Framework for coordinated multipoint transmission based on a multicell MAC/RRC design

Briefly, in accordance with one or more embodiments, two or more cells are configured to perform coordinated multipoint (CoMP) transmission for one or more user equipment devices with a common media access control (MAC) or a common radio resource control (RRC). Measurement information is received from the one or more user equipment devices. One or more of the cells may be deactivated, or one or more additional cells may be activated for coordinated multipoint transmission based at least in part on the measurement information.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional Application No. 61/389,080 (P36288Z) filed Oct. 1, 2010. Said Application No. 61/389,080 is hereby incorporated herein in its entirety.

BACKGROUND

Coordinated Multi-Point (CoMP) is a technique that may be utilized to increase the performance of Fourth Generation (4G) wireless communication systems. Coordinated multipoint transmission may be utilized to increase throughput and service quality in wireless networks, particularly at or near the edge of a given cell in a cellular network. In contrast to carrier aggregation (CA) techniques which combine transmissions from two different carriers operating on two different frequencies to increase data rates, coordinated multipoint transmission involves using two carriers operating on the same frequency. Although CoMP has been proposed for 4G wireless communications, a consistent framework to define, activate, and schedule multiple cells to support CoMP transmission has yet to be defined.

It will be appreciated that for simplicity and/or clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, if considered appropriate, reference numerals have been repeated among the figures to indicate corresponding and/or analogous elements.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are set forth to provide a thorough understanding of claimed subject matter. However, it will be understood by those skilled in the art that claimed subject matter may be practiced without these specific details. In other instances, well-known methods, procedures, components and/or circuits have not been described in detail.

In the following description and/or claims, the terms coupled and/or connected, along with their derivatives, may be used. In particular embodiments, connected may be used to indicate that two or more elements are in direct physical and/or electrical contact with each other. Coupled may mean that two or more elements are in direct physical and/or electrical contact. However, coupled may also mean that two or more elements may not be in direct contact with each other, but yet may still cooperate and/or interact with each other. For example, “coupled” may mean that two or more elements do not contact each other but are indirectly joined together via another element or intermediate elements. Finally, the terms “on,” “overlying,” and “over” may be used in the following description and claims. “On,” “overlying,” and “over” may be used to indicate that two or more elements are in direct physical contact with each other. However, “over” may also mean that two or more elements are not in direct contact with each other. For example, “over” may mean that one element is above another element but not contact each other and may have another element or elements in between the two elements. Furthermore, the term “and/or” may mean “and”, it may mean “or”, it may mean “exclusive-or”, it may mean “one”, it may mean “some, but not all”, it may mean “neither”, and/or it may mean “both”, although the scope of claimed subject matter is not limited in this respect. In the following description and/or claims, the terms “comprise” and “include,” along with their derivatives, may be used and are intended as synonyms for each other.

Referring now toFIG. 1, a diagram of an enhanced Node B (eNB) serving multiple sectors of multiple cells and capable of implementing coordinated multipoint (CoMP) transmission in accordance with one or more embodiments will be discussed. As shown inFIG. 1, wireless communication network100may include an enhanced Node B (eNB) device110that may serve multiple sectors such as sector112, sector114, and sector116in respective cells, cell0, cell1, and cell2, of a cellular communication system. In one or more embodiments, enhanced Node B110may be part of a Third Generation (3G) or Fourth Generation (4G) communication system in accordance with a Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) standard. Alternatively, in some embodiments eNB110may be part of an Institute of Electrical Engineers (IEEE) IEEE 802.16 standard such as IEEE 802.16e or IEEE 802.16m standard to implement a Worldwide Interoperability for Microwave Access (WiMAX) network or a WiMAX-II standard, although the scope of the claimed subject matter is not limited in this respect. Although network100may be discussed with respect to a given standard, the claimed subject matter is not limited to any particular standard, or release or version of that standard, and may encompass further versions or releases of those standards including standards not yet in existence but which may come into existence in the future.

In a given sector114, eNB may implement intra-eNB coordinated multipoint transmission (CoMP) wherein a single eNB110controls the CoMP operation. In such embodiments, one or more remote radio elements (RRE), also known as a remote radio unit (RRU), may be deployed within a single sector such as RRE118and RRE120deployed in sector114as shown inFIG. 1. The RREs may include radio-frequency (RF) circuits to enhance the coverage, throughput and/or link quality of eNB110, for example to implement coordinated multipoint (CoMP) transmission and/or carrier aggregation. In such a network100, one or more user equipment (UE) devices such as UE122, UE124, and/or UE126may communicate with eNB110and/or one or more of RRE118or RRE120. In one or more embodiments, CoMP may be implemented wherein a common or shared media access control (MAC) and radio resource control (RRC) manage multiple physical (PHY) devices or cells such as RRE118and RRE120operating on the same frequency. Intra-eNB CoMP allows joint processing and beam forming across multiple cells, such as the RREs) within a single eNB. The cells may be implemented via different antenna orientations of the eNB to serve different sectors of the same cell site where eNB110is located, or alternatively the cells may be implemented via one or more remote radio elements such as RRE118and RRE120to provide local coverage within a given sector114. Using multiple RREs may be referred to a distributed antenna system (DAS) deployment. An example of a framework of a common MAC/RRC controlling CoMP operation is shown in and described with respect toFIG. 2, below.

Referring now toFIG. 2, a block diagram of a framework to implement intra-eNB CoMP under the same radio resource control (RRC) with joint media access control (MAC) in accordance with one or more embodiments in accordance with one or more embodiments will be discussed. As shown inFIG. 2, framework200for implementing intra-eNB CoMP may comprise radio resource control (RRC)210and media access control (MAC)212to control multiple physical (PHY) devices represented as PHY-A214, PHY-B216, and/or PHY-C218. AlthoughFIG. 2shows three physical devices for purposes of example, any number of physical devices may be implemented, and the scope of the claimed subject matter is not limited in this respect. As shown inFIG. 2, PHY-A214may operate on a first frequency (RF1), PHY-B216may also operate on the first frequency (RF1), and PHY-C218may operate on a second frequency (RF2). Where user equipment such as UE122communicates with both PHY-A214and PHY-B216both operating on the same frequency (RF1), coordinated multipoint (CoMP) may be implemented. Where user equipment such as UE124communicates with both PHY-B216and PHY-C218each operating on a different frequency, (RF1) and (RF2), respectively, carrier aggregation (CA) may be implemented.

In one or more embodiments, under framework200, Per UE configuration and management of multiple Intra-eNB cells, which may be realized as sectors or RREs, may be controlled by an eNB under the same RRC210with joint MAC212operation. In one or more embodiments, such Intra-eNB cells may be distinguished by user equipment (UE) devices by their respective PHY layer cell identifications (Cell-IDs) for example as defined in the Long Term Evolution (LTE) standard Release 8, Release 9, and/or Release 10. Such a framework200may be utilized for scenarios in which multiple RREs are deployed with common Cell-IDs but with different PHY attributes, for example for example CSI-RS pattern, antenna port assignments, etc. as defined in a secondary cell configuration phase that is defined with respect toFIG. 5andFIG. 6, below.

Referring now toFIG. 3andFIG. 4, block diagrams of a control plane and a data plane, respectively, for implementing coordinated multipoint transmission in accordance with one or more embodiments will be discussed. As shown inFIG. 3, control plane300comprises UE122coupled with eNB110and media management entity (MME)338, wherein UE122comprises radio resource control (RRC) block312, packet data convergence protocol (PDCP) block316, radio link control (RLC) block318, media access control (MAC) block320, and physical layer (PHY) blocks PHY322and PHY324. The eNB110likewise comprises RRC block326, PDCP block328, RLC block330, MAC block332, and PHY block PHY334and PHY336coupled to respective blocks of the UE122. Furthermore, UE122includes NAS block310coupled to non-access stratum (NAS) block340of mobility management entity (MME)338. Similarly, as shown inFIG. 4, data plane400comprises UE122coupled with eNB110, wherein UE122comprises PDCP block316, RLC block318, MAC block320, PHY block322and PHY block324. The eNB110likewise comprises PDCP block328, RLC block330, MAC block332, PHY block334and PHY block336coupled to respective blocks of the UE122.

Referring now toFIG. 5, a flow diagram of a method to configure coordinated multipoint cells for a UE in accordance with one or more embodiments will be discussed. As shown inFIG. 5, method500may include more or fewer blocks, and/or in one or more alternative orders, than shown, and the scope of the claimed subject matter is not limited in these respects. For coordinated multipoint (CoMP), a primary cell may be selected by the eNB, and the user equipment such as UE122may be configured by the primary cell with additional cells on the same frequency. At block510, UE122measures the frequencies on which the cells are operating. If the frequencies are the same as determined at block512, then CoMP may be utilized. At block518, UE122performs radio resource measurement (RRM) measurements on the secondary cells and feeds back the measurement information to the eNB110to further assist with CoMP operation. The eNB then activates or deactivates the secondary cells at block520for CoMP based at least in part on the RRM measurements obtained by the UE122. In one or more embodiments, the measurements provided by the UE122and the feedback channels on the primary cell may be consistent with a similar approach as implemented with carrier aggregation techniques. At block522, the primary cell provides cross carrier and cell downlink scheduling and control information which may also be consistent with a similar approach as implemented with carrier aggregation techniques. In one or more embodiments, the RRM measurements to support CoMP may not require an additional extension or extensions to the single carrier, non-CoMP communication arrangement. The RRM measurements may be set thresholds for which a cell may be eligible or ineligible for CoMP operation. Furthermore, in one or more embodiments, the primary cell may change based at least in part on the RRM measurements. For example, depending on how transparent a secondary cell or another cell may appear to the UE122, such a primary cell change may either be a standard cell handover or specifically a primary cell change. Such transparency may refer to how the secondary cell or another cell operates in CoMP mode versus how it operates in a regular mode, for example whether the UE122will get the channel state indicator (CSI) for that cell operating under CoMP, and whether the UE122performs explicit PHY feedback for the cell. In the event those conditions are true, then a primary cell change for CoMP may be viable, and a future primary cell change for carrier aggregation may apply as well to intra-eNB CoMP.

Referring now toFIG. 6, a flow diagram of a method to configure secondary cells for coordinated in accordance with one or more embodiments will be discussed. As shown inFIG. 6, method600may include more or fewer blocks, and/or in one or more alternative orders, than shown, and the scope of the claimed subject matter is not limited in these respects. In one or more embodiments, blocks610,612, and614may be performed in the downlink (DL), and blocks616and618may be performed in the uplink (UL). For the downlink, at block610, the primary cell provides information about the configuring cell (the primary cell) to the secondary cells. Such information may include the number of cells being coordinated for CoMP, the cell identifications (Cell IDs), the number of antenna ports per each eNB, and so on. At block612, the primary cell configures channel state information reference signals (CSI-RS) on the secondary cells, including subframe offset, duty cycle, the location of the CSI-RS within the downlink subframe, and so on. At block614, the primary cell configures the uplink control channels for CoMP operation, including providing the feedback format, duty cycle, and so on. For the uplink, at block616the secondary cells provide feedback to the primary cell to support the CoMP mode of operation, including a precoding matrix index (PMI), channel quality indicator (CQI), rank indicator (RI), and so on.

In one or more embodiments, the measurement of the channels is performed by using channel state indicator (CSI) reference signals transmitted by the primary cell and secondary cells on different RREs. The CSI-RS configuration (duty cycle, subframe offset and intra-subframe location) of both cells will be provided by radio resource control (RRC) signaling of the primary cell. Furthermore, PDSCH muting may also be applied on the primary cell to enhance the channel measurements performance from the secondary cell. The UE122will also report feedback to the primary cell only, as indicated at block618. In order to minimize the impact to the standard specification and simplify UE implementation for coordinated beamforming CoMP, feedback channels may be reused as specified in LTE Releases 8 through 10 which are based on PMI, CQI, and RI reports. In one or more embodiments, one modification to the present LTE Releases may include periodically replacing regular feedback information with feedback information related to CoMP operation, although the scope of the claimed subject matter is not limited in this respect. Furthermore, although Intra-eNB CoMP is discussed herein for purposes of example, in one or more embodiments the MAC212and RRC210control of CoMP ofFIG. 2may likewise be extended to implement Inter-eNB CoMP wherein multiple eNBs may operating on the same frequency may provide CoMP services to one or more UEs. Such an arrangement may involve modification of the inter-eNB interface and coordination between the eNBs, although the scope of the claimed subject matter is not limited in this respect.

Referring now toFIG. 7, a block diagram of an information handling system capable of utilizing coordinated multipoint transmission in accordance with one or more embodiments will be discussed. Information handling system700ofFIG. 7may tangibly embody one or more of any of the network elements of network100as shown in and described with respect toFIG. 1. For example, information handling system500may represent the hardware of enhanced Node B110, RRE118, and/or user equipment122, with greater or fewer components depending on the hardware specifications of the particular device or network element. Although information handling system700represents one example of several types of computing platforms, information handling system700may include more or fewer elements and/or different arrangements of elements than shown inFIG. 7, and the scope of the claimed subject matter is not limited in these respects.

Information handling system700may comprise one or more processors such as processor710and/or processor712, which may comprise one or more processing cores. One or more of processor710and/or processor712may couple to one or more memories716and/or718via memory bridge714, which may be disposed external to processors710and/or712, or alternatively at least partially disposed within one or more of processors710and/or712. Memory716and/or memory718may comprise various types of semiconductor based memory, for example volatile type memory and/or non-volatile type memory. Memory bridge714may couple to a graphics system720to drive a display device (not shown) coupled to information handling system700.

Information handling system700may further comprise input/output (I/O) bridge722to couple to various types of I/O systems. I/O system724may comprise, for example, a universal serial bus (USB) type system, an IEEE 1394 type system, or the like, to couple one or more peripheral devices to information handling system700. Bus system726may comprise one or more bus systems such as a peripheral component interconnect (PCI) express type bus or the like, to connect one or more peripheral devices to information handling system700. A hard disk drive (HDD) controller system728may couple one or more hard disk drives or the like to information handling system, for example Serial ATA type drives or the like, or alternatively a semiconductor based drive comprising flash memory, phase change, and/or chalcogenide type memory or the like. Switch730may be utilized to couple one or more switched devices to I/O bridge722, for example Gigabit Ethernet type devices or the like. Furthermore, as shown inFIG. 7, information handling system700may include a radio-frequency (RF) block732comprising RF circuits and devices for wireless communication with other wireless communication devices and/or via wireless networks such as network100ofFIG. 1, for example where information handling system700embodies eNB110, RRE118, and/or user equipment122, although the scope of the claimed subject matter is not limited in this respect.

Although the claimed subject matter has been described with a certain degree of particularity, it should be recognized that elements thereof may be altered by persons skilled in the art without departing from the spirit and/or scope of claimed subject matter. It is believed that the subject matter pertaining to coordinated multipoint transmission based on a multicell MAC/RRC design and/or many of its attendant utilities will be understood by the forgoing description, and it will be apparent that various changes may be made in the form, construction and/or arrangement of the components thereof without departing from the scope and/or spirit of the claimed subject matter or without sacrificing all of its material advantages, the form herein before described being merely an explanatory embodiment thereof, and/or further without providing substantial change thereto. It is the intention of the claims to encompass and/or include such changes.