Virtual carrier configuration and operation for wireless systems with large carrier bandwidth

Apparatus and methods are provided for virtual carrier operation in wireless systems with large carrier bandwidth. In one novel aspect, virtual carrier (VC) with a block of physically contiguous radio resources within a component carrier is configured. In one embodiment, the UE configures a downlink (DL) common virtual carrier (CVC) and an uplink (UL) CVC, which carry control information for the UE, and one or more DL/UL dedicated VCs (DVCs), which carry data services. In one embodiment, the UE obtains the CVC configuration information including the channel bandwidth and the physical location through system information. In another embodiment, the UE obtains DVC configuration through a RRC-layer signaling. In another novel aspect, the UE obtains a VC configuration switch command through either a MAC signal or a PHY signal, and subsequently reconfigures one or more configured VCs based on the received switch command.

TECHNICAL FIELD

The disclosed embodiments relate generally to wireless communication, and, more particularly, to methods and apparatus for efficient operation for large carrier bandwidth.

BACKGROUND

Mobile networks communication continues to grow rapidly. The mobile data usage will continue skyrocketing. New data applications and services will require higher speed and more efficient. Large data bandwidth application continues to attract more consumers. New technologies are developed to meet the growth such as carrier aggregation (CA), which enables operators, vendors, content providers and the other mobile users to meet the increasing requirement for the data bandwidth. However, carrier aggregation assumes multiple RF chains for signal reception even for physically contiguous spectrum, which introduces long transition time to activate more carriers from one carrier for larger data bandwidth and decreases the efficiency of the data transmission.

In frequency bands above 3 GHz, there could be a block of physically continuous spectrum up to hundreds of MHz. The single carrier operation for such large continuous spectrum is more efficient in both the physical (PHY) control, with lower control signaling overhead, and PHY data, with higher trunking gains. It is, therefore, to configure the large contiguous spectrum for large data transmission instead of configuring multiple small spectrum resources. However, from the system level, not all the user equipments (UEs) require large channel bandwidth. Further, for each UE, not all applications require large channel bandwidth. Given that wideband operation requires higher power consumption, the use of the large spectrum resource for control signaling monitoring and low-data-rate services is not ideal for power saving and bandwidth efficiency.

Improvements and enhancements are required for efficient operation for systems with large carrier bandwidth.

SUMMARY

Apparatus and methods are provided for virtual carrier operation in wireless systems with large carrier bandwidth. In one novel aspect, virtual carrier (VC) with a block of physically contiguous radio resources within a component carrier is configured. In one embodiment, the UE acquires synchronization and system information with a first channel bandwidth over one component carrier and one or more component carrier is configured after completing network entry. The UE is configured with a downlink (DL) common virtual carrier (CVC) and an uplink (UL) CVC for each component carrier, wherein the DL CVC and UL CVC carry control information for the UE. The UE is configured with one or more DL/UL dedicated VCs (DVCs), which carry data services for each component carrier. The UE activates the configured VCs over the activated component carriers. In one embodiment, the UE obtains the CVC configuration information including the channel bandwidth and the physical location through system information. In another embodiment, the UE obtains DVC configuration through a RRC-layer signaling. In one embodiment, the UE performs a radio resource management (RRM) measurement on the DL CVC without measurement gap if both the DL CVC and the one or more DL DVCs within a component carrier are switched on; otherwise, the UE performs a RRM measurement on the DL CVC with a measurement gap, when only the one or more DL DVCs within a component carrier are switched on.

In another novel aspect, the UE switches on/off the configured VCs upon receiving the switch command. In one embodiment, the UE obtains a VC configuration switch command and subsequently switch on/off one or more configured VCs based on the received switch command. In one embodiment, the switch command is through a MAC signaling. In another embodiment, the switch command is through a PHY signaling. In yet another embodiment, the UE transmits a triggering switch signal to the network and receives a switch command for UL VCs. The UE performs the VC switch procedure based on the switch command for UL VCs.

DETAILED DESCRIPTION

FIG. 1illustrates a system diagram of a wireless network100with virtual carriers configured in accordance with embodiments of the current invention. Wireless communication system100includes one or more wireless networks each of the wireless communication network has a fixed base infrastructure units, such as receiving wireless communications devices or base unit102103, and104, forming wireless networks distributed over a geographical region. The base unit may also be referred to as an access point, an access terminal, a base station, a Node-B, an eNode-B, or by other terminology used in the art. Each of the base unit102,103, and104serves a geographic area. Backhaul connections113,114and115connect the non-co-located receiving base units, such as102,103, and104. These backhaul connections can be either ideal or non-ideal

A wireless communications device101in wireless network100is served by base station102via uplink111and downlink112. Other UEs105,106,107, and108are served by different base stations. UEs105and106are served by base station102. UE107is served by base station104. UE108is served by base station103.

In one embodiment, wireless communication network100operates with large contiguous radio spectrums. UE101while accessing wireless communication network100, acquires synchronization information and system information using a default bandwidth. Upon detecting the wireless network, UE101can get component carrier configuration (e.g. cell identification) and initial virtual carrier configuration through system information. A virtual carrier (VC) is a block of physically contiguous radio resources within a component carrier. In one embodiment, multiple VCs within a component carrier may share the same cell ID. In another embodiment, multiple VCs within a component carrier may use different cell IDs. When UE101accesses the network, a downlink (DL) common virtual carrier (CVC) is configured to the UE. The DL CVC is used for network entry, idle mode operation, radio resource management (RRM) measurement and data services. The DL CVC has beacon signal (or synchronization signal), system information, common PHY control and reference signal for RRM measurement. The physical location in frequency domain of the CVC can be at the center of a component carrier or any other location of the component carrier. In one embodiment, UE101gets the channel bandwidth of the DL CVC and an offset value of the DL CVC from the central frequency of the component carrier in the system information. There are physical channels and reference signals, such as pilots for demodulation or channel state information measurement, to support the dedicated control and/or data operation. In one embodiment, there is one single DL CVC within a component carrier for UE101. There could be multiple DL CVCs for multiple UEs within one component carrier. An uplink (UL) CVC configuration including the bandwidth and the physical location in frequency domain of the UL CVC is also broadcasted in the system information. There is common PHY control for random access (RACH) in the UL CVC. There are channels and reference signals (e.g. pilots for demodulation or channel state information measurement) to support dedicated PHY control/data operation. In one embodiment, There are channels and reference signals, such as pilots for demodulation or channel state information measurement, to support dedicated PHY control/data operation. In one embodiment, for UE101, there is single uplink CVC within a component carrier. There could be single or multiple uplink CVCs within a component carrier from system aspects.

Besides the DL and UL CVCs that carry control information, one or more DL and UL dedicated VCs (DVCs) are configured for UE101. A DL DVC is used for data services only. In one embodiment, the bandwidth & physical location in frequency domain are configurable by RRC-layer signaling. One or more UL DVCs may also configured for UE101. There is no common PHY control for random access (RACH). There are channels and reference signals, such as pilots for demodulation or channel state information measurement, to support dedicated PHY control/data operation. The dedicated PHY control is used at least for HARQ-ACK, channel state information (CSI) feedback. For both the DL DVC and the UL DVC, the bandwidth & physical location in frequency domain are configurable by RRC-layer signaling.

FIG. 1further shows simplified block diagrams of wireless stations101and base station102in accordance with the current invention.

Base station102has an antenna126, which transmits and receives radio signals. A RF transceiver module123, coupled with the antenna, receives RF signals from antenna126, converts them to baseband signals and sends them to processor122. RF transceiver123also converts received baseband signals from processor122, converts them to RF signals, and sends out to antenna126. Processor122processes the received baseband signals and invokes different functional modules to perform features in base station102. Memory121stores program instructions and data124to control the operations of base station102. Base station102also includes a set of control modules, such as a component carrier (CC) configurator181that configures CCs, a CVC configurator182that configures CVCs, a DVC configurator183that configures DVCs, and a VC reconfiguration handler that reconfigures VCs.

UE101has an antenna135, which transmits and receives radio signals. A RF transceiver module134, coupled with the antenna, receives RF signals from antenna135, converts them to baseband signals and sends them to processor132. RF transceiver134also converts received baseband signals from processor132, converts them to RF signals, and sends out to antenna135. Processor132processes the received baseband signals and invokes different functional modules to perform features in mobile station101. Memory131stores program instructions and data136to control the operations of mobile station101.

UE101also includes a set of control modules that carry out functional tasks. A network entry handler191acquires synchronization and system information with a first channel bandwidth in a wireless network, wherein the first channel bandwidth is a default bandwidth configured by the wireless network, and wherein one or more component carriers is configured. A common virtual carrier handler192configures a DL CVC and a UL CVC, wherein a virtual carrier (VC) is a block of physically contiguous radio resources within a component carrier, and wherein the DL CVC and UL CVC carry common/group-common PHY control information for the UE. A dedicated VC handler193configures one or more DL and UL dedicated virtual carriers (DVCs), wherein the one or more DL and UL DVCs carry data services. A VC switch handler194switches on or off one or more VCs.

The virtual carriers are configured as different types including a DL CVC, a DL DVC, a UL CVC, and a UL DVC. In different embodiments, the different types of virtual carriers may carry different information.FIGS. 2A, 2B, and2C illustrates different configurations for the virtual carriers.

FIG. 2Aillustrates an exemplary diagram of a DVC configured with no common/group-common PHY control information in accordance with embodiments of the current invention.FIG. 2Ashows a component carrier with a bandwidth of X MHz is configured into multiple VCs. A VC203is configured as a DVC. A VC204is configured as a CVC. A VC205is configured as a DVC. In one embodiment, the component carrier may be configured for multiple UEs. As shown, UE201is configured with CVC207, which corresponds to the configured CVC204. UE201is also configured with a DVC206, which corresponds to the configured DVC203. Similarly, UE202is configured with a CVC208, which also corresponds to the configured CVC204. UE202is also configured with a DVC209, which corresponds to the configured DVC205. As shown, DVC205may overlap with CVC204. UE201has CVC and DVC in non-overlapping frequencies while UE202had CVC and DVC in overlapped frequencies. In one embodiment, the CVCs contain the beacon signal (or synchronization signals), the MIB/compact SIB signal, and the common/shared reference signal. In one embodiment, DVC203has no common/group-common PHY control information.

FIG. 2Billustrates an exemplary diagram of a DVC configured with beacon signal (or synchronization signals) and common/shared reference signal information in accordance with embodiments of the current invention. Similar toFIG. 2A, multiple CVC and DVC are configured for the component carrier. Each UE201and202has the same CVC and DVC configuration. In one embodiment, the DVC also contains the beacon signal (or synchronization signals) and the common/shared reference signal.

FIG. 2Cillustrates an exemplary diagram of a DVC configured with common/shared reference signal (or synchronization signals) information in accordance with embodiments of the current invention. Similar toFIG. 2A, multiple CVC and DVC are configured for the component carrier. Each UE201and202has the same CVC and DVC configuration. In one embodiment, the DVC also contains the common/shared reference signal.

FIG. 3illustrates different configures of DL and UL CVCs for a UE in accordance with embodiments of the current invention. In one novel aspect, the UE is configured with a DL CVC and a UL CVC to carry the DL and UL control information, respectively. In one embodiment, the DL CVC and the UL CVC can have the same frequency location within a component carrier for TDD or unpaired spectrum. In another embodiment, the DL CVC and the UL CVC have different frequency locations within a component carrier for TDD or unpaired spectrum are located in different frequency bands for FDD or paired spectrum. A DL CC310is configured with two CVCs, CVC311, and CVC312. A UL CC320is configured with two CVCs, CVC322, and CVC321. As shown, UE301is configured with a DL CVC331corresponding to DL CVC311, and a UL CVC333corresponding to UL CVC321. DL CVC311and UL CVC321have the same frequency location within a component carrier for TDD or unpaired spectrum is located in different frequency bands for FDD or paired spectrum. In another embodiment, UE302is configured with a DL CVC332corresponding to DL CVC312, and a UL CVC334corresponding to UL CVC322. DL CVC312and UL CVC322have the different frequency locations within a component carrier for TDD or unpaired spectrum are located in different frequency bands for FDD or paired spectrum.

The UE configured with VCs may access search spaces, both the common search space and the UE-specific search space differently based on the UE configuration and the VC configurations. In general, the UE in the idle mode, the UE operates with accessing the CVC in the Pcell only. For the UE in a connected mode, the UE can access in a Pcell the CVC only, or both the CVC and the DVC. For a UE in the connected mode, the UE can operate in the Scell with accessing the CVC only, or both the CVC and the DVC, or the DVC only.FIGS. 4A, 4B, and 4Cillustrate different search-space access scheme for UE in the idle and the UE in the connected mode with different primary cell (PCell) and secondary cell (Scell) configuration.

FIG. 4Ashows an exemplary diagram for the UE in the idle mode, operates with accessing the CVC in the Pcell only in accordance with embodiments of the current invention. The UE access a PCell401in the idle mode. The UE accesses the CVC412of the PCell through a configured region of PHY control411. As shown, when the UE accesses DL common VC only within PCell401only, the UE performs the detection for broadcast or UE-specific downlink control information in the common search space of the downlink physical control channel411over the DL common VC412. The UE performs the detection for UE-specific downlink control information in the UE-specific search space, which could be in a different physical location from the common search space, of the downlink physical control channel411over the DL common VC412.

FIG. 4Bshows an exemplary diagram for UE in a connected mode, the UE can access in a CVC and DVC in the PCell in accordance with embodiments of the current invention. The UE access a PCell401in the connected mode. The UE accesses the CVC422and DVC423of the PCell through a configured region of PHY control421of PCell401. As shown, when the UE accesses both DL CVC422and at least one DL DVC423within a primary component carrier401, the UE performs the detection for broadcast or UE-specific downlink control information in the common search space of the downlink control channel over the DL common VC. The UE performs the detection for UE-specific downlink control information in the UE-specific search space of the downlink control channel. In one embodiment, the UE performs the detection for the UE-specific downlink control information in the UE-specific search space over the aggregated radio resources of the DL common VC and all dedicated VC(s). In another embodiment, the UE performs the detection for the UE-specific downlink control information in the UE-specific search space over the aggregated radio resources of all dedicated VC(s).

FIG. 4Cshows an exemplary diagram for UE in a connected mode, the UE can access in a SCell in accordance with embodiments of the current invention. The UE access a PCell401, a SCell402, and a SCell403in the connected mode. The UE accesses the CVC432and DVC433of the PCell through a configured region of PHY control431of PCell401. The UE accesses the CVC435and DVC436of the SCell402through a configured region of PHY control434. The UE accesses the DVC438of the SCell403through a configured region of PHY control437. In one embodiment, when the UE accesses DL CVC435only within a secondary component carrier, the UE performs the detection for UE-specific downlink control information in the UE-specific search space of the downlink physical control channel over the DL common VC. In another embodiment, when the UE accesses both DL CVC435and at least one DL DVC436within a secondary component carrier402, the UE performs the detection for UE-specific downlink control information in the UE-specific search space-1 of the downlink control channel over the DL common VC. The UE performs the detection for UE-specific downlink control information in the UE-specific search space-2 of the downlink control channel over the DL dedicated VC. In one embodiment, the UE performs the detection for UE-specific downlink control information in the UE-specific search space over the aggregated radio resources of the DL common VC and all dedicated VC(s). In another embodiment, the UE performs the detection for UE-specific downlink control information in the UE-specific search space over the aggregated radio resources of all dedicated VC(s). In yet another embodiment, when the UE can access DVC438only within a secondary component carrier403, the UE-specific search space for UE-specific downlink control information (DCI) is defined within the physical DL control channel over the DL dedicated VC(s). In one embodiment, the UE performs UE-specific search space for UE-specific DCI Over the aggregated radio resources of all dedicated VC(s).

FIG. 5illustrates an exemplary flow diagram of the virtual carrier operation procedure in accordance with embodiments of the current invention. At step501, the UE performs network entry. At step502, the UE performs the carrier aggregation (CA) configuration or reconfiguration. At step503, the UE performs the VC configuration or reconfiguration. At step504, the UE performs component carrier (CC) activation. At step505, the UE performs VC switch on or switch off operation. At step506, the UE performs data transmission on the configured VCs. At step507, the UE performs RRM measurements on the VCs. At step508, the UE deactivates the CC.

FIG. 6illustrates an exemplary flow diagram of the network entry and virtual carrier configuration procedure in accordance with embodiments of the current invention. At step601, the UE acquires synchronization and system information with a default bandwidth of Y MHz. In one embodiment for a PCell using NRAI anchor, with 60 Khz subcarrier space, Y=20 MHz. In one embodiment, for the NRAI anchor, beacon signal (or synchronization signals) and MIB or compact SIB is used. At step611, the UE obtains a central frequency offset value for the DL CVC. In one embodiment, the offset value is broadcasted in the system information. At step612, the UE obtains the channel bandwidth for the DL CVC and the UL CVC. In one embodiment, the value of the channel bandwidth can be adjusted based on predefined criteria. In one embodiment, the predefined criterion is the load of the idle-mode UEs. It is applied for the following procedures on DL/UL CVC of Pcell, e.g. RACH for RRC-layer connection, UE capability negotiation, and RRC-layer configuration. At step613, the UE obtains the physical location for the UL CVC. At step620, the UE obtains DL and/or UL DVC configuration for each CC. In one embodiment, the DVC configuration is obtained through RRC-layer signaling on the PCell. The DVC configuration includes all potential DVCs for a component carrier. DVC configuration should include at least physical location & bandwidth of each DVC for a component carrier. The DVC configuration can be signaled together with CA configuration. In another embodiment, the DVC configuration is obtained through MAC CE. The DVC reconfiguration is transmitted on PCell. At step630, the UE obtains new DL and/or UL CVC configuration. In one embodiment, when the configuration of DL/UL CVC is changed, UE can obtain new configuration of DL/UL CVC via RRC-layer signaling on Pcell without receiving updated system information.

FIG. 7illustrates an exemplary flow diagram of virtual carrier switch-on/off procedure in accordance with embodiments of the current invention. At step701, the UE receives VC switch on/off command. In one embodiment, the VC switch command is received via MAC signaling at step710. The MAC signaling includes at least a bitmap indicating all potential VC configurations signaled by RRC-layer signaling. The UE receives the switch command in subframe (or slot) N at step711. The UE monitors the dedicated MAC control in subframe (or slot) N+K, wherein the K is predefined constant integer. In one embodiment, a single dedicated PHY control to schedule data transmission over the aggregated data region of all switched-on DL VCs on a component carrier. The UE always obtains common PHY control on DL CVC of PCell.

In another embodiment, the VC switch command is received via PHY signaling at step720. In one embodiment, the PHY signaling consists of at least a bitmap indicating all potential VC configurations signaled by RRC-layer signaling. The UE receives the switch command in subframe (or slot) N at step711. The UE monitors the dedicated PHY control in subframe (or slot) N+K, wherein the K is predefined constant integer. In one embodiment, a single dedicated PHY control to schedule data transmission over the aggregated data region of all switched-on DL VCs on a component carrier. The UE always obtains common PHY control on DL CVC of PCell.

FIG. 8illustrates an exemplary flow diagram of UE triggered UL VC switch command in accordance with embodiments of the current invention. At step801, the UE transmit triggering signal via dedicated PHY, MAC or RRC-layer signaling (step831), including at least one of the following information: Buffer status report for UL, Requested UL bandwidth, Requested UL resources, and UE identification (step832). At step810, the UE receives UL VC configuration switch command from the network after transmitting the triggering signal. At step820, the UE performs switch on/off operation based on the received switch command from the network.

FIG. 9illustrates an exemplary flow diagram of the RRM measurement for virtual carriers in accordance with embodiments of the current invention. At step901, the UE starts the RRM measurement in the VC operation. At step910, the UE determines whether only the DL DVC is switched-on. If step910determines yes, the UE performs RRM measurement on the CVC with a gap. It implies UE does not have the capability to monitor PHY control on both DL CVC and DL DVC at the same time. The UE monitors PHY control on DL DVC and switch its center frequency back to DL CVC during the configured measurement gap for RRM measurement periodically. If step910determines no, the UE performs RRM measurement on the CVC without a gap. It implies UE has the capability to monitor PHY control on both DL CVC and DL DVC at the same time.

FIG. 10shows an exemplary flow chart of the UE performing network entry and VC configuration in a VC operation in accordance with embodiments of the current invention. At step1001, the UE receives a configuration of one or more virtual carriers (VCs) in a wireless network, wherein the UE is configured with one or more component carriers, and wherein a virtual carrier is a block of physically contiguous radio resources within a component carrier configured for the UE, and wherein virtual carriers within a component carrier may overlap with each other in frequency domain. At step1002, the UE receives a signal to switch from a set of virtual carriers to another set of virtual carriers for data reception/transmission on corresponding one or more activated component carriers.

FIG. 11shows an exemplary flow chart of the UE performing VC switch command in a VC operation in accordance with embodiments of the current invention. At step1101, the UE configures one or more component carriers in a wireless network. At step1102, the UE configures a downlink (DL) common virtual carrier (CVC) and an uplink (UL) CVC, wherein a virtual carrier (VC) is a block of physically contiguous radio resources within a component carrier, and wherein the DL CVC and UL CVC carry control information for the UE. At step1103, the UE configures one or more DL and UL dedicated virtual carriers (DVCs), wherein the one or more DL and UL DVCs carry data services. At step1104, the UE reconfigures one or more configured VCs.