with a lower data rate (such as by a higher spreading factor) without a significant loss in signal quality. For example, a voice signal can be transmitted with a spreading factor of 64 (64 chips per data bit), whereas a data signal may be transmitted with a spreading factor of four chips per data bit, due to the higher transmission rate. As illustrated inFIG. 1 , several voice and data signals can be transmitted in the same spectrum. For voice communications (V1, V2 and V3), the voice signals usually need a small amount of system bandwidth, and accordingly transmission power. For high rate data signals, a larger bandwidth is required which typically requires higher transmission power levels. - The uplink of the FDD universal mobile telecommunications system (UMTS) supports a potentially large number of simultaneously transmitted codes. The signature sequences of the codes are highly non-structured with long codes having a period of one frame (38,400 chips). Short signature sequences are permitted as an option; however, even these short sequences have a period of 256 chips. By comparison, in time division duplex (TDD) mode where multiuser detection techniques are more typically employed, the signature sequences are far shorter and more rigidly structured, with a period of 16 chips.
- The lack of structure of the signature sequence in FDD combined with a large number of users that the receiver may be required to support makes it infeasible to implement standard multi-user detectors (MUDs), such as decorrelator and minimum mean square error (MMSE) type receivers in such systems. Other popular MUD receiver structures are not necessarily suitable here either. For example, successive interference cancellers (PICs) do not perform well with a large number of codes of approximately the same power. Parallel interference cancellers (PICs), are complex and do not necessarily deliver significant performance improvements because their effectiveness falls as the total interference rises. Accordingly, PICs tend to perform poorly for recovery of voice user data in the presence of several high data rate users.
- Additionally, there is significant amount of data shuffling that occurs between the physical channel demodulation and the channel decoders. This makes joint channel demodulation and decoding techniques nearly infeasible.
- Accordingly, it is desirable to have alternate MUD-type receiver designs for such systems.
- A first detector receives a received signal and extracts the data signals from the received signal. A hard decision converter converts soft symbols outputted by the first detector into hard symbols. An interference canceller extracts the voice signals from the received signal. A second detector is connected to the output of the interference canceller, and extracts the individual voice signals. The second detector is a different detector type than the first detector.
- A more detailed understanding of the invention may be had from the following description of the preferred embodiments, given by way of example and to be understood in conjunction with the accompanying drawings, wherein:
-
FIG. 1 is a block diagram of an example FDD transmission block with multiple voice and data signals. -
FIG. 2 is a simplified diagram of a transmitter and a receiver using a multiuser detector constructed in accordance with the present invention. -
FIG. 3 is a block diagram of the multiuser detector shown inFIG. 2 . -
FIG. 4 is a flow chart of multiuser detection of differing data rate signals. -
FIGS. 5A, 5B and 5C are illustrations of reception blocks. - Hereafter, a wireless transmit/receive unit (WTRU) includes, but is not limited, to a user equipment, a mobile station, a fixed or mobile subscriber unit, a pager, or any other type of device capable of operating in a wireless environment. When referred to hereafter, a base station includes, but is not limited to, a base station, a Node-B, a site controller, an access point, or any other interfacing device in a wireless environment. Although the background refers to an FDD wireless system, the embodiments can be applied to various wireless systems, where both high data and low data rate services are transmitted in a shared spectrum.
-
FIG. 2 illustrates an embodiment of a multiuser detector as used in a wireless communication system operating in accordance with the present invention. Atransmitter 200 and areceiver 202 communicate with each other via a wirelessradio air interface 208. Thetransmitter 200 may be located at a WTRU or at a base station. Thereceiver 202 may be located at the WTRU and/or the base station. - Data symbols to be transmitted to the
receiver 202 are processed by a modulation and spreadingdevice 204 at thetransmitter 200. The modulation and spreadingdevice 204 spreads the data with the codes and at a spreading factors assigned to the communications carrying the data. The communications are radiated by anantenna 206 or antenna array of thetransmitter 200 through thewireless radio interface 208. - At the
receiver 202, the communications, possibly along with other transmitters' communications, are received at anantenna 210 or antenna array of thereceiver 202. The received signal is sampled by asampling device 212, such as at the chip rate or at a multiple of the chip rate, to produce a received vector. The received vector is processed by achannel estimation device 216 to estimate the channel impulse responses for the received communications. Thechannel estimation device 216 uses a training sequence in the received communication to estimate the channel experienced by each communication. Amultiuser detection device 214, uses the codes of the received communications and the estimated impulse responses to estimate soft symbols of the spread data. - As shown in
FIG. 3 , themultiuser detector 214 receives the sampled signal from thesampling device 212. The samples are provided to a blindadaptive detector 304 and adata buffer 306. The outputted soft symbols from thedetector 304 are sent to symbol processing to recover the high data rate data (not shown inFIG. 3 ) and to ahard decision converter 310. After thehard decision converter 310, the signal is sent to aninterference canceller 312, where the signals of the high data rate users are removed from the sampled signal (the high data rate users' signals are passed to theinterference canceller 312 via the data buffer 306), leaving voice signals to be processed by a voicegrade user detector 314. - Preferably, the blind
adaptive detector 304, uses MMSE detectors for the high data rate users, although other detectors may be used. In one embodiment, thedetector 304 is based on a blind adaptive multiuser detector (MUD), a constrained optimization approach, and array processing techniques. These techniques are used in order to deliver MMSE performance to all of the high data rate users. - The detection of the high data rate users is followed by an interference cancellation stage in which the estimated signals sent by these users are removed from the received signal by the
interference canceller 312. The remaining signal typically consists of a large number of voice grade users. These voice grade users can be processed by using standard matched-filtering techniques, e.g., RAKE receivers. Alternately, a low-complexity detection scheme or parallel interference cancellation techniques may be applied. To reduce the complexity of the voice user detection, it is desirable to use simplier detectors, although more complex detectors may be used. To illustrate, in alternate embodiments, it may be desirable to utilize more complex detector that could be used for other purposes by the WTRU or base station. In one embodiment, thedetectors -
FIG. 4 is a flow chart for differing data rate multiuser detection, and is explained with the illustrations ofFIGS. 5A, 5B and 5C. The receiver receives both high data rate and voice signals in a shared spectrum,step 400. As illustrated inFIG. 5A in terms of received power, two high data rate signals, D1 and D2, are received along with three voice signals, V1, V2, and V3, received along with three voice signals, V1, V2 and V3, and noise, N. - Preferably, a data detection is performed on the high data rate signals,
step 402.FIG. 5B is an illustration of the treatment of the spectrum by thedetector 304. Thedetector 304 treats the voice signals as noise, N. The high data rate signals can be determined by many means, such as by received power levels, a priori knowledge, etc. Since all of the signals are not processed by this detector, a lower complexity detector can be used. This is further facilitated by thedetector 304 only processing high data rate signals typically having similar received power levels. - Using the symbols produced by the
detector 304, the contribution of the high data rate signals is canceled from the received vector,step 404. After cancellation, the samples resembleFIG. 5C . As shown inFIG. 5C , the contribution of the high data rate signals, D1 and D2, is removed. A data detection is performed on the voice signals, V1, V2 and V3,step 406. If a detection of data signals V1, V2 and V3 was performed on the uncancelled signal ofFIG. 5A , typically, D1, D2 and the noise would all be treated as noise and/or interference, instead of only the noise N as inFIG. 5C . For a typical implementation where high data rate services are being separated from voice services, the voice users are typically at similar power levels. Although the power levels for high data rate services may vary, these services typically have much higher power levels. Since data detectors typically perform better for equal power signals, the separation on the signals tends to improve performance. - The exemplary embodiment of the
multiuser detector 214 provides three general functions: (1) support for a limited number of high performance high data rate users at a minimal cost to the basic (i.e., voice grade) capacity; (2) a low-complexity receiver that is effective for a large number of approximately equal power users (i.e., voice grade users); and (3) a receiver structure which supports a family of algorithms, rather than a single algorithm, so that certain parameters are adaptable to the specific needs of different potential customers. In alternate embodiments, some of the functions may be sacrificed in favor of other functionality. - While the description above partitions the users into two categories, data and voice, the partitioning is done because it is the natural partition for the application of third generation (3G) mobile telephony. The method itself is not limited to such partitioning and more levels may be defined with data detection and successive interference cancellation used repeatedly at each level, as shown in
FIG. 3 . - Another partitioning of the received signals is into real time signals and non-real time signals. Real time signals are for communications that need to be transmitted in relay time, such as voice or video conferencing. Typically, real time signals require continuous dedicated resources to facilitate the real time transfer. Non-real time signals are signals that do not require real time transmission, such as internet browsing. Although these signals may use continuous dedicated resources, they may use discontinuous resources. One approach is to detect the real time signals with the initial detector and detect the non-real time signals after interference cancellation. Alternately, the initial detector may detect the non-real time signals followed by the real time signals.
Claims (17)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/547,485 US20060262834A1 (en) | 2003-03-03 | 2004-03-01 | Multiuser detection of differing data rate signals |
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US45159303P | 2003-03-03 | 2003-03-03 | |
US10/731,456 | 2003-12-09 | ||
US10/731,456 US7075973B2 (en) | 2003-03-03 | 2003-12-09 | Multiuser detection of differing data rate signals |
PCT/US2004/006231 WO2004079717A2 (en) | 2003-03-03 | 2004-03-01 | Multiuser detection of differing data rate signals |
US10/547,485 US20060262834A1 (en) | 2003-03-03 | 2004-03-01 | Multiuser detection of differing data rate signals |
Publications (1)
Publication Number | Publication Date |
---|---|
US20060262834A1 true US20060262834A1 (en) | 2006-11-23 |
Family
ID=32965558
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/731,456 Expired - Fee Related US7075973B2 (en) | 2003-03-03 | 2003-12-09 | Multiuser detection of differing data rate signals |
US10/547,485 Abandoned US20060262834A1 (en) | 2003-03-03 | 2004-03-01 | Multiuser detection of differing data rate signals |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/731,456 Expired - Fee Related US7075973B2 (en) | 2003-03-03 | 2003-12-09 | Multiuser detection of differing data rate signals |
Country Status (10)
Country | Link |
---|---|
US (2) | US7075973B2 (en) |
EP (1) | EP1606791A4 (en) |
JP (1) | JP2006520128A (en) |
KR (2) | KR100828530B1 (en) |
CN (1) | CN1754323A (en) |
CA (1) | CA2517432A1 (en) |
MX (1) | MXPA05009349A (en) |
NO (1) | NO20054253L (en) |
TW (3) | TWI259665B (en) |
WO (1) | WO2004079717A2 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050212970A1 (en) * | 2004-03-26 | 2005-09-29 | Joskin Yves R | Video frame grabber apparatus and method |
US20100238981A1 (en) * | 2006-05-11 | 2010-09-23 | Vijay Nagarajan | Interference cancellation in variable codelength systems for multi-acess communication |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6366607B1 (en) | 1998-05-14 | 2002-04-02 | Interdigital Technology Corporation | Processing for improved performance and reduced pilot |
KR100651434B1 (en) * | 2002-10-05 | 2006-11-28 | 삼성전자주식회사 | Apparatus and method for removing interference signals in a receiver of a packet data communication system |
US11516221B2 (en) * | 2019-05-31 | 2022-11-29 | Apple Inc. | Multi-user devices in a connected home environment |
Citations (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6128486A (en) * | 1995-06-30 | 2000-10-03 | Teknopolis Kolster Oy | Reception method and base station receiver |
US20020018454A1 (en) * | 2000-03-15 | 2002-02-14 | Misra Raj Mani | Multi-user detection using an adaptive combination of joint detection and successive interface cancellation |
US20020027730A1 (en) * | 2000-08-15 | 2002-03-07 | Tan Yeongheng | Amplitude modulation detection for hard disc drive write operation |
US20020057730A1 (en) * | 2000-08-04 | 2002-05-16 | Jonas Karlsson | Spreading factor detector |
US20020118784A1 (en) * | 2000-12-26 | 2002-08-29 | Nortel Networks Limited | Apparatus and method to provide spectrum sharing for two or more RF signals occupying an overlapping RF bandwidth |
US20020137546A1 (en) * | 2000-01-24 | 2002-09-26 | Kazuyuki Miya | Radio base station device and radio communication method |
US20030053526A1 (en) * | 1999-10-19 | 2003-03-20 | Interdigital Technology Corporation | Parallel interference cancellation receiver for multiuser detection of CDMA signals |
US20030103558A1 (en) * | 2001-03-14 | 2003-06-05 | Oates John H. | Wireless communication systems and methods for long-code communications for regenerative multiple user detection involving matched-filter outputs |
US20030112904A1 (en) * | 2001-11-16 | 2003-06-19 | Fuller Arthur T.G. | Time variant filter implementation |
US6615030B1 (en) * | 2000-02-09 | 2003-09-02 | Hitachi, Ltd. | Mobile communications system and radio base station apparatus |
US20040090906A1 (en) * | 2002-11-08 | 2004-05-13 | Shimon Moshavi | Reduced complexity MMSE multiuser detection for a multirate CDMA link |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20020057739A1 (en) * | 2000-10-19 | 2002-05-16 | Takumi Hasebe | Method and apparatus for encoding video |
US7209515B2 (en) * | 2001-03-30 | 2007-04-24 | Science Applications International Corporation | Multistage reception of code division multiple access transmissions |
-
2003
- 2003-12-09 US US10/731,456 patent/US7075973B2/en not_active Expired - Fee Related
-
2004
- 2004-03-01 TW TW093105322A patent/TWI259665B/en not_active IP Right Cessation
- 2004-03-01 KR KR1020057016382A patent/KR100828530B1/en not_active IP Right Cessation
- 2004-03-01 MX MXPA05009349A patent/MXPA05009349A/en not_active Application Discontinuation
- 2004-03-01 JP JP2006501212A patent/JP2006520128A/en not_active Withdrawn
- 2004-03-01 KR KR1020077012020A patent/KR20070064378A/en not_active Application Discontinuation
- 2004-03-01 TW TW096104183A patent/TW200803200A/en unknown
- 2004-03-01 EP EP04716161A patent/EP1606791A4/en not_active Withdrawn
- 2004-03-01 CA CA002517432A patent/CA2517432A1/en not_active Abandoned
- 2004-03-01 CN CNA2004800054364A patent/CN1754323A/en active Pending
- 2004-03-01 TW TW093127052A patent/TW200525913A/en unknown
- 2004-03-01 US US10/547,485 patent/US20060262834A1/en not_active Abandoned
- 2004-03-01 WO PCT/US2004/006231 patent/WO2004079717A2/en active Application Filing
-
2005
- 2005-09-14 NO NO20054253A patent/NO20054253L/en not_active Application Discontinuation
Patent Citations (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6128486A (en) * | 1995-06-30 | 2000-10-03 | Teknopolis Kolster Oy | Reception method and base station receiver |
US20030053526A1 (en) * | 1999-10-19 | 2003-03-20 | Interdigital Technology Corporation | Parallel interference cancellation receiver for multiuser detection of CDMA signals |
US20020137546A1 (en) * | 2000-01-24 | 2002-09-26 | Kazuyuki Miya | Radio base station device and radio communication method |
US6615030B1 (en) * | 2000-02-09 | 2003-09-02 | Hitachi, Ltd. | Mobile communications system and radio base station apparatus |
US20020018454A1 (en) * | 2000-03-15 | 2002-02-14 | Misra Raj Mani | Multi-user detection using an adaptive combination of joint detection and successive interface cancellation |
US20020057730A1 (en) * | 2000-08-04 | 2002-05-16 | Jonas Karlsson | Spreading factor detector |
US20020027730A1 (en) * | 2000-08-15 | 2002-03-07 | Tan Yeongheng | Amplitude modulation detection for hard disc drive write operation |
US20020118784A1 (en) * | 2000-12-26 | 2002-08-29 | Nortel Networks Limited | Apparatus and method to provide spectrum sharing for two or more RF signals occupying an overlapping RF bandwidth |
US20030103558A1 (en) * | 2001-03-14 | 2003-06-05 | Oates John H. | Wireless communication systems and methods for long-code communications for regenerative multiple user detection involving matched-filter outputs |
US20030112904A1 (en) * | 2001-11-16 | 2003-06-19 | Fuller Arthur T.G. | Time variant filter implementation |
US20040090906A1 (en) * | 2002-11-08 | 2004-05-13 | Shimon Moshavi | Reduced complexity MMSE multiuser detection for a multirate CDMA link |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050212970A1 (en) * | 2004-03-26 | 2005-09-29 | Joskin Yves R | Video frame grabber apparatus and method |
US7570305B2 (en) * | 2004-03-26 | 2009-08-04 | Euresys S.A. | Sampling of video data and analyses of the sampled data to determine video properties |
US20100238981A1 (en) * | 2006-05-11 | 2010-09-23 | Vijay Nagarajan | Interference cancellation in variable codelength systems for multi-acess communication |
US8064498B2 (en) * | 2006-05-11 | 2011-11-22 | Rambus Inc. | Interference cancellation in variable codelength systems for multi-acess communication |
US8588349B2 (en) | 2006-05-11 | 2013-11-19 | Rambus Inc. | Interference cancellation in variable codelength systems for multi-access communication |
US9036748B2 (en) | 2006-05-11 | 2015-05-19 | Iii Holdings 1, Llc | Interference cancellation in variable codelength systems for multi-access communication |
Also Published As
Publication number | Publication date |
---|---|
TW200803200A (en) | 2008-01-01 |
KR100828530B1 (en) | 2008-05-13 |
EP1606791A2 (en) | 2005-12-21 |
MXPA05009349A (en) | 2005-11-04 |
CN1754323A (en) | 2006-03-29 |
TW200423561A (en) | 2004-11-01 |
NO20054253L (en) | 2005-09-14 |
TWI259665B (en) | 2006-08-01 |
WO2004079717A3 (en) | 2005-06-02 |
JP2006520128A (en) | 2006-08-31 |
CA2517432A1 (en) | 2004-09-16 |
US7075973B2 (en) | 2006-07-11 |
TW200525913A (en) | 2005-08-01 |
WO2004079717A2 (en) | 2004-09-16 |
EP1606791A4 (en) | 2006-06-14 |
KR20070064378A (en) | 2007-06-20 |
KR20050105508A (en) | 2005-11-04 |
US20040202151A1 (en) | 2004-10-14 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP4316500B2 (en) | Group-by-group continuous interference cancellation for block transmission with receive diversity | |
JP4359388B2 (en) | Method and apparatus for joint detection of data in a direct sequence spread spectrum communication system | |
KR100803682B1 (en) | Efficient multiple input multiple output system for multi-path fading channels | |
JP2009177837A (en) | Method for receiving signals in radio communication system, and, radio transmitting/receiving unit | |
KR20050021510A (en) | Scaling using gain factors for use in data detection for wireless code division multiple access communication systems | |
CN101036311A (en) | Use of adaptive filters in CDMA wireless system employing pilot signals | |
US6208684B1 (en) | Cyclic adaptive receivers for DS-CDMA signals | |
US7075973B2 (en) | Multiuser detection of differing data rate signals | |
US8199793B2 (en) | Determination of active spreading codes and their powers | |
US20120027053A1 (en) | Method and apparatus for reducing multi-user processing in wireless communication systems | |
EP1817856B1 (en) | Interference characterisation and removal | |
KR100888839B1 (en) | Method and apparatus for reducing multi-user processing in wireless communication systems | |
KR20070022880A (en) | Method and apparatus for reducing multi-user processing in wireless communication systems |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: INTERDIGITAL TECHNOLOGY CORPORATION, DELAWARE Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:REZNIK, ALEXANDER;ZEIRA, ARIELA;OZLUTURK, FAITH M.;AND OTHERS;REEL/FRAME:018602/0264;SIGNING DATES FROM 20060629 TO 20060706 |
|
AS | Assignment |
Owner name: INTERDIGITAL TECHNOLOGY CORPORATION, DELAWARE Free format text: CORRECTIVE ASSIGNMENT TO CORRECT THE ASSIGNOR'S NAME; SHOULD BE FATIH M. OZLUTURK NOT FAITH M. OZLUTURK PREVIOUSLY RECORDED ON REEL 018602 FRAME 0264;ASSIGNORS:REZNIK, ALEXANDER;ZEIRA, ARIELA;OZLUTURK, FATIH M.;AND OTHERS;REEL/FRAME:019108/0782;SIGNING DATES FROM 20060629 TO 20060706 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |