Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04J—MULTIPLEX COMMUNICATION
  • H04J11/00—Orthogonal multiplex systems, e.g. using WALSH codes
  • H04J11/0069—Cell search, i.e. determining cell identity [cell-ID]
  • H04J11/0086—Search parameters, e.g. search strategy, accumulation length, range of search, thresholds
• • 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
  • H04J—MULTIPLEX COMMUNICATION
  • H04J11/00—Orthogonal multiplex systems, e.g. using WALSH codes
  • H04J11/0023—Interference mitigation or co-ordination
  • H04J11/005—Interference mitigation or co-ordination of intercell interference
• • 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
  • H04L5/0001—Arrangements for dividing the transmission path
  • H04L5/0028—Variable division
• • 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
  • H04B2201/70702—Intercell-related aspects
• • 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
  • H04B2201/7097—Direct sequence modulation interference
  • H04B2201/709727—GRAKE type RAKE receivers
• • 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
  • H04L5/0001—Arrangements for dividing the transmission path
  • H04L5/0014—Three-dimensional division
  • H04L5/0016—Time-frequency-code
  • H04L5/0021—Time-frequency-code in which codes are applied as a frequency-domain sequences, e.g. MC-CDMA
• • 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
  • H04L5/0091—Signalling for the administration of the divided path, e.g. signalling of configuration information

Definitions

• the technical field relates to radio communications systems, and more particularly, to multi- carrier receivers.
• the Wideband Code Division Multiple Access (WCDMA) Third Generation Partnership Project (3 GPP) Release 5 extended the WCDMA specification with the High Speed Downlink Packet Access (HSDPA), and Release 6 introduced Enhanced Dedicated Channel (E-DCH), often referred as Enhanced Uplink (EUL) or High Speed Uplink Packet Access (HSUPA).
• HSDPA and HSUPA together are called High Speed Packet Access (HSPA) which greatly improves the achievable bit rate over the air interface.
• 3GPP Release 7 introduced higher-order modulation and multiple input multiple output (MIMO) for HSDPA to further improve the achievable bit rate.
• MIMO multiple input multiple output
• a primary objective of a multi-carrier (MC) system is to achieve high data rate.
• a multi-carrier arrangement with frequency division duplex (FDD) can be described as a set of downlink carriers linked to a set of uplink carriers.
• the downlink carriers can be adjacent or non-adjacent in the frequency domain, and the same holds for the uplink carriers.
• Multi-carrier arrangements can also be used in time division duplex (TDD) systems.
• the component carriers in a multi-carrier system may also belong to different frequency bands.
• WCDMA/HSPA operating on multiple 5 MHz carrier frequencies is referred to as Multi- Carrier WCDMA or Multi-Carrier HSPA.
• E-UTRAN Telecommunications System Terrestrial Radio Access Network
• multiple component carriers such as four 20 MHz carriers in the downlink and two 20 MHz in the uplink (for FDD) can be used to enhance the data rate.
• a multi-carrier system uses more than one carrier in the downlink and/or the uplink.
• One of the multi-carriers is called the primary or anchor carrier and the remaining one(s) is(are) called secondary or supplementary carriers.
• the anchor carrier contains all physical channels including all common control channels.
• the secondary carriers may or may not contain all physical channels; for instance, they may lack some of the common downlink control channels.
• the anchor carrier in the downlink and in the uplink should support legacy operation based on a single carrier, which means the downlink anchor carrier should contain all common channels so that legacy single-carrier UEs are served.
• a multi-carrier UE also needs the anchor carrier to transmit all common control channels for acquisition of the frame timing, neighbor cell measurements, etc.
• Any single-carrier system can be evolved to a multi-carrier system to increase data rate.
• the future advancements of HSPA, E-UTRAN, and other systems will likely result in multiple carriers both in the uplink and the downlink, (e.g., 4 downlink carriers and 2 uplink carriers).
• Some receivers can receive multi-carrier transmissions— others cannot. Some receivers have interference cancellation capability— some do not. Even for those that do have interference cancellation capability, there are differences in those capabilities. For example, one type of receiver might be able to specifically cancel inter-cell interference, while another type of receiver cannot.
• the inter-cell interference is contributed by the signals transmitted from the neighboring cells.
• the anchor/primary carrier contains all the common channels, depending upon the network implementation, some of the common control channels may not be transmitted on the secondary carriers. The absence of a common control channel, like a synchronization channel, on the secondary carrier increases the complexity of the inter- cell interference cancellation in the receiver.
• a multi-carrier UE with an inter-cell interference cancellation receiver in a WCDMA type system is unable to use such a secondary synchronization channel (S-SCH) to identify the scrambling code group for an interfering neighbor cell.
• S-SCH secondary synchronization channel
• the channel impulse responses of the interfering signals from each of the interfering cells must be determined.
• the UE needs information about the master timing in each of the neighbor cells and the scrambling codes used in those neighbor cells.
• the UE will have to extensively search to determine the scrambling codes used in the neighbor cells which drains UE power and slows down the synchronization process.
• One approach to this problem might be to predefine that in multi-carrier systems, the UE enables the inter-cell interference cancellation only on the primary anchor carrier but not on the secondary carriers. But this approach leads to reduced performance on the secondary carrier because only non inter-cell interference cancellation receiver configurations may be used on the secondary carrier. If there are multiple secondary carriers, the performance loss will be higher.
• RRC Radio Resource Control
• the network implementation determines whether all or a sub-set of common channels (e.g., SCH) are sent on the secondary carriers in a multi-carrier system. It is preferable that UEs perform inter-cell interference cancellation if possible, but in the absence of receiving the SCH on a secondary carrier, it is more demanding for the UE to perform inter- cell interference cancellation, and therefore, not necessarily desirable. On the other hand, if the SCH is available on a secondary carrier, then inter-cell interference cancellation can be performed at least with less complexity, power, and delay.
• a radio node e.g., a mobile radio terminal, a base station, etc.
• a radio node can receive multiple RF carriers and includes a first radio receiver configuration and a second radio receiver configuration.
• the radio node includes electronic circuitry that is configured to select a first radio receiver configuration to receive channel information on the secondary carrier if a common channel in the cell is transmitted on the secondary carrier. If the common channel is not transmitted on the secondary carrier, the radio node selects the second radio receiver configuration to receive the first channel information on the secondary carrier.
• the technology may be applied to receiving multiple secondary carriers.
• the radio node may use information received on the primary carrier to determine whether the common channel is transmitted on the secondary carrier. In one non- limiting example embodiment, the radio node determines whether the common channel is transmitted on the secondary carrier by performing a cell search on the secondary carrier. In another non-limiting example embodiment, the radio node determines whether the common channel is transmitted on the secondary carrier using timing and channel power information associated with the serving cell on the primary carrier. The timing may include slot and frame timing for the primary carrier, and the channel power information may include an estimated common channel power delay profile on the primary carrier. If the common channel is a synchronization channel, then the determination of whether the common channel is transmitted on the secondary carrier may be made by correlating the secondary carrier with one or more synchronization codes using the timing acquired for the primary carrier in each cell.
• the primary and secondary carriers are time aligned, i.e., their transmit timings in each base station are the same or almost the same.
• the time alignment error requirement is typically pre-defined.
• the transmit timing difference between the two carriers is required to be within 1 A TC according to TS 25.104, where Tc is the duration of 1 WCDMA chip (1 Tc ⁇ 260 ns).
• the first radio receiver configuration is one in which a radio receiver cancels inter-cell interference
• the second radio receiver configuration is one in which a radio receiver does not cancel inter-cell interference.
• the radio receiver in the first radio receiver configuration and the second radio receiver configuration cancels intra-cell interference.
• the intra-cell interference is contributed by the signals transmitted from the serving cell and noise. Accordingly, the first radio receiver configuration may be more complex than the second radio receiver configuration since the former is required to process and cancel both inter-cell and intra-cell interferences.
• the first receiver configuration is a type 3i radio receiver configuration
• the second receiver configuration is a type 3 radio receiver configuration
• the first channel is a High-Speed Physical Downlink Shared Channel (HS-PDSCH)
• the common channel includes a primary synchronization channel and a secondary synchronization channel.
• the UE receiver performance requirements corresponding to type 3i radio receiver configuration are specified as the enhanced performance requirements type 3i in 3GPP specification TS 25.101, "User Equipment (UE) radio transmission and reception (FDD)."
• the UE receiver performance requirements corresponding to type 3 radio receiver configuration are specified as the enhanced performance requirements type 3 in 3GPP specification TS 25.101.
• the second receiver configuration is a type 2 and type 1 radio receiver configurations whose receiver performance requirements are also specified in TS 25.101.
• the first channel is a channel carrying user data such as a physical downlink shared channel (PDSCH) or a channel carrying control information as a physical downlink control channel (PDCCH).
• PDSCH physical downlink shared channel
• PDCCH physical downlink control channel
• the first channel may be any channel received by the UE.
• the invention also extends to a device adapted to receive multiple radio frequency carriers in accordance with the above.
• the device can typically be implemented in a module comprising a micro controller or a micro processor operating on a set of computer program instructions stored in a memory, which instructions when executed by the module causes the module to perform power control in accordance with the method as described above.
• Figure 1 illustrates an example multi-carrier communications system
• Figure 2 illustrates an example multi-carrier cellular communications system showing intra- cell and inter-cell interference
• Figure 3 is a function block diagram illustrating a non-limiting example multi-carrier radio terminal with different types of interference cancellation capabilities
• Figure 4 is a flow chart illustrating non-limiting example procedures for selecting a first or second radio receiver configuration to receive channel information on a secondary channel
• Figure 5 is a flow chart illustrating example procedures in accordance with a specific but non- limiting implementation for selecting a first or second radio receiver configuration to receive channel information on a secondary channel;
• Figure 6 is function block diagram illustrating an example control processor for a non-limiting example implementation.
• Figure 7 is function block diagram illustrating a different example control processor for the non-limiting example implementation in Figure 6.
• the technology may be used in any type of cellular radio communications.
• the term mobile radio terminal encompasses any kind of radio communications terminal/device like user equipment (UE), PDAs, cell phones, laptops, etc.
• the technology described in this application may be used any radio communications system where multiple carriers are supported at least in one direction.
• a WCDMA network which communicates with one or more user equipments (UEs) over a Uu air interface.
• UEs user equipments
• RNCs radio network controllers
• a WCDMA radio access network (RAN) may also be called Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN).
• UMTS Universal Mobile Telecommunications System
• UTRAN Universal Mobile Telecommunications System
• the WCDMA RAN handles all tasks that relate to radio access control such as radio resource management and handover control.
• the core network connects the access network to one or more external networks (Public Switched Telephone Network PSTN, Internet, etc.).
• the user equipment is connected to one or more radio base stations (Node Bs) over the WCDMA air interface.
• Node Bs radio base stations
• One or more base stations are coupled to an RNC over an Iub interface, and RNCs communicate over an Iur interface.
• Figure 1 illustrates an example multi-carrier communications system with a base station 10 communicating over an air interface with a mobile radio terminal 12 (a UE) using multiple carriers.
• the base station transmits an anchor or primary carrier and a secondary carrier
• the mobile radio 12 transmits a single uplink carrier.
• the mobile radio 12 is a multi-carrier radio in the sense that it can at least receive multiple carriers, but it also might be able to transmit using multiple carriers. While the examples below assume that the primary and secondary carriers are transmitted in the downlink from the base station 10 to the mobile radio 12, the technology also applies in the uplink direction for multi-carrier transmitting mobile radios, where the base station is the receiver and the mobile the transmitter.
• a UE in a dual cell-HSDPA (DC-HSDPA) operation which is specified in Technical Specification 3GPP TS 25.214 release 8, is able to simultaneously receive HSDPA traffic over two downlink carrier frequencies transmitted in the same frequency band from a single serving base station sector.
• One uplink carrier for a DC- HSDPA UE is not tied to one of the two downlink carriers.
• the anchor carrier has all the physical channels including Forward Dedicated Physical Channel (F-DPCH), E-DCH HARQ Acknowledgement Indicator Channel (E-HICH), E-DCH Absolute Grant Channel (E-AGCH), and E-DCH Relative Grant Channel (E-RGCH).
• F-DPCH Forward Dedicated Physical Channel
• E-HICH E-DCH HARQ Acknowledgement Indicator Channel
• E-AGCH E-DCH Absolute Grant Channel
• E-RGCH E-DCH Relative Grant Channel
• Figure 2 illustrates an example multi-carrier cellular communications system showing intra- cell and inter-cell interference.
• the serving cell 14 includes a base station 10 that transmits to mobile terminals MTA and MTC in its cell over primary and secondary carriers.
• a base station 10 that transmits to mobile terminals MTA and MTC in its cell over primary and secondary carriers.
• neighboring cell 16 also includes a base station 10 that transmits information which is received by mobile terminal MTB but which also may interfere with the radio communications in the serving cell 14 - inter-cell interference. Transmissions from terminal MTB in the neighbor cell 16 may also be a source of inter-cell interference. Uplink transmissions from the mobile terminals in the serving cell 14 are a source of intra-cell interference.
• FIG. 3 is a function block diagram illustrating a non-limiting example multi-carrier radio terminal UE 12 with different types of interference cancellation capabilities.
• the UE 12 includes one or more antennas 30 for receiving and transmitting radio signals with another radio station like a base station in the example.
• a control processor 24 controls the overall operation of the UE 12 and is connected to user interface circuitry 28, transmitter circuitry 26, and receiving circuitry 20 and 22.
• the control processor 24 dynamically or semi- statically selects which type of receiver or receiver configuration will be used to receive signals from a particular transmitting station.
• Block 20 shows an inter-cell interference cancellation receiver type/configuration
• block 22 shows an intra-cell interference cancellation receiver type/configuration.
• the receiving circuitry may include a more sophisticated and complex receiver type/configuration and a less sophisticated and complex receiver type/configuration.
• the receiving circuitry 20 and 22 can be implemented in one receiver, e.g., as two different receiver configurations, or in two or more receivers.
• One example way of implementing different receiver configurations in one receiver is to use a DSP with different coding depending on the receiver type/configuration selected or desired.
• enhanced UE receiver performance requirements are also specified in TS 25.101.
• the UE In order to fulfill these enhanced requirements, the UE must implement an advanced receiver, e.g., with receiver diversity, a chip level equalizer, and generalized rake receivers (G-RAKE) or similar receiver structures. These enhancements boost the achievable downlink bit rate.
• UE receiver performance requirements for various advanced receivers are specified as enhanced receiver type 1 (receiver diversity), enhanced receiver type 2 (chip level equalizer), enhanced receiver type 3 (combined receiver diversity and equalizer), and type 3i (combined receiver diversity and inter-cell interference cancellation receiver).
• the enhanced receiver performance specification does not preclude UE vendors from implementing advanced receivers beyond the specified enhanced requirements.
• Enhanced performance requirements are not confined to HSDPA in WCDMA.
• Enhanced requirements also exist for example for a number of reception scenarios: DCH, MBMS, E-DCH downlink channels etc.
• DCH Downlink Control
• MBMS Downlink Control
• E-DCH E-DCH downlink channels etc.
• the focus in this description is on a multi-carrier HSDPA reception scenario. But that focus is not limiting on the broad ranging application of the technology.
• different types of radio receivers have different levels of performance gain achieved by eliminating or at least mitigating different types of interference.
• There are various sources and forms of interference e.g. intra-cell, inter-cell, inter-stream interferences etc.
• intra-cell interference is common due to lack of orthogonality between the channelization codes as they pass through a multipath fading channel.
• inter-cell interference exists in single or tight reuse systems such as in CDMA and OFDMA-based LTE system and is generated typically from a number of neighbor cells.
• MIMO transmission uses two or more streams of data to achieve higher SINR. But multi-stream transmission also leads to inter-stream interference, which can be eliminated or considerably reduced by using an appropriate receiver.
• the enhanced receiver type 3 (a.k.a G-RAKE 2 receiver in a symbol-level implementation) can eliminate intra-cell interference to attain a significant performance gain over the classical rake receiver.
• the enhanced receiver type 3i (a.k.a G-RAKE 2+ receiver in a symbol-level implementation) can eliminate both intra-cell and inter-cell interferences to attain significant performance gain over the classical rake receiver.
• the parametric solution must detect a certain number of interfering cells to suppress (ideally the strongest interfering cells). For instance, the UE in a WCDMA system could identify the scrambling codes used in the strongest interfering cells and use this information to eliminate or minimize the interference. The UE further needs to dynamically estimate the channel response of the interfering cell(s) in order to suppress the interference. Estimating the channel response can be done in several ways, where one example way is to separately estimate the power delay profile (PDP) and use it to determine the channel tap delays and separately estimate the complex weight for each of the tap delays.
• PDP power delay profile
• Non-limiting examples of other receiver configurations include receivers that attempt to create a replica of the received interfering signal and subtract it from the desired signal.
• the downlink common control channels include a primary synchronization channel (P-SCH) which carries a primary synchronization code (PSC), a secondary synchronization channel (S-SCH), which carries a secondary synchronization code (SSC), a primary common pilot channel CPICH which carries scrambling code information, and a broadcast channel (BCH) which carries system information including a master information block (MIB) and one or more system information blocks (SIB).
• P-SCH and S-SCH together are known as the SCH channel.
• LTE also uses common channels similar to those used in UTRAN/WCDMA/HSPA.
• Common channels in LTE include primary synchronization signals (PSS), secondary synchronization signals (SSS), reference signals (equivalent to pilot signals on the CPICH), and broadcast channel.
• PSS primary synchronization signals
• SSS secondary synchronization signals
• reference signals equivalent to pilot signals on the CPICH
• broadcast channel is split into physical broadcast channel (PBCH), which carries the MIB, and PDSCH, which carries SIBs.
• the P-SCH and S-SCH enable the UE to determine the slot and frame timing, as well as identify a limited set of primary scrambling codes containing the specific primary scrambling codes used by the cell from which the P-SCH and S-SCH are transmitted.
• the limited set is called the scrambling code group.
• the CPICH is used to pinpoint which of the primary scrambling codes contained in the scrambling code group indicated by P-SCH and S-SCH that is used by the cell being identified which indicates one of the 512 possible physical cell identities.
• Each primary scrambling code is associated with 15 secondary scrambling codes through a one-to-one mapping.
• the UE does not need to search for secondary scrambling codes during the initial synchronization procedure.
• the identification of slot/frame boundary and identification of scrambling code for the serving cell may be done through a staged approach.
• Stage 1 find the slot boundary using the P-SCH.
• Stage 2 find the frame boundary and the scrambling code group using P- SCH and S-SCH, where each scrambling code group contains 8 primary scrambling codes.
• Stage 3 using CPICH, determine the best primary scrambling code candidate out of the 8 contained in the scrambling code group identified in Stage 2.
• the anchor carrier contains all the common channels.
• some of the common control channels may not be transmitted on the secondary carriers; it might for example be the case that only the CPICH is transmitted on the secondary carrier to assist the UE for the
• the absence of SCH channels on the secondary carrier increases the complexity of the inter-cell interference cancellation receiver because the UE cannot make use of the P-SCH and S-SCH to identify the slot timing, frame timing and scrambling code group.
• the UE In the absence of synchronization signals on secondary carriers, the UE must perform extensive searching (over all 8192 scrambling codes in this non- limiting example) and many delay hypothesizes to determine the scrambling codes used in the neighbor cells. This will drain UE power, slow down the synch process, and lead to worse performance due to delayed processing.
• One way to determine if there are synchronization signals on the secondary carriers is to perform a typical cell search procedure on the secondary carriers for all neighboring cells.
• the UE scans for the SCH channel using a correlator on many different timings/delays on the secondary carrier(s).
• the SCH channel is detected on the secondary carrier only when the correlator generates an output that exceeds a predetermined threshold. But this cell search approach requires a significant amount of processing resources to correlate all delays for all scrambling codes.
• a multi-carrier capable UE receives data from the serving cell on the anchor carrier and the serving cell on at least one secondary carrier.
• the UE determines the slot and frame timing and scrambling code group of the serving cell on the anchor carrier from the P-SCH, S-SCH, and CPICH channels respectively (step SlO).
• the UE also determines the power delay profile of the serving cell on the anchor carrier from the CPICH channel (step S 12).
• the specific details for determining the slot and frame timing and the channel power delay profile are known to those skilled in the art and not repeated here to simplify the description.
• the UE uses the timing and power delay profile of the serving cell on the anchor carrier to search for the presence of common channel signals
• the cells on the anchor and secondary carriers in the same base station have the same frame timing.
• the anchor and secondary carriers are either co-located, (i.e., in co-located or co-sited base stations), or located in the same base station and thus will be perceived by the UE as having the same received timing and channel power delay profile. Due to practical constraints, there may be a small misalignment between the frame timing of the primary and secondary carriers, e.g., in the order of less than a WCDMA chip.
• the search for the SCH for example on the serving cell belonging to the secondary carrier may be performed by correlating over all possible PSC codes or by using any suitable approach based on the prior knowledge of the power delay profile on the anchor (or primary) carrier.
• the UE determines that the common channel signals (e.g., the SCH signals) are transmitted on the serving cell on the secondary carrier, then the UE enables a more advanced receiver type/configuration, labeled here as receiver type A, for receiving data and/or signaling on the secondary carrier (step S 16).
• Receiver type A can for example attempt to cancel inter-cell interference.
• the complexity of an inter-cell interference cancelling receiver is greatly reduced when the SCH is present on the secondary carrier because the UE can make use of the SCH to perform a traditional cell search on the secondary carrier to identify the strongest interfering cell(s).
• the UE enables a less advanced receiver type/configuration, labeled receiver type B.
• the receiver type B can either be based on receiver diversity and/or based on an equalizer that cancels only intra-cell interference.
• the UE dynamically or semi-dynamically adapts or enables an appropriate receiver type/configuration for reception on a secondary carrier in a multi-carrier system depending upon whether a common channel is transmitted, e.g., whether a SCH is transmitted.
• Information regarding whether the common channel (e.g., SCH) is present on the secondary carrier can be acquired by the UE by various mechanisms. For instance, the UE may be signaled by the network or via a pre-defined rule as to whether the synchronization signals are transmitted on the secondary carriers or not.
• receiver type A which has more advanced capabilities than receiver type B is an enhanced receiver type 3i described above which can significantly cancel inter-cell interference from certain number of strongest neighbor cells. It may also cancel intra-cell interference.
• receiver type B is enhanced receiver type 3 described above which is a relatively less complex receiver and may not substantially cancel inter-cell interference from the neighbor cells. However, it may still be capable of cancelling intra-cell interference.
• FIG. 6 is function block diagram illustrating an example control processor 24 for a non- limiting example implementation based on the cell search approach described above.
• the control processor 24 includes a correlator 30 for correlating a received secondary carrier with a PSC code for a secondary carrier.
• the output of the correlator 30 is compared to a threshold by a selector 32, and if a correlator output exceeds the threshold indicating detection of the SCH on the secondary carrier, the selector 32 selects the 3i receiver type/configuration 34. Otherwise, the selector 32 selects the less sophisticated 3 receiver type/configuration 36.
• FIG 7 is function block diagram illustrating a different example control processor for the approach described above in Figure 5.
• the control processor 24 includes an analyzer 38 for analyzing a received secondary carrier with respect to the PDP of the anchor carrier determined using the CPICH and the determined anchor carrier timing information as described above for Figure 5.
• the output of the analyzer 38 is used by a selector 32 to selects the 3i receiver type/configuration 34 if the SCH is detected on the secondary carrier. Otherwise, the selector 32 selects the less sophisticated 3 receiver type/configuration 36.
• the technology described above is applicable to any multi-carrier system with any number of carriers.
• a multi-carrier system might have 4 downlink carriers with 3 carriers being secondary ones.
• the UE can use the technology to independently adapt the receiver type/configuration for each of the secondary carriers.
• the technology is not limited to the types of receivers specifically described.
• the technology allows a radio receiver to use a first receiver type for receiving data and/or control information on one or more secondary carrier channel(s) if one or more common channel(s) are transmitted on the corresponding secondary carrier. Otherwise, the radio receiver uses a second receiver type for receiving data and/or control information on one or more secondary carrier channel(s).
• the UE uses an enhanced receiver type 3i (inter-cell interference cancellation receiver with receiver diversity, e.g., G-RAKE2+) for receiving HS-PDSCH from a secondary carrier if SCH channels or signals (primary and secondary synchronization signals) are transmitted on the corresponding secondary carrier. Otherwise, the UE uses an enhanced receiver type 3 (non inter-cell interference cancellation receiver with receiver diversity, e.g., G-RAKE2) for receiving HS-PDSCH from the said secondary carrier.
• G-RAKE2+ inter-cell interference cancellation receiver with receiver diversity
• G-RAKE2+ non inter-cell interference cancellation receiver with receiver diversity
• Dynamically switching between receiver types for receiving on the secondary carriers depending upon whether the secondary carrier contains common channel information like synchronization signals offers many benefits. Examples include:

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• 2010
  • 2010-06-04 US US12/794,421 patent/US8599772B2/en active Active
  • 2010-06-24 JP JP2012518876A patent/JP5624135B2/ja not_active Expired - Fee Related
  • 2010-06-24 EP EP10729702A patent/EP2452442A2/en not_active Ceased
  • 2010-06-24 MY MYPI2011006331A patent/MY153306A/en unknown
  • 2010-06-24 WO PCT/EP2010/058966 patent/WO2011003744A2/en not_active Ceased

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