Method and apparatus for activating and deactivating component carriers

This application relates to wireless communications.

An important feature of LTE-A (Long Term Evolution Advanced) is higher data rates. This is supported by allowing the Wireless Transmit/Receive Unit (WTRU) to transmit and receive data on multiple LTE component carriers simultaneously on both the uplink and downlink. This is called carrier aggregation.

Transmitting and receiving on multiple carriers significantly increases the power consumption of the WTRU. The power consumption of the analog front end (which represents a significant percentage of the total power consumption in that WTRU) scales linearly over the bandwidth or multiple aggregated fundamental frequency blocks (i.e. component carriers). known to be proportional. Enabling and disabling additional component carriers on demand and on-the-fly conserves WTRU resources (e.g., Hybrid Automatic Repeat Request (HARQ) processing (Channel Quality Indicator (CQI)). ) and SRS (Sounding Reference Signal) reporting), buffer occupancy and buffer management (e.g. BSR (Buffer Status Report) reporting, and scheduling processes), and providing power consumption savings. is important.

A method and apparatus are described for performing bandwidth aggregation by simultaneously monitoring and processing a number of simultaneously non-adjacent or contiguous component carriers in the downlink. A WTRU may be configured by an eNodeB to support additional component carriers. Additional preconfigured component carriers can be used. Various methods for enabling or disabling additional component carriers are also described.

A more detailed understanding can be obtained from the following description, given by way of example in connection with the accompanying drawings.

<figref num="1">1 illustrates a wireless communication system including an eNodeB and a WTRU; FIG.</figref><figref num="2">2 is a block diagram of the eNodeB of FIG. 1; FIG.</figref><figref num="3">2 is a block diagram of the WTRU of FIG. 1; FIG.</figref><figref num="4">Fig. 3 shows a procedure for monitoring and processing component carriers;</figref><figref num="5">Fig. 3 shows a procedure for monitoring and processing component carriers;</figref>

In future references, the term "WTRU" includes, but is not limited to, User Equipment (UE), Mobile Stations, Fixed or Mobile Subscriber Units, Pagers, Mobile Phones, Personal Digital Assistants (PDAs). information terminal), computer, or any other type of user device capable of operating in a wireless environment.

As used hereinafter, the term "eNodeB" is used without limitation to refer to base stations, site controllers, APs (access points), or any other type of interface device capable of operating in a wireless environment. include.

FIG. 1 shows wireless communication system 100 including eNodeB 105 and WTRU 110 . The eNodeB 105 is configured to send an RRC (Radio Resource Control) connection reconfiguration message 115 to the WTRU 110 .

Various methods and apparatus are described for enabling or disabling transmission and reception on different carriers in an LTE-A system that employs carrier aggregation.

Transition to Connected Mode In standby mode, the WTRU 110 monitors and processes only a single component carrier. Standby mode procedures such as SI (System Information) acquisition and PI (Paging Indication) monitoring are transparent to the WTRU's 110 multi-carrier capabilities. Schemes such as cell selection and cell reselection can be the same with or without carrier aggregation (hereinafter referred to as bandwidth aggregation) capability, or as an input to system selection, The bandwidth aggregation capabilities of the infrastructure (eNodeB 105) can be considered. However, when the WTRU 110 transitions to RRC Connected mode (typically through an RRC connection request), the WTRU 110 informs the network of the WTRU's capabilities for bandwidth aggregation.

The WTRU bandwidth aggregation capability may be defined as the number of simultaneous non-contiguous component carriers that can be monitored and processed simultaneously in the downlink for each band. An alternative metric can be the number of RF (Radio Frequency) receivers (different receivers handle non-adjacent carriers) and the largest bandwidth of each receiver. Consider one example with five component carriers: carriers 1 and 2 are adjacent to each other, carriers 3, 4 and 5 are not, and carriers 3, 4 and 5 are adjacent.

It is also possible to define the WTRU bandwidth aggregation capability as the number of simultaneously contiguous carriers that can be monitored and processed simultaneously in the downlink for each band.

It is also possible to define the WTRU bandwidth aggregation capability as the largest supported bandwidth of aggregated contiguous carriers, not just the number of carriers but also the bandwidth.

It is also possible to define the WTRU bandwidth aggregation capability as the largest total bandwidth of aggregated carriers (neighboring or non-adjacent).

It is also possible to define the WTRU bandwidth aggregation capability as the maximum bandwidth supported per single carrier (according to the current WTRU capabilities of LTE).

Component Carrier RRC Configuration After the WTRU has informed the network about the WTRU's bandwidth capabilities in the RRC connection procedure, an eNodeB that supports bandwidth aggregation may configure additional component carriers (i.e. preconfigured A WTRU can be configured to support additional component carriers). This shall be done by an RRC connection reconfiguration message carrying information enabling the WTRU to set up monitoring (granting and allocation) of one or more additional downlink and/or uplink carriers. can be done. Information contained in the RRC connection reconfiguration message includes cell identification, carrier center frequency, carrier bandwidth, carrier direction (uplink or downlink), and activation and synchronization of additional preconfigured component carriers. may contain other information needed to timely set up the

One RRC connection reconfiguration message is sufficient to set up more than one component carrier by accumulating the previously described information for all preconfigured additional component carriers.

Receipt of the RRC connection reconfiguration message alone may not enable monitoring and processing of additional component carriers immediately or after some delay. In this case, only an explicit or implicit enable command may allow the WTRU to begin monitoring and processing additional carriers, as described below. Alternatively, the RRC connection reconfiguration message may include a field that tells whether monitoring and processing should begin after the reconfiguration procedure has successfully completed. This is useful in setting up to verify that additional pre-configured component carriers are operational. Alternatively, receipt of the RRC connection reconfiguration message enables monitoring and processing of additional component carriers immediately or after some delay.

The RRC connection reconfiguration message allows the WTRU to set up additional component carriers controlled by another eNodeB, such as timing advance and other synchronization related information. May contain additional information.

The RRC connection reconfiguration message can provide one specific C-RNTI (Cell Radio Network Temporary Identifier) for each additional component carrier.

The RRC connection reconfiguration message allocates, for efficiency, a bit combination to each preconfigured additional component carrier up to the maximum number of concurrent additional component carriers supported, and the allocated bit combination so that the enabling or disabling of individual component carriers is mentioned.

[mechanism for enabling or disabling pre-configured additional component carriers]

MAC Control Element Enabling or disabling a pre-configured additional carrier or a predefined subset of pre-configured additional carriers is controlled by the reception of a MAC (Medium Access Control) CE (Control Element). can occur when This enabling or disabling can be performed after a predefined (fixed or configurable through higher layer signaling) delay, or immediately after receipt of the MAC CE. This will be implemented by a new type of MAC CE called MAC_CE_Activation control element.

The MAC_CE_Enable control element may contain a field of bit combinations to indicate which preconfigured carriers are enabled or disabled. Alternatively, the carriers that are enabled or disabled can be indicated by the C-RNTI value used for transmission of MAC PDUs containing MAC Control Elements. A MAC_CE_ENABLE control element can enable or disable multiple carriers at the same time by aggregating bit combinations or sending multiple MAC PDUs using different C-RNTIs. .

Indication of whether the command corresponds to enable or disable can be performed by setting a bit or implied based on the current enable or disable state of the carrier. Alternatively, it can be based on the carrier on which the MAC PDU was received. For example, if a MAC CE is included in a MAC PDU received on a given carrier (e.g., an "anchor carrier" or a "serving cell"), the command is It is understood that it is for activation of the indicated carrier. If a MAC CE is included in a MAC PDU received on a carrier (there may be no explicit indication of the carrier within the MAC CE itself), the command , or alternatively a predefined set of carriers.

In another alternative, all MAC_CE_validations are always received on a specific carrier (eg, the carrier corresponding to the serving cell).

Enable on request Physical Downlink Control Channel (PDCCH) on a specific carrier (e.g. "anchor carrier") with new Downlink Control Information (DCI) format (or modified DCI format for LTE-A) Receiving is performed on preconfigured additional uplink (PUSCH) or downlink (PDSCH) carriers (or a predefined subset of preconfigured additional uplink or downlink carriers). The WTRU may be informed of what is to be done in X subframes. (newnew carrier.) This delay allows the WTRU's analog front end to adapt to the new carrier. PLL (Phase-Locked Loop) and AGC (Automatic Gain Control) settling time and frequency synchronization. The new DCI format includes fields that associate preconfigured carriers with activations, as described above. This allows the WTRU to only monitor the PDCCH from a single carrier (eg, a specific carrier called the 'anchor carrier' or the carrier corresponding to the serving cell), thus saving battery. An indication from the anchor carrier may be for a single grant or allocation on additional component carriers. In this case, HARQ feedback corresponding to grants or allocations may also be delayed (with respect to PDCCH transmission) compared to existing systems. Alternatively, an indication from the anchor carrier that it should begin monitoring PDCCH on additional component carriers or a subset of component carriers until this carrier (or these carriers) is disabled. WTRU can be notified.

A PDCCH received with the new DCI format (or modified DCI format for LTE-A) on a carrier (e.g., an "anchor carrier") is time-delayed on a preconfigured additional component carrier. allocated (PRB (Physical Resource Block), MCS (Modulation and Coding Set), and the like). The delay is based on the WTRU's ability to tune and synchronize to preconfigured component carriers. This delay can be fixed or variable based on WTRU capabilities. Time-delayed assignments are already used for uplink assignments - ie 4 subframe delays. However, this method allows the WTRU to know more in advance about the likelihood of the next uplink transmission compared to existing systems. Such prior knowledge may be beneficial for uplink scheduling decisions. The same approach can be used for additional preconfigured component carriers. This provides the benefit that additional pre-configured component carriers are activated on demand by pre-allocating resources.

[Implicit Enable] The amount of traffic received on the downlink (PHY (Physical), MAC, RLC (Radio Link Control), or PDCP (Packet Data Convergence Protocol)) in a predetermined or configured time. ) exceeds a predetermined or configured threshold, implicit activation of one or some number of carriers may occur. There are several defined thresholds, each corresponding to activation of a particular carrier. For example, if the amount of traffic exceeds Vl, carrier Cl can be activated, and if the amount of traffic exceeds V2, carrier C2 can be activated, and so on.

Also, on certain uplink carriers associated with the enabling downlink carrier, the WTRU may transmit (Random Access Channel (RACH), Physical Uplink Control Channel (PUCCH), or Physical Uplink Shared Channel (PUSCH)). ), implicit activation of one or some number of carriers may occur. This association may be predefined or provided to the WTRU through RRC signaling (system information or dedicated signaling).

When a downlink carrier is enabled, the WTRU will start receiving on the PDCCH configured for this carrier (if PDCCH is defined per carrier) and transmission on PUCCH will be configured to send feedback information for

Implicit Invalidation Implicit invalidation can be performed based on an invalidation timer specific to the validity of the additional component carrier. For example, only the anchor carrier is valid during a web browsing session. When the download begins, it will start allocating PRBs on additional component carriers pre-configured for this WTRU. Once the download is complete, the network stops allocating resources to preconfigured additional component carriers for that WTRU. After some deactivation timer (which is specific to the preconfigured carrier) expires, the WTRU stops monitoring the PDCCH (i.e. dedicated PDCCH per carrier) and uses the front end radio resources allocated to this carrier. Stop. Alternatively, the WTRU may stop monitoring PDCCH for a carrier after expiration of a timing alignment timer (or other timer) specifically defined for this carrier. MAC received on that carrier Such timing alignment timers can be restarted based on the receipt of the timing alignment MAC control element from the PDU.

For activation on demand and control channels shared on the anchor carrier, the WTRU is assigned to a preconfigured additional component carrier as soon as no time-delayed assignment to this carrier is received. It is possible to stop the front end resource. It is more appropriate for the WTRU to wait several consecutive subframes without allocating additional preconfigured component carriers before deactivating front end resources associated with these carriers. can determine if there is

Implicit override may also be based on radio conditions. As an example, front-end radio resources can be de-allocated if the carrier's channel conditions are below some minimum threshold for a period of time.

Explicit Deactivation Order on PDCCH Explicit deactivation by sending a component carrier specific deactivation order so that the WTRU no longer needs to monitor the PDCCH (dedicated PDCCH per carrier). can be executed. The order can be sent using the PDCCH with the new DCI format on the anchor carrier for dedicated channels. Alternatively, the deactivation order using PDCCH can be sent only for preconfigured additional component carriers.

Enabling or Disabling in DRX Connected Mode The MAC DRX configuration remains the same for carrier aggregation. The on-duration and DRX cycle are the same for configured carriers (e.g., "anchor carriers" or serving.Cells).

A DRX Inactivity timer (DRX_Inactivity_timer) running in the WTRU may be started or restarted when a PDCCH is received over a pre-configured additional component carrier enabled for new transmissions. .

A DRX deactivation timer may also be started or restarted when a scheduled grant for an enabled preconfigured additional component carrier is received for a new transmission.

Alternatively, the MAC DRX configuration can have unique DRX deactivation timers for each additional pre-configured component carrier. The DRX deactivation timer associated with the carrier will be started or restarted when a PDCCH allocation is received on this carrier. This would allow the WTRU to effectively disable these preconfigured carriers until the next receive period cycle while the anchor carriers are in a valid time.

The logic previously described for the DRX disable timer can also be applied to other DRX timers, such as ON_Duration_Timer and DRX_Retransmission_Timer.

FIG. 2 is a block diagram of eNodeB 105 of FIG. eNodeB 105 includes antenna 205 , receiver 210 , processor 215 , and transmitter 220 . Receiver 210 is configured to receive a signal indicative of the bandwidth aggregation capabilities of WTRU 110 . Transmitter 220 is configured to transmit RRC connection reconfiguration messages to WTRU 110 .

FIG. 3 is a block diagram of WTRU 110 of FIG. WTRU 110 includes antenna 305 , receiver 310 , processor 315 , transmitter 320 , and DRX (Discontinuous Reception) disable timer 325 .

WTRU 110 monitors and processes component carriers. Receiver 310 of WTRU 110 is configured to monitor and process single component carriers. Transmitter 320 of WTRU 110 is configured to transmit a signal indicative of bandwidth aggregation capabilities of WTRU 110 . Receiver 310 is further configured to receive an RRC connection reconfiguration message. Processing unit 315 of WTRU 110 is configured to set up to monitor and process at least one additional pre-configured component carrier.

Receiver 310 can further be configured to receive MAC CE, and processing unit 315 can be configured to enable or disable pre-configured additional component carriers.

Additional preconfigured component carriers may be enabled or disabled immediately, or may be enabled or disabled after a predefined delay, in response to receipt of MAC CE. The preconfigured additional component carrier can be an uplink carrier or a downlink carrier.

The WTRU 110 may monitor and process single component carriers while in standby mode.

In one example, the bandwidth aggregation capability can represent a certain number of concurrent non-contiguous component carriers that can be monitored and processed concurrently in the downlink for each band.

In another example, bandwidth aggregation capability can represent the largest bandwidth among a certain number of RF receivers and each receiver.

In yet another example, bandwidth aggregation capability can represent a certain number of concurrently contiguous carriers that can be monitored and processed simultaneously in the downlink for each band.

In yet another example, the bandwidth aggregation capability can represent the maximum supported bandwidth among aggregated adjacent carriers.

In yet another example, bandwidth aggregation capability can represent the maximum total bandwidth among aggregated carriers.

In yet another example, the bandwidth aggregation capability can represent the maximum bandwidth supported per single carrier.

A bandwidth aggregation capability can represent more than one of the examples described above.

In another scenario, the receiver 310 specifies a PDCCH in DCI format that indicates that transmission and reception with additional preconfigured uplink or downlink carriers are to occur in a certain number of subframes. can be configured to receive on a carrier of The processor 315 can be configured to set up to monitor and process preconfigured carriers.

FIG. 4 shows a procedure 400 for monitoring and processing component carriers. In step 405, the WTRU monitors and processes single component carriers. At step 410, the WTRU transmits a signal indicative of the WTRU's bandwidth aggregation capabilities. At step 415, the WTRU receives the RRC connection reconfiguration message. At step 420, the WTRU sets up to monitor and process at least one additional pre-configured component carrier. In step 425, the WTRU enables or disables preconfigured additional component carriers in response to receiving the MAC CE.

FIG. 5 shows a procedure 500 for monitoring and processing component carriers. In step 505, the WTRU monitors and processes single component carriers. In step 510, the WTRU transmits a PDCCH on a particular carrier in DCI format, indicating that transmission/reception with additional preconfigured uplink or downlink carriers will occur in a certain number of subframes. to receive. At step 515, the WTRU sets up to monitor and process preconfigured carriers.

Embodiments 1. A method for monitoring and processing component carriers implemented by a WTRU comprising monitoring and processing a single component carrier and generating a signal representing the WTRU's bandwidth aggregation capability. receiving an RRC (Radio Resource Control) connection reconfiguration message; and setting up at least one preconfigured additional component carrier for monitoring and processing. how to.

2. The method of embodiment 1, further comprising: receiving a MAC (Medium Access Control) CE (Control Element); and enabling or disabling the preconfigured additional component carrier. described method.

3. The method of embodiment 2, wherein the preconfigured additional component carrier is immediately enabled or disabled in response to receiving the MAC CE.

4. The method of embodiment 2, wherein the preconfigured additional component carriers are enabled or disabled after a predefined delay.

5. The method of any of embodiments 1-4, wherein the preconfigured additional component carrier is an uplink carrier.

6. The method of any of embodiments 1-4, wherein the preconfigured additional component carrier is a downlink carrier.

7. The method as in any one of embodiments 1-6, wherein the WTRU monitors and processes the single component carrier while in standby mode.

8. The method of embodiments 1-7 wherein the bandwidth aggregation capability represents a number of concurrent non-contiguous component carriers that can be monitored and processed simultaneously in the downlink for each band. Any method described.

9. The method of any of embodiments 1-7, wherein the bandwidth aggregation capability represents a number of RF receivers and the maximum bandwidth of each receiver.

10. Any one of embodiments 1-7 wherein the bandwidth aggregation capability represents a number of simultaneously contiguous carriers that can be monitored and processed simultaneously in the downlink for each band described method.

11. The method of any of embodiments 1-7, wherein the bandwidth aggregation capability represents a maximum supported bandwidth of aggregated adjacent carriers.

12. The method of any of embodiments 1-7, wherein the bandwidth aggregation capability represents a maximum total bandwidth among aggregated carriers.

13. The method as in any one of embodiments 1-7, wherein the bandwidth aggregation capability represents the maximum bandwidth supported per single carrier.

14. A method implemented by a WTRU for monitoring and processing component carriers comprising monitoring and processing a single component carrier and preconfigured additional uplink or downlink carriers. Receiving a PDCCH (Physical Downlink Control Channel) representing that transmission and reception with a carrier will be performed in a certain number of subframes on a specific carrier in a DCI (Downlink Control Information) format; and setting up to monitor and process the detected carrier.

15. A WTRU for monitoring and processing a component carrier, the receiver configured to monitor and process a single component carrier and to transmit a signal indicative of the bandwidth aggregation capability of the WTRU a transmitter configured, said receiver further configured to receive a Radio Resource Control (RRC) connection reconfiguration message, and at least one preconfigured additional component carrier for monitoring and processing. a processing unit configured to set up.

16. The receiver is further configured to receive MAC (Medium Access Control) CE (Control Element), and the processing unit enables or disables the preconfigured additional component carrier. 16. The WTRU of embodiment 15, wherein the WTRU is configured to:

17. The WTRU of embodiment 16, wherein the preconfigured additional component carriers are immediately enabled or disabled in response to receiving the MAC CE.

18. The WTRU of embodiment 16, wherein the preconfigured additional component carriers are enabled or disabled after a predefined delay.

19. The WTRU of any of embodiments 15-18, wherein the preconfigured additional component carrier is an uplink carrier.

20. The WTRU of any of embodiments 15-18, wherein the preconfigured additional component carrier is a downlink carrier.

21. The WTRU of any of embodiments 15-20, wherein the WTRU monitors and processes the single component carrier while in standby mode.

22. The method of embodiments 15-21 wherein the bandwidth aggregation capability represents a certain number of concurrent non-contiguous component carriers that can be monitored and processed simultaneously in the downlink for each band. WTRU as described in any.

23. The WTRU of any of embodiments 15-21, wherein the bandwidth aggregation capability represents a number of RF receivers and the largest bandwidth of each receiver.

24. Any one of embodiments 15-21, wherein the bandwidth aggregation capability represents a number of simultaneously contiguous carriers that can be monitored and processed simultaneously in the downlink for each band WTRU as stated.

25. The WTRU of any of embodiments 15-21, wherein the bandwidth aggregation capability represents a maximum supported bandwidth of aggregated adjacent carriers.

26. The WTRU of any of embodiments 15-21, wherein the bandwidth aggregation capability represents a maximum total bandwidth among aggregated carriers.

27. The WTRU of any of embodiments 15-21, wherein the bandwidth aggregation capability represents the maximum bandwidth supported per single carrier.

28. A WTRU for monitoring and processing a component carrier, the receiver configured to monitor and process a single component carrier and a preconfigured additional uplink carrier or downlink carrier; PDCCH (Physical Downlink Control Channel), which indicates that transmission and reception with a carrier will be performed in a certain number of subframes, is configured to be received on a specific carrier in a DCI (Downlink Control Information) format. A WTRU comprising a receiver and a processing unit configured to set up to monitor and process said preconfigured carrier.

Although features and elements are described above in particular combinations, each feature or element can be used alone without other features and elements, or in various combinations with or without other features and elements. can be used. Any method or flow diagram provided herein may be embodied in a computer program, software, or firmware embodied in a computer-readable storage medium for execution by a general-purpose computer or processing device. can do. Examples of computer-readable storage media include magnets such as ROM (Read Only Memory), RAM (Random Access Memory), registers, cache memory, semiconductor memory devices, internal hard disks and removable disks. It includes media, magneto-optical media, and optical media such as CD-ROM discs and DVDs (Digital Versatile Discs).

Examples of suitable processors include general purpose processors, special purpose processors, conventional processors, DSPs (Digital Signal Processors), multiple microprocessors, one associated with a DSP core. or multiple microprocessors, controllers, microcontrollers, ASICs (Application Specific Integrated Circuits), ASSPs (Application Specific Standard Products), FPGA (Field Programmable Gate Array) circuits, or any other type of IC (Integrated Circuit (integrated circuit), and/or state machines.

Processing associated with software to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, MME (Mobility Management Entity) or EPC (Evolved Packet Core), or any host computer The device can be used. WTRU is a software defined radio (SDR), as well as cameras, video camera modules, videophones, speakerphones, vibration devices, speakers, microphones, TV transceivers, hands-free handsets, keyboards, Bluetooth® module, FM (Frequency Modulated) wireless unit, NFC (Near Field Communication) module, LCD (Liquid Crystal Display) display unit, OLED (Organic Light-Emitting) Diode) display unit, digital music player, media player, video game player module, internet browser, and/or any WLAN (Wireless Local Access Network) module or UWB (Ultra Wide Band) module, etc. It can be used in conjunction with modules implemented in hardware and/or software, including components.