Inter-eNode B handover procedure

Methodologies are described that facilitate inter-eNode B handover. In various embodiments, logical protocol termination can be implemented between the user equipment and the target eNode B for inter-eNode B handover signaling. The provided handover forwarding and encapsulation mechanisms enable improved inter-operability between eNode Bs implementing different protocol versions or from different vendors, which in turn enables frequent protocol upgrades. Additionally, the invention enables the target eNode B to implement new radio configurations even if the configuration is unsupported by the source eNode B.

BACKGROUND

The following description relates generally to wireless communications, and more particularly to mechanisms for inter-eNode B (eNB) handover.

Wireless communication systems are widely deployed to provide various types of communication; for instance, voice and/or data may be provided via such wireless communication systems. A typical wireless communication system, or network, can provide multiple users access to one or more shared resources. For instance, these systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., bandwidth and transmit power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) systems, and orthogonal frequency division multiple access (OFDMA) systems.

Generally, a wireless multiple-access communication system can support simultaneous communication for multiple wireless terminals. Each terminal communicates with one or more base stations via transmissions on the forward and reverse links. The forward link (or downlink (DL)) refers to the communication link from the base stations to the terminals, and the reverse link (or uplink (UL)) refers to the communication link from the terminals to the base stations. Such communication links can be established via a single-in-single-out, multiple-in-single-out or a multiple-in-multiple-out (MIMO) system.

A MIMO system employs multiple (NT) transmit antennas and multiple (NR) receive antennas for data transmission. A MIMO channel formed by the NTtransmit and NRreceive antennas may be decomposed into NSindependent channels, which are also referred to as spatial channels, where NS≦min{NT, NR}. Each of the NSindependent channels corresponds to a dimension. The MIMO system can provide improved performance (e.g., higher throughput and/or greater reliability) if the additional dimensionalities created by the multiple transmit and receive antennas are utilized. A MIMO system can support time division duplex (TDD) and frequency division duplex (FDD) systems. In a TDD system, the forward and reverse link transmissions are on the same frequency region so that the reciprocity principle allows the estimation of the forward link channel from the reverse link channel. This enables the access point to extract transmit beamforming gain on the forward link when multiple antennas are available at the access point.

In cellular wireless systems, a service area is divided into a number of coverage zones generally referred to as cells. Each cell may be further subdivided into a number of sectors served by a number of base stations. While each sector is typically depicted as a distinct geographical area, sectors typically provide overlapping signal coverage to provide seamless communication as wireless terminals or user equipment (UE) transit from a cell to an adjacent cell. For example, when a mobile user passes between cells, there must be efficient communications handover or handoff between base stations to provide a seamless mobile internet experience to the user. Without an efficient mechanism to hand-off mobile users between cells, the user would experience service interruptions and delays, lost transmissions, or dropped calls.

A handoff, or handover (HO), is the process in which a UE (e.g., a wireless phone) is handed from one cell to the next in order to maintain a radio connection with the network. The variables that dictate a handover depend on the type of cellular system. For example, in CDMA systems interference requirements are the limiting factor for handover. In FDMA and TDMA systems such as the Global System for Mobile communications (GSM), the main limiting factor is the signal quality available to the UE.

One form of handover or handoff is when a UE call in progress is redirected from its current cell (e.g., the source cell) and channel to a new cell (e.g., the target cell) and channel. In terrestrial networks, the source and the target cells may be served from two different cell sites or from two different sectors of the same cell site. The former is called an inter-cell handover, where the latter refers to a handover within one sector or between different sectors of the same cell (e.g., an intra-cell handover). Generally, the purpose of inter-cell handover is to maintain the call as the subscriber is moving out of the area covered by the source cell and entering the area of the target cell.

As an example, during a call, one or more parameters of the signal in the channel in the source cell are monitored and assessed in order to decide when a handoff may be necessary (e.g., the DL and/or UL may be monitored). Typically, the handoff may be requested by the UE or by the base station of its source cell and, in some systems, by a base station of a neighboring cell. The phone and the base stations of the neighboring cells monitor each other others' signals and the best target candidates are selected among the neighboring cells.

For example, Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN) contains base stations (e.g., Node Bs), and Radio Network Controllers (RNC). The RNC provides control functionalities for one or more Node Bs and carries out Radio Resource Management (RRM), some of the mobility management functions, and is the point where encryption is done before user data is sent to and from the mobile. A Node B and an RNC can be the same device, although typical implementations have a separate RNC located in a central office serving multiple Node B's. The RNC and its corresponding Node Bs are called the Radio Network Subsystem (RNS). There can be more than one RNS present in an UTRAN. The UE requires a Radio Resource Control (RRC) connection to access the services of the UMTS network, which is a point to point bi directional connection between the RRC entities on the UE and UTRAN (e.g., the RRC is terminated in the UTRAN). Typically the UMTS handover mechanism (e.g., measurement, decision, and execution) is centrally controlled where the RNC is responsible for handover decisions, requiring handover signaling to the UE, and requiring complicated coordination via 3-way handshake (Measurement Report, Handover Command (HO Command), and HO Complete) among the network components.

One problem in connection with such a mechanism is that interoperability issues with deploying UTRAN equipment from different vendor have generally hindered mobile operators' attempts to deploy multi-vendor networks. In addition, interoperability issues with different RRC protocol versions limits opportunities for mobile operators to implement protocol upgrades.

In Evolved Universal Terrestrial Radio Access Network (E-UTRAN), RRM is more distributed than that of UTRAN by implementing RRM functions at the evolved Node B (eNode B) level. As a result, there is increased likelihood that due to protocol mismatches, new radio configurations will not be used in the target eNode B due to lack of support from a source eNode B. The current working assumption for the handover signaling for LTE is to have the same 3-way handshake (e.g., Measurement Report, HO command and HO Complete) as in UMTS, with the above identified difficulties anticipated. In addition to solving these problems, further improvements are desired in connection with inter-eNode B (eNB) handover procedure to allow mobile operators to benefit from frequent protocol upgrades, including physical layer upgrades, allow mobile operators to aggressively employ multi-vendor networks, and enable new radio configurations usage in the target eNode B despite lack of protocol support from the source eNode B.

SUMMARY

In accordance with one or more embodiments and corresponding disclosure thereof, various aspects are described in connection with facilitating inter-eNode B handover. As described above, E-UTRAN implements a number of radio resource management function functions at eNode B level. The current working assumption for handover signaling is to use the same 3-way handshake as in UMTS, with the above identified difficulties, where the UMTS handover mechanism (e.g., measurement, decision, and execution) is centrally controlled. However, significant architectural differences exists, such that protocol optimizations can be implemented to allow mobile operators to benefit from frequent protocol upgrades (including physical layer upgrades), allow mobile operators to aggressively employ multi-vendor networks, and enable new radio configurations usage in the target eNode B despite lack of protocol support from the source eNode B.

In accordance with various non-limiting embodiments, the invention provides architectural and protocol changes for inter-node handover procedure. According to various aspects of the invention, logical protocol termination can be implemented between the UE and the target eNB for inter-eNB HO signaling. Advantageously, protocol termination between UE and the target eNB enables elimination of the UMTS HO Complete message for LTE, which allows for relatively more simple protocol implementations. According to further aspects of the invention, a Measurement Report message and a HO Command message can be forwarded to the target node and the UE respectively by the source node.

According to further non-limiting embodiments, the HO Command message can be encapsulated into an appropriate RRC message (e.g., a RRC direct transfer) by the source eNB. Advantageously, the source eNB does not require the ability to understand all the contents in the HO Command message. Thus, source eNB can minimally require only the ability to identify the HO Command message as a HO Command message, according to various embodiments. In further embodiments, the source eNB can include the ability to discern the HO Command message destination. Advantageously, the forwarding mechanism of the present invention does not require the relatively more complicated coordination mechanism between the source BS and the target BS of UMTS, which may be challenging in the multi-vendor network. As will be appreciated, the provided handover forwarding and encapsulation mechanisms enable improved inter-operability between eNode Bs implementing different protocol versions or from different vendors, which in tum enables frequent protocol upgrades. Additionally, the invention enables the target eNode Bs to implement new radio configurations even if the configuration is unsupported by the source eNode B.

To the foregoing and related ends, various methods that facilitate inter-eNode B handover are described herein. One method can comprise receiving and encapsulating, by a source node, a handover command message created by a target node into a Radio Resource Control message. Further, the method can include enciphering an encapsulated handover command message based on a pre-existing security association between a UE associated with the handover command message and the source node. Advantageously, the method does not require a new security association between the UE and the target node. For example, an existing security association can be provided by any one or more of existing radio interface layers, sublayers, protocols, and/or the like, or any combination thereof (e.g., Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), etc.). The method can further include transmitting the encapsulated handover command message to the wireless terminal. Additionally, the method can include applying integrity protection on the encapsulated handover command message by a source node (e.g., a Radio Resource Control (RRC) of the source node).

In a related embodiment of the invention, a method can comprise receiving and processing measurement report information by a target base station. Additionally, the method can include determining, by the target base station, a handover decision concerning a mobile device associated with the measurement report information, and transmitting a handover command to the mobile device, wherein the handover command includes supplemental information to facilitate generating the handover complete indicator in the wireless communication system.

In yet another embodiment, a method is provided for inter-node transfer in a wireless communication system that comprises transmitting, by a mobile device, a measurement report message to a source node for source node encapsulation into an inter-node message (e.g., an inter-eNodeB message) and forwarding to a target node, and receiving, by the mobile device, a source node encapsulated handover command message forwarded from the target node.

A further embodiment of the invention relates to a communications apparatus. The communications apparatus can include a memory that retains instructions for receiving and encapsulating HO Commands from target nodes. Additionally, the memory can further retain instructions for enciphering and transmitting a handover command to the UE. Further, the communications apparatus can include a processor, coupled to the memory, configured to execute the instructions retained in the memory.

In a related embodiment, a communications apparatus can include a memory that retains instructions for receiving and processing, by a target node, a measurement report message. The memory can further retain instructions for determining, by the target node, a handover decision concerning a wireless terminal associated with the measurement report message. Further, the communications apparatus can include a processor, coupled to the memory, configured to execute the instructions retained in the memory.

Still other embodiments relate to a machine-readable media having stored thereon machine-executable instructions for performing various embodiments of the invention described herein. In other embodiments of the invention, an apparatus in a wireless communication system can include a processor, wherein the processor can be configured to perform the various embodiments of the invention described herein.

DETAILED DESCRIPTION

In addition, various aspects of the present invention are described below. It should be apparent that the teaching herein may be embodied in a wide variety of forms and that any specific structure and/or function disclosed herein is merely representative. Based on the teachings herein, one skilled in the art should appreciate that an aspect disclosed herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented and/or a method practiced using any number of the aspects set forth herein. In addition, an apparatus may be implemented and/or a method practiced using other structure and/or functionality in addition to or other than one or more of the aspects set forth herein. As an example, many of the methods, devices, systems and apparatuses described herein are described in the context of inter-eNode B handover in E-UTRAN communications systems. One skilled in the art should appreciate that similar techniques could apply to other communication environments.

As used in this application, the terms “component,” “module,” “system,” and the like are intended to refer to a computer-related entity, either hardware, firmware, a combination of hardware and software, software, software in execution, firmware, middle ware, microcode, and/or any combination thereof. For example, a component can be, but is not limited to being, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, not limitation, both an application running on a computing device and the computing device can be a component. One or more components can reside within a process and/or thread of execution and a component can be localized on one computer and/or distributed between two or more computers. In addition, these components can execute from various computer readable media having various data structures stored thereon. The components may communicate by way of local and/or remote processes such as in accordance with a signal having one or more data packets (e.g., data from one component interacting with another component in a local system, distributed system, and/or across a network such as the Internet with other systems by way of the signal). Additionally, components of systems described herein may be rearranged and/or complemented by additional components in order to facilitate achieving the various aspects, goals, advantages, etc., described with regard thereto, and are not limited to the precise configurations set forth in a given figure, as will be appreciated by one skilled in the art.

Furthermore, various embodiments are described herein in connection with a wireless terminal or user equipment (UE). A wireless terminal or UE can also be called a system, subscriber unit, subscriber station, mobile station, mobile, mobile device, remote station, remote terminal, access terminal, user terminal, terminal, wireless communication device, user agent, or user device. A wireless terminal or UE can be a cellular telephone, a cordless telephone, a Session Initiation Protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device having wireless connection capability, computing device, or other processing device connected to a wireless modem. Moreover, various embodiments are described herein in connection with a base station. A base station can be utilized for communicating with wireless terminal(s) and can also be referred to as an access point, Node B, e-Node B, source or target nodes, or some other terminology.

Moreover, various aspects or features described herein can be implemented as a method, apparatus, or article of manufacture using standard programming and/or engineering techniques. The term “article of manufacture” as used herein is intended to encompass a computer program accessible from any computer-readable device, carrier, or media. For example, computer-readable media can include but are not limited to magnetic storage devices (e.g., hard disk, floppy disk, magnetic strips, etc.), optical disks (e.g., compact disk (CD), digital versatile disk (DVD), etc.), smart cards, and flash memory devices (e.g., EPROM, card, stick, key drive, etc.). Additionally, various storage media described herein can represent one or more devices and/or other machine-readable media for storing information. Additionally it should be appreciated that a carrier wave can be employed to carry computer-readable electronic data or instructions such as those used in transmitting and receiving voice mail, in accessing a network such as a cellular network, or in instructing a device to perform a specified function. Of course, those skilled in the art will recognize many modifications may be made to the disclosed embodiments without departing from the scope or spirit of the invention as described and claimed herein.

Referring now toFIG. 1, a multiple access wireless communication system according to one embodiment is illustrated. Access point100(AP) includes multiple antenna groups, one including104and106, another including108and110, and an additional including112and114. InFIG. 1, only two antennas are shown for each antenna group, however, more or fewer antennas may be utilized for each antenna group. Access terminal116(AT) is in communication with antennas112and114, where antennas112and114transmit information to access terminal116over forward link120and receive information from access terminal116over reverse link118. Access terminal122is in communication with antennas106and108, where antennas106and108transmit information to access terminal122over forward link126and receive information from access terminal122over reverse link124. In a FDD system, communication links118,120,124and126may use different frequency for communication. For example, forward link120may use a different frequency than that used by reverse link118.

Each group of antennas and/or the area in which they are designed to communicate is often referred to as a sector of the access point. In the embodiment, antenna groups each are designed to communicate to access terminals in a sector of the areas covered by access point100.

In communication over forward links120and126, the transmitting antennas of access point100utilize beamforming in order to improve the signal-to-noise ratio of forward links for the different access terminals116and124. Also, an access point using beamforming to transmit to access terminals scattered randomly through its coverage causes less interference to access terminals in neighboring cells than an access point transmitting through a single antenna to all its access terminals.

FIG. 2illustrates a wireless communication system200with multiple base stations210and multiple terminals220as may be utilized in conjunction with one or more aspects of the present invention. A base station is generally a fixed station that communicates with the terminals and may also be called an access point, a Node B, e-Node B, or some other terminology. Each base station210provides communication coverage for a particular geographic area, illustrated as three geographic areas, labeled202a,202b, and202c. The term “cell” can refer to a base station and/or its coverage area depending on the context in which the term is used. To improve system capacity, a base station coverage area may be partitioned into multiple smaller areas (e.g., three smaller areas, according to cell202ainFIG. 2),204a,204b, and204c. Each smaller area can be served by a respective base transceiver subsystem (BTS). The term “sector” can refer to a BTS and/or its coverage area depending on the context in which the term is used. For a sectorized cell, the BTSs for all sectors of that cell are typically co-located within the base station for the cell. The transmission techniques described herein may be used for a system with sectorized cells as well as a system with un-sectorized cells. For simplicity, in the following description, the term “base station” is used generically for a fixed station that serves a sector as well as a fixed station that serves a cell.

Terminals220are typically dispersed throughout the system, and each terminal may be fixed or mobile. A terminal may also be called an access terminal, user equipment (UE), a wireless communication device, a mobile station, a user device, or some other terminology. A terminal may be a wireless device, a cellular phone, a personal digital assistant (PDA), a wireless modem card, and so on. Each terminal220may communicate with zero, one, or multiple base stations on the downlink and uplink at any given moment. The downlink (or forward link) refers to the communication link from the base stations to the terminals, and the uplink (or reverse link) refers to the communication link from the terminals to the base stations.

For a centralized architecture, a system controller230couples to base stations210and provides coordination and control for base stations210. For a distributed architecture, base stations210may communicate with one another as needed. Data transmission on the forward link occurs from one access point to one access terminal at or near the maximum data rate that can be supported by the forward link and/or the communication system. Additional channels of the forward link (e.g., control channel) may be transmitted from multiple access points to one access terminal. Reverse link data communication may occur from one access terminal to one or more access points via one or more antennas at the terminals220and or at the base stations210, as described above with respect toFIG. 1.

As described above, E-UTRAN implements a number of radio resource management function functions at eNode B level. The current working assumption for handover signaling is to use the same 3-way handshake as in UMTS, with the above identified difficulties, where the UMTS handover mechanism (e.g., measurement, decision, and execution) is centrally controlled. However, significant architectural differences exists, such that protocol optimizations can be implemented to allow mobile operators to benefit from frequent protocol upgrades (including physical layer upgrades), allow mobile operators to aggressively employ multi-vendor networks, and enable new radio configurations usage in the target eNode B despite lack of protocol support from the source eNode B.

FIG. 3Aillustrates a non-limiting high-level block diagram of a system that facilitates intra-eNode B handover, in which a HO Command message transfer is depicted. The system300A includes user equipment302that is communicatively coupled to a base station304(referred to as source eNode B) in a wireless manner. With reference toFIGS. 3 and 4, Uu (316416) is an external interface, connecting the eNode B with the UE, and X2(318418) is an interface between eNode Bs including both a control and a user plane. User equipment302can be mobile in nature, such that quality associated with signals received from base station304can vary as UE302translates within a sector or to a different sector within the same cell requiring an intra-eNode B handover. The common understanding is that an HO Command314is a RRC signaling message, where the message is physically transmitted by the source cell or eNode B304in a regular handover. In addition, HO Command protocol termination for particular physical network entities can be described as being created by the RRC310in the source eNB304, in case of intra-eNB handover.

FIG. 3Billustrates an exemplary non-limiting high-level block diagram of a system that facilitates inter-eNode B handover, to which various aspects of the present invention are applicable. The system300B includes user equipment302that is communicatively coupled to a base station304(referred to as source eNode B) in a wireless manner. User equipment302can be mobile in nature, such that quality associated with signals received from base station304can vary as UE302translates within a geographic region requiring inter-eNode B handover to a target eNode B306. As described above, for the case of inter-eNB handover, RRC is terminated in the eNB (304306) as opposed to the RNC in UMTS. Thus, it is possible that the target eNB306supports a newer RRC protocol version with respect to the one that the source eNB304implements. As a result, without modifications to the UMTS inter-Node B handover procedure, target eNB306can be prevented from configuring radio parameters that are only realized by the target eNB RRC protocol312, because such a configuration may not be understood by the source eNB304.

The following discussion provides additional background information regarding signaling between the network (e.g., base station304and or system controller230) and the wireless terminal (e.g., UE302or access terminal220) in the context of UMTS. In an aspect, logical channels are classified into Control Channels and Traffic Channels. Logical Control Channels comprise Broadcast Control Channel (BCCH), which is a DL channel for broadcasting system control information, Paging Control Channel (PCCH), which is a DL channel that transfers paging information, and Multicast Control Channel (MCCH), which is point-to-multipoint DL channel used for transmitting Multimedia Broadcast and Multicast Service (MBMS) scheduling and control information for one or several Multicast Traffic Channels (MTCHs). Generally, after establishing Radio Resource Control (RRC) connection, this channel is only used by UEs302that receive MBMS. Dedicated Control Channel (DCCH) is a point-to-point bi-directional channel that transmits dedicated control information and used by UEs302having an RRC connection. In a further aspect, logical traffic channels comprise a Dedicated Traffic Channel (DTCH), which is point-to-point bi-directional channel, dedicated to one UE for the transfer of user information, and also a MTCH for Point-to-multipoint DL channel for transmitting traffic data.

In a further aspect, transport channels are classified into DL and UL. DL transport channels comprise a Broadcast Channel (BCH), Downlink Shared Data Channel (DL-SDCH), and a Paging Channel (PCH), wherein the PCH for support of UE power saving (Discontinuous Reception (DRX) cycle is indicated by the network to the UE), broadcasted over an entire cell and mapped to PHY resources, which can be used for other control/traffic channels. The UL transport channels comprise a Random Access Channel (RACH), a Request Channel (REQCH), a Uplink Shared Data Channel (UL-SDCH) and plurality of PHY channels. The PHY channels comprise a set of DL channels and UL channels.

The DL PHY channels comprise:

Common Pilot Channel (CPICH)

Common Control Channel (CCCH)

Shared DL Control Channel (SDCCH)

Multicast Control Channel (MCCH)

Shared UL Assignment Channel (SUACH)

DL Physical Shared Data Channel (DL-PSDCH)

UL Power Control Channel (UPCCH)

Paging Indicator Channel (PICH)

Load Indicator Channel (LICH)

The UL PHY Channels comprises:

Physical Random Access Channel (PRACH)

Channel Quality Indicator Channel (CQICH)

Antenna Subset Indicator Channel (ASICH)

Shared Request Channel (SREQCH)

UL Physical Shared Data Channel (UL-PSDCH)

Broadband Pilot Channel (BPICH)

In accordance with various non-limiting embodiments, the invention provides architectural and protocol changes for inter-node handover procedure. According to various aspects of the invention, logical protocol termination can be implemented between the UE302and the target eNB306for inter-eNB HO signaling. Advantageously, protocol termination between UE and the target eNB enables elimination of the UMTS HO Complete message for LTE, which allows for relatively more simple protocol implementations. According to further aspects of the invention, a Measurement Report message and a HO Command314message can be forwarded to the target BS306and the UE302respectively by the source BS304.

In further non-limiting embodiments, the HO Command message314can be encapsulated into an appropriate RRC message (e.g., a RRC direct transfer) by the source eNB304. Advantageously, the source eNB304does not require the ability to understand all the contents in the HO Command message314. Thus, source eNB304can minimally require only the ability to identify the HO Command message314as a HO Command message, according to various embodiments. In further embodiments, the source eNB404can include the ability to discern the HO Command message destination. Advantageously, the forwarding mechanism of the present invention does not require the relatively more complicated coordination mechanism between the source BS and the target BS of UMTS, which may be challenging in the multi-vendor network. As will be appreciated, the disclosed changes enable improved interoperability between eNBs implementing different protocol version or between eNBs from different vendors, which in turn enables frequent protocol upgrades. Additionally, according to further non-limiting embodiments, the invention enables the target BS to configure a new radio configuration that is unsupported by the source BS.

For the purposes of description of particular non-limiting embodiments of the invention, the following additional UMTS nomenclature is used: Radio Link Control (RLC) is a sub-layer of the radio interface that provides reliability; Transparent Mode (RLC-TM) is the transparent service in RLC, which functions include but are not limited to transfer of user data and segmentation and reassembly; Packet Data Convergence Protocol (PDCP) is used in UMTS to format the data into a suitable structure prior to transfer over the air interface; Serving Radio Network Subsystem (SRNS) refers to the fact that there is one SRNS for each UE that has a connection to the UTRAN, and which controls the RRC connection between a UE and the UTRAN; and COUNT-C is a ciphering sequence number in the UMTS encryption algorithm, which is updated sequentially for each plaintext block. While various embodiments are described with respect to UMTS, UTRAN, or E-UTRAN, one having ordinary skill in the art would recognize that various modifications could be made without departing from the spirit of the disclosed invention. Thus, it should be understood that the description herein is but one of many embodiments that may be possible while keeping within the scope of the claims appended hereto.

FIG. 4Aillustrates an exemplary non-limiting high-level block diagram of a system that facilitates inter-eNode B handover, according to various aspects of the invention. The system400A includes user equipment402that is communicatively coupled to a base station404(referred to as source eNode B) in a wireless manner. User equipment402can be mobile in nature, such that quality associated with signals received from base station404can vary as UE402translates within a geographic region requiring inter-eNode B handover to a target eNode B406. According to various nonlimiting embodiments of the invention, a HO Command message414can be created by the target eNB406and can be forwarded by the RRC in the source eNB404. According to further non-limiting embodiments, the HO Command message414can be encapsulated into an appropriate RRC message (e.g., a RRC direct transfer) by the source eNB404. Advantageously, the source eNB404does not require the ability to understand all the contents in the HO Command message414. Thus, source eNB404can minimally require only the ability to identify the HO Command message414as a HO Command message, according to various embodiments. In further embodiments, the source eNB404can include the ability to discern the HO Command message destination. Additionally, according to further non-limiting embodiments, the invention enables the target eNB406to configure a new radio configuration that is unsupported by the source eNB404.

FIG. 4Billustrates an exemplary non-limiting HO Command message structure for inter-eNode B handover, according to various aspects of the invention. As briefly described, the HO Command message (414) can be encapsulated into an appropriate RRC message400B (e.g., a RRC direct transfer) by the source eNB404and forwarded to the UE402. For example, the HO Command message426from the target eNB406can be encapsulated into the source eNB RRC message420, wherein the HO command message412remains self-decodable, according to various aspects of the invention. According to further aspects of the invention, integrity protection422and ciphering428can be performed by the source eNB404based on a pre-existing security relationship between the source eNB404and a mobile device associated with the HO command message. Advantageously, the method does not require a new security association between the UE and the target node. For example, an existing security association can be provided by any one or more of existing radio interface layers, sublayers, protocols, and/or the like, or any combination thereof (e.g., RLC, PDCP, etc.). As a further example, an RRC header424comprising information (e.g., message discriminator, transaction identifier, and the like) can be added by the source eNB404. According to various aspects of the present invention, the provided message structure400B advantageously enables usage of a new version radio configuration of the target eNode B406even if the source eNB404does not support the corresponding protocol version. As a result, mobile operators can benefit from frequent protocol upgrades, including physical layer upgrades.

FIG. 4Cillustrates an exemplary non-limiting signaling flow for inter-eNB handover, according to various aspects of the invention. As described, the HO Command message414can be encapsulated434into an appropriate RRC message400B (e.g., a RRC direct transfer) by the source eNB404and forwarded434to the UE402. In addition, according to further non-limiting embodiments of the invention, a Measurement Report message can be encapsulated432into an inter-node message (e.g., an inter-eNodeB message) and forwarded to the target eNB406by the source eNB404, where brackets “[ ]” indicate the encapsulation of the respective messages (432434). Because E-UTRAN RRM is more distributed than that of UTRAN, the source eNB404may not have accurate knowledge of the RRM situation of the target eNB406. Thus, the disclosed mechanisms provide further optimized inter-eNB mobility by allowing target eNB406processing of Measurement Reports430from the UE402, rather than source eNB processing (e.g., where the source eNB404only looks at the best cell indicated by the UE402). Advantageously, given the complete contents of the Measurement Report at the target eNB406, the provided mechanisms enable the target eNB406to make the best handover decision based on the most accurate RRM information. As a result, the typical message exchange in an inter-eNB handover can be described as occurring between the UE402and the target eNB406from a logical view point. According to various non-limiting embodiments, the provided message forwarding mechanism advantageously eliminates the need for complicated coordination between the source eNB404and the target eNB406, as well as the resultant interoperability problems between vendors and protocol versions.

As a further advantage, protocol termination between UE402and the target eNB406can enable elimination of the UMTS HO Complete message for LTE, which allows for relatively more simple protocol implementations. Experience shows that relying on HO Complete messages sometimes leads to unstable protocol behaviors. Indeed, some procedures in UMTS rely on the L2-ACK for the complete message. According to further aspects of the invention, this may be avoided for LTE by placing additional or supplemental information (e.g., UTRAN XX_complete message information such as RRC transaction identifier, activation time for integrity protection in UL, ciphering activation time for Radio Bearer (RB) using RLC-TM, PDCP sequence number info to support lossless SRNS relocation, START values for COUNT-C initialization (SRNS relocation)) in a HO Command message or in a Measurement Report message as described below. As such, UE402completion of the physical part of the handover can be obtained by L1/L2 signaling (e.g., as part of random access in the target cell).

For purposes of illustration, various UTRAN XX_complete message information has been described for optional and additional or supplemental inclusion in a HO Command or Measurement Report message to facilitate, create, generate, execute, or otherwise a handover complete event, function, indication, indicator, or otherwise in the wireless communication system. However, it should be appreciated that such descriptions should not be construed as being necessary to or limiting the claims appended hereto. As a result, without deviating from the scope of the present invention, depending on particular implementation details or design considerations, such information may or may not be included in a HO Command or Measurement Report message depending at least on one or more on the following considerations. For example, RRC transaction identifier may be more useful when a response message from the UE is XX_Failure, so that the network knows in which configuration the UE has failed. For successful cases, this information is not as relevant, unless the network initiates convoluted reconfigurations. As a further example, activation time for integrity protection in UL and START values for COUNT-C initialization (SRNS relocation) may be determined by the network and included in the HO Command message. In any event, this may be desirable for the simplicity of the security procedure in LTE. In addition, ciphering activation time for Radio Bearer (RB) using RLC-TM is probably not relevant any more in LTE due to ciphering for RLC-TM relying on RLC sequence number not envisioned for LTE. Furthermore, PDCP sequence number info from the UE may not be required to support lossless SRNS relocation. As a result, the present invention advantageously enables elimination of the potentially redundant or unnecessary HO Complete message in LTE allowing from minimal protocol complexity.

Now referring toFIG. 5, a communications apparatus500for employment within a wireless communications environment is illustrated. The apparatus500can be a base station304or a portion thereof or user equipment302or a portion thereof (such as a secure digital (SD) card coupled to a processor). Apparatus500can include a memory502that retains various instructions with respect to signal processing, scheduling communications, requesting measurement gaps, and/or the like. For instance, if apparatus500is user equipment as described below in connection withFIGS. 11-12and15, memory502can include instructions for transmitting a measurement report message to a source node for source node encapsulation into an inter-node message (e.g., an inter-eNodeB message) and forwarding to a target node. Memory502can can further include instructions for receiving a source node encapsulated handover command message forwarded from the target node, in accordance with various aspects of the invention. Further, memory502can include instructions for processing supplemental information included in the encapsulated handover command message to facilitate generating a handover complete indication. To that end, memory502can include instructions for appending additional information to the measurement report message to facilitate generating the handover complete indication. The above example instructions and other suitable instructions can be retained within memory502, and a processor504can be utilized in connection with executing the instructions (depending upon, for instance, measurement report comparison, outcomes of handover decisions, receipt of a handover command, etc.).

Also, as stated above, apparatus500can be a base station and/or a portion thereof as described below in connection withFIGS. 9-10and14. Base stations typically perform the roll of a source node or a target node depending on the particular circumstances of the UE with respect to various node Bs. As a source node example, memory502can include instructions for receiving a handover command created by a target base station, and for encapsulating the handover command into a Radio Resource Control message, according to various aspects described herein. Memory502can additionally include instructions for enciphering an encapsulated handover command utilizing a pre-existing security relation between a mobile device associated with the handover command and the source node, and for appending one or more of integrity protection information and a Radio Resource Control header, in accordance with further aspects of the invention. In addition, memory502can further include instructions for facilitating transmitting an encapsulated handover command to the mobile device. As a target node example, memory502can include instructions for receiving and processing a measurement report message, according to various aspects described herein. Memory502can additionally include instructions for processing additional information included in the measurement report message for creating a handover complete indication, in accordance with further aspects of the invention. In addition, memory502can further include instructions for determining, by the target node, a handover decision concerning a wireless terminal associated with the measurement report message. Moreover, memory502can include instructions for transmitting a handover command message to the wireless terminal, by the target node, wherein the handover command message includes supplemental information to facilitate creating the handover complete indication. Processor504can be employed to execute instructions retained within memory502. While several examples have been provided, it is understood that instructions described in the form of methodologies (e.g.,FIGS. 6-7) can be included within memory502and executed by processor504.

Referring toFIGS. 6 and 7, particular high-level methodologies for inter-eNode B handover in accordance with various embodiments are illustrated. While, for purposes of simplicity of explanation, the methodologies are shown and described as a series of acts, it is to be understood and appreciated that the methodologies are not limited by the order of acts, as some acts can occur in different orders and/or concurrently with other acts from that shown and described herein. For example, those skilled in the art will understand and appreciate that a methodology could alternatively be represented as a series of interrelated states or events, such as in a state diagram. Moreover, not all illustrated acts may be utilized to implement a methodology in accordance with one or more embodiments.

FIG. 6illustrates exemplary non-limiting high-level methodologies for inter-eNode B handover in accordance with various embodiments described herein. As described above, base stations can typically perform the roll of a source node or a target node depending on the particular circumstances of the UE with respect to various node Bs. As a result, methodologies are described with regard to the inter-eNode B handover in the context of a source node and a target node. For example, one methodology600can comprise receiving in a source node a handover command message created by a target node at602. At604, the handover command message can be encapsulated into a Radio Resource Control message which can also include appending integrity check information or an RRC header by the source node at606. At608, the encapsulated handover command message can be enciphered based on a pre-existing security association between a UE associated with the handover command message and the source node. Then the encapsulated handover command message can be transmitted to a wireless terminal associated with the handover command message at610. A further methodology652can comprise a target node receiving and processing a measurement report at652. At654, the target node can additionally process supplemental information included in the measurement report to facilitate generating a handover complete indication in the wireless communication system. At656, the target node determines a handover decision concerning a mobile device associated with the measurement report and transmits a handover command to the mobile device at658. In addition, the target can include supplemental information to facilitate generating a handover complete indication at660.

FIG. 7illustrates a further particular high-level methodology for inter-eNode B handover in accordance with various embodiments described herein. With regard to user equipment, one methodology can comprise transmitting a measurement report to a source node for source node encapsulation into an inter-node message (e.g., an inter-eNodeB message) and forwarding to a target node at702. Additionally at704, the UE can append additional information to the measurement report to facilitate generating a handover complete indication. At706, a source node encapsulated handover command message forwarded from the target node can be received at the UE, which can process supplemental information included in the encapsulated handover command message to facilitate generating a handover complete indication at608.

FIG. 8depicts an example communication system800implemented in accordance with various aspects including multiple cells: cell I802, cell M804. Note that neighboring cells802and804overlap slightly, as indicated by cell boundary region868, thereby creating potential for signal interference between signals transmitted by base stations in neighboring cells. Each cell802and804of system800includes three sectors. Cells which have not be subdivided into multiple sectors (N=1), cells with two sectors (N=2) and cells with more than 3 sectors (N>3) are also possible in accordance with various aspects. Cell802includes a first sector, sector I810, a second sector, sector II812, and a third sector, sector III814. Each sector810,812,814has two sector boundary regions; each boundary region is shared between two adjacent sectors.

Sector boundary regions provide potential for signal interference between signals transmitted by base stations in neighboring sectors. Line816represents a sector boundary region between sector I810and sector II812; line818represents a sector boundary region between sector II812and sector III814; line820represents a sector boundary region between sector III814and sector1810. Similarly, cell M804includes a first sector, sector I822, a second sector, sector II824, and a third sector, sector III826. Line828represents a sector boundary region between sector I822and sector II824; line830represents a sector boundary region between sector II824and sector III826; line832represents a boundary region between sector III826and sector I822. Cell I802includes a base station (BS), base station I806, and a plurality of end nodes (ENs) (e.g., wireless terminals) in each sector810,812,814. Sector I810includes EN(1)836and EN(X)838coupled to BS806via wireless links840,842, respectively; sector II812includes EN(1′)844and EN(X′)846coupled to BS806via wireless links848,850, respectively; sector III814includes EN(1″)852and EN(X″)854coupled to BS806via wireless links856,858, respectively. Similarly, cell M804includes base station M808, and a plurality of end nodes (ENs) in each sector822,824,826. Sector I822includes EN(1)836′ and EN(X)838′ coupled to BS M808via wireless links840′,842′, respectively; sector II824includes EN(1′)844′ and EN(X′)846′ coupled to BS M808via wireless links848′,850′, respectively; sector3826includes EN(1″)852′ and EN(X″)854′ coupled to BS808via wireless links856′,858′, respectively.

System800also includes a network node860which is coupled to BS I806and BS M808via network links862,864, respectively. Network node860is also coupled to other network nodes, e.g., other base stations, AAA server nodes, intermediate nodes, routers, etc. and the Internet via network link866. Network links862,864,866can be, e.g., fiber optic cables. Each end node, e.g., EN(1)836can be a wireless terminal including a transmitter as well as a receiver. The wireless terminals, e.g., EN(1)836can move through system800and can communicate via wireless links with the base station in the cell in which the EN is currently located. The wireless terminals, (WTs), e.g., EN(1)836, can communicate with peer nodes, e.g., other WTs in system800or outside system800via a base station, e.g., BS806, and/or network node860. WTs, e.g., EN(1)836can be mobile communications devices such as cell phones, personal data assistants with wireless modems, etc. Respective base stations or portions thereof can perform the various source and target node methodologies described herein with respect to inter-e Node B handover and generating a handover complete indication. The wireless terminals or portions thereof can use the provided mechanisms to facilitate inter-e Node B handover and generating a handover complete indication according to the various aspects provided herein.

FIG. 9illustrates a system that can be utilized in connection with inter-eNB handover mechanisms. System900comprises a base station902with a receiver910that receives signal(s) from one or more user devices904by way of one or more receive antennas906, and transmits to the one or more user devices904through a plurality of transmit antennas908. In one example, receive antennas906and transmit antennas908can be implemented using a single set of antennas. Receiver910can receive information from receive antennas906and is operatively associated with a demodulator912that demodulates received information. Receiver910can be, for example, a Rake receiver (e.g., a technique that individually processes multi-path signal components using a plurality of baseband correlators, . . . ), an MMSE-based receiver, or some other suitable receiver for separating out user devices assigned thereto, as will be appreciated by one skilled in the art. For instance, multiple receivers can be employed (e.g., one per receive antenna), and such receivers can communicate with each other to provide improved estimates of user data. Demodulated symbols are analyzed by a processor914similar to processor1106described below with regard toFIG. 11, and is coupled to a memory916that stores information related to user device assignments, lookup tables related thereto and the like. Receiver output for each antenna can be jointly processed by receiver910and/or processor914. A modulator918can multiplex the signal for transmission by a transmitter920through transmit antennas908to user devices904.

FIG. 10illustrates an example base station1000in accordance with various aspects of the present invention. Base station1000or portions thereof implements various aspect of the present invention. For example, base station1000can perform forwarding and encapsulation as well as issue handover commands, according to various aspects of the invention. Base station1000can be used as any one of base stations806,808of the system800ofFIG. 8. The base station1000includes a receiver1002, a transmitter1004, a processor1006, e.g., CPU, an input/output interface1008and memory1010coupled together by a bus1009over which various elements1002,1004,1006,1008, and1010can interchange data and information.

Sectorized antenna1003coupled to receiver1002is used for receiving data and other signals, e.g., channel reports, from wireless terminals transmissions from each sector within the base station's cell and can comprise one or more receive antennas. Sectorized antenna1005coupled to transmitter1004is used for transmitting data and other signals, e.g., control signals, pilot signal, beacon signals, etc. to wireless terminals1200(seeFIG. 12) within each sector of the base station's cell. In various aspects, base station1000can employ multiple receivers1002and multiple transmitters1004, e.g., an individual receiver1002for each sector and an individual transmitter1004for each sector. Processor1006, can be, e.g., a general purpose central processing unit (CPU). Processor1006controls operation of base station1000under direction of one or more routines1018stored in memory1010and implements the methods. I/O interface1008provides a connection to other network nodes, coupling the BS1000to other base stations, access routers, AAA server nodes, etc., other networks, and the Internet. Memory1010includes routines1018and data/information1020.

Data/information1020includes data1036, tone subset allocation sequence information1038including downlink strip-symbol time information1040and downlink tone information1042, and wireless terminal (WT) data/info1044including a plurality of sets of WT information: WT1info1046and WT N info1060. Each set of WT info, e.g., WT1info1046includes data1048, terminal ID1050, sector ID1052, uplink channel information1054, downlink channel information1056, and mode information1058.

Routines1018include communications routines1022and base station control routines1024. Base station control routines1024includes a scheduler module1026and signaling routines1028including a tone subset allocation routine1030for strip-symbol periods, other downlink tone allocation hopping routine1032for the rest of symbol periods, e.g., non strip-symbol periods, and a beacon routine1034.

Data1036includes data to be transmitted that will be sent to encoder1014of transmitter1004for encoding prior to transmission to WTs, and received data from WTs that has been processed through decoder1012of receiver1002following reception. Downlink strip-symbol time information1040includes the frame synchronization structure information, such as the superslot, beaconslot, and ultraslot structure information and information specifying whether a given symbol period is a strip-symbol period, and if so, the index of the strip-symbol period and whether the strip-symbol is a resetting point to truncate the tone subset allocation sequence used by the base station. Downlink tone information1042includes information including a carrier frequency assigned to the base station1000, the number and frequency of tones, and the set of tone subsets to be allocated to the strip-symbol periods, and other cell and sector specific values such as slope, slope index and sector type.

Data1048can include data that WT11200has received from a peer node, data that WT11200desires to be transmitted to a peer node, and downlink channel quality report feedback information. Terminal ID1050is a base station1000assigned ID that identifies WT11200. Sector ID1052includes information identifying the sector in which WT11200is operating. Sector ID1052can be used, for example, to determine the sector type. Uplink channel information1054includes information identifying channel segments that have been allocated by scheduler1026for WT11200to use, e.g., uplink traffic channel segments for data, dedicated uplink control channels for requests, power control, timing control, number of active streams etc. Each uplink channel assigned to WT11200includes one or more logical tones, each logical tone following an uplink hopping sequence according to various aspects of the present invention. Downlink channel information1056includes information identifying channel segments that have been allocated by scheduler1026to carry data and/or information to WT11200, e.g., downlink traffic channel segments for user data. Each downlink channel assigned to WT11200includes one or more logical tones, each following a downlink hopping sequence. Mode information1058includes information identifying the state of operation of WT11200, e.g. sleep, hold, on.

Communications routines1022control the base station1000to perform various communications operations and implement various communications protocols. Base station control routines1024are used to control the base station1000to perform basic base station functional tasks, e.g., signal generation and reception, scheduling, and to implement the steps of the method of some aspects including transmitting signals to wireless terminals using the tone subset allocation sequences during the strip-symbol periods.

Signaling routine1028controls the operation of receiver1002with its decoder1012and transmitter1004with its encoder1014. The signaling routine1028is responsible for controlling the generation of transmitted data1036and control information. Tone subset allocation routine1030constructs the tone subset to be used in a strip-symbol period using the method of the aspect and using data/information1020including downlink strip-symbol time info1040and sector ID1052. The downlink tone subset allocation sequences will be different for each sector type in a cell and different for adjacent cells. The WTs1200receive the signals in the strip-symbol periods in accordance with the downlink tone subset allocation sequences; the base station1000uses the same downlink tone subset allocation sequences in order to generate the transmitted signals. Other downlink tone allocation hopping routine1032constructs downlink tone hopping sequences, using information including downlink tone information1042, and downlink channel information1056, for the symbol periods other than the strip-symbol periods. The downlink data tone hopping sequences are synchronized across the sectors of a cell. Beacon routine1034controls the transmission of a beacon signal, e.g., a signal of relatively high power signal concentrated on one or a few tones, which can be used for synchronization purposes, e.g., to synchronize the frame timing structure of the downlink signal and therefore the tone subset allocation sequence with respect to an ultra-slot boundary.

FIG. 11illustrates a system1100that can be utilized in connection with inter-eNode B handover mechanisms as described herein. System1100comprises a receiver1102that receives a signal from, for instance, one or more receive antennas, and performs typical actions thereon (e.g., filters, amplifies, downconverts, . . . ) the received signal and digitizes the conditioned signal to obtain samples. A demodulator1104can demodulate and provide received pilot symbols to a processor1106for channel estimation.

Processor1106can be a processor dedicated to analyzing information received by receiver component1102and/or generating information for transmission by a transmitter1114. Processor1106can be a processor that controls one or more portions of system1100, and/or a processor that analyzes information received by receiver1102, generates information for transmission by a transmitter1114, and controls one or more portions of system1100. System1100can include an optimization component1108that can optimize performance of user equipment before, during, and/or after performance of measurements with respect to one or more technologies and/or frequencies. Optimization component1108can be incorporated into the processor1106. It is to be appreciated that optimization component1108can include optimization code that performs utility based analysis in connection with requesting measurement gaps. The optimization code can utilize artificial intelligence based methods in connection with performing inference and/or probabilistic determinations and/or statistical-based determination in connection with encoding and decoding schemes.

System (user equipment)1100can additionally comprise memory1110that is operatively coupled to processor1106and that stores information such as measurement gap information, scheduling information, and the like, wherein such information can be employed in connection with allocating requesting measurement gaps and performing measurements during a measurement gap. Memory1110can additionally store protocols associated with generating lookup tables, etc., such that system1100can employ stored protocols and/or algorithms to increase system capacity. It will be appreciated that the data store (e.g., memories) components described herein can be either volatile memory or nonvolatile memory, or can include both volatile and nonvolatile memory. By way of illustration and not limitation, nonvolatile memory can include read only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM), which acts as external cache memory. By way of illustration and not limitation, RAM is available in many forms such as synchronous RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), and direct Rambus RAM (DRRAM). The memory1110is intended to comprise, without being limited to, these and any other suitable types of memory. Processor1106is connected to a symbol modulator1112and transmitter1114that transmits the modulated signal.

FIG. 12illustrates an exemplary wireless terminal (e.g., end node, mobile device, . . . )1200which can be used as any one of the wireless terminals (e.g., EN(1)836, of the system800shown inFIG. 8). Wireless terminal1200includes a receiver1202including a decoder1212, a transmitter1204including an encoder1214, a processor1206, and memory1208which are coupled together by a bus1210over which the various elements1202,1204,1206,1208can interchange data and information. Antenna1203used for receiving signals from a base station is coupled to receiver1202. Antenna1205used for transmitting signals, e.g., to a base station is coupled to transmitter1204. As described above, it is to be appreciated that various modifications are possible. The processor1206, e.g., a CPU controls the operation of the wireless terminal1200and implements methods by executing routines1220and using data/information1222in memory1208.

Data/information1222includes user data1234, user information1236, and tone subset allocation sequence information1250, in the example case of an OFDMA communication system. User data1234can include data, intended for a peer node, which can be routed to encoder1214for encoding prior to transmission by transmitter1204to base station1000, and data received from the base station1000which has been processed by the decoder1212in receiver1202. User information1236includes uplink channel information1238, downlink channel information1240, terminal ID information1242, base station ID information1244, sector ID information1246, and mode information1248. Uplink channel information1238includes information identifying uplink channels segments that have been assigned by base station1000for wireless terminal1200to use when transmitting to the base station1000. Uplink channels can include uplink traffic channels, dedicated uplink control channels, e.g., request channels, power control channels and timing control channels. In the example case of an OFDMA communication system, each uplink channel includes one or more logic tones, each logical tone following an uplink tone hopping sequence. In some embodiments, the uplink hopping sequences are different between each sector type of a cell and between adjacent cells.

Downlink channel information1240includes information identifying downlink channel segments that have been assigned by a base station to WT1200for use when the base station is transmitting data/information to WT1200. Downlink channels can include downlink traffic channels and assignment channels, each downlink channel including one or more logical tone, each logical tone following a downlink hopping sequence, which is synchronized between each sector of the cell.

User info1236also includes terminal ID information1242, which is a base station1000assigned identification, base station ID information1244which identifies the specific base station1000that WT has established communications with, and sector ID info1246which identifies the specific sector of the cell where WT1200is presently located. In an example OFDMA communication system, base station ID1244provides a cell slope value and sector ID info1246provides a sector index type; the cell slope value and sector index type can be used to derive tone hopping sequences. Mode information1248also included in user info1236identifies whether the WT1200is in sleep mode, hold mode, or on mode.

In some OFDMA embodiments, tone subset allocation sequence information1250includes downlink strip-symbol time information1252and downlink tone information1254. Downlink tone info1254includes information including a carrier frequency assigned to the base station1000, the number and frequency of tones, and the set of tone subsets to be allocated to the strip-symbol periods, and other cell and sector specific values such as slope, slope index and sector type.

Routines1220include communications routines1224and wireless terminal control routines1226. Communications routines1224control the various communications protocols used by WT1200. Wireless terminal control routines1226controls basic wireless terminal1200functionality including the control of the receiver1202and transmitter1204. Wireless terminal control routines1226include the signaling routine1228. In some OFDMA embodiments, tone subset allocation routine1230uses user data/info1222including downlink channel information1240, base station ID info1244, e.g., slope index and sector type, and downlink tone information1254in order to generate the downlink tone subset allocation sequences in accordance with some embodiments and process received data transmitted from base station1000.

FIG. 13illustrates an exemplary non-limiting block diagram of a communication system suitable for incorporating inter-eNode B handover mechanisms in accordance with various aspects of the invention, where a transmitter system1310(e.g., base station, access point, etc.) and a receiver system1350(access terminal, user equipment, mobile node, etc.) are in wireless communication in a MIMO system1300. At the transmitter system1310, traffic data for a number of data streams is provided from a data source1312to a transmit (TX) data processor1314. In an embodiment, each data stream is transmitted over a respective transmit antenna. TX data processor1314formats, codes, and interleaves the traffic data for each data stream based on a particular coding scheme selected for that data stream to provide coded data. In accordance with various embodiments of the invention, transmitter system1310facilitates inter-eNode B handover by forwarding to the receiver system1350the encapsulated handover commands.

The modulation symbols for all data streams are then provided to a TX MIMO processor1320, which may further process the modulation symbols (e.g., for OFDM). TX MIMO processor1320then provides NTmodulation symbol streams to NTtransmitters (TMTR)1322athrough1322t. In certain embodiments, TX MIMO processor1320applies beamforming weights to the symbols of the data streams and to the antenna from which the symbol is being transmitted.

Each transmitter1322receives and processes a respective symbol stream to provide one or more analog signals, and further conditions (e.g., amplifies, filters, and upconverts) the analog signals to provide a modulated signal suitable for transmission over the MIMO channel. NTmodulated signals from transmitters1322athrough1322tare then transmitted from NTantennas1324athrough1324t, respectively.

At receiver system1350, the transmitted modulated signals are received by NRantennas1352athrough1352rand the received signal from each antenna1352is provided to a respective receiver (RCVR)1354athrough1354r. Each receiver1354conditions (e.g., filters, amplifies, and downconverts) a respective received signal, digitizes the conditioned signal to provide samples, and further processes the samples to provide a corresponding “received” symbol stream.

An RX data processor1360then receives and processes the NRreceived symbol streams from NRreceivers1354based on a particular receiver processing technique to provide NT“detected” symbol streams. The RX data processor1360then demodulates, deinterleaves, and decodes each detected symbol stream to recover the traffic data for the data stream. The processing by RX data processor1360is complementary to that performed by TX MIMO processor1320and TX data processor1314at transmitter system1310.

A processor1370periodically determines which pre-coding matrix to use. Processor1370formulates a reverse link message comprising a matrix index portion and a rank value portion. The reverse link message may comprise various types of information regarding the communication link and/or the received data stream. The reverse link message is then processed by a TX data processor1338, which also receives traffic data for a number of data streams from a data source1336, modulated by a modulator1380, conditioned by transmitters1354athrough1354r, and transmitted back to transmitter system1310.

At transmitter system1310, the modulated signals from receiver system1350are received by antennas1324, conditioned by receivers1322, demodulated by a demodulator1340, and processed by a RX data processor1342to extract the reverse link message transmitted by the receiver system1350. Processor1330then determines which pre-coding matrix to use for determining the beamforming weights then processes the extracted message. According to various aspects of the invention, the transmitter system1310can, among other aspects of the invention, receive, encapsulate, and forward measurement reports from the receiver system1350.

With reference toFIG. 14, illustrated is an apparatus1400that facilitates inter-eNode B handover according to various non-limiting embodiments of the invention. For example, apparatus1400may reside at least partially within a base station. It is to be appreciated that apparatus1400is represented as including functional blocks, which may be functional blocks that represent functions implemented by a processor, software, or combination thereof (e.g., firmware). In addition, because base stations typically perform the roll of a source node or a target node depending on the particular circumstances of the UE with respect to various node Bs, functionality of a base station can include that functionality required for both target and source node operations. For example, apparatus1400includes a logical grouping1402of electrical components that can act in conjunction. For instance, source node logical grouping1402can include an electrical component1404for receiving a handover command created by a target node. Further, logical grouping1402can include an electrical component1406for encapsulating the handover command into a Radio Resource Control message as described in further detail supra in connection withFIGS. 4-6. Logical grouping1402can further include electrical components for enciphering an encapsulated handover command based on a pre-existing security association between a wireless terminal associated with the handover command and a source node1408, for appending one or more of integrity check information and a Radio Resource Control header1410, and for transmitting an encapsulated handover command to a wireless terminal associated with the handover command1412. As a further example, target node logical grouping1414can include an electrical component1416for receiving and processing measurement report information. Further, logical grouping1414can include an electrical component1418for processing supplemental information included in the measurement report information to facilitate executing a handover complete function. Logical grouping1414can further include electrical components for determining a handover decision concerning a wireless terminal associated with the measurement report information1420, for transmitting a handover command to the wireless terminal1422, and for including additional information in the handover command to facilitate executing a handover complete function1424. Additionally, apparatus1400can include a memory1426that retains instructions for executing functions associated with the electrical components of logical groupings1402and1414. While shown as being external to memory1426, it is to be understood that one or more of electrical components of logical groupings1402and1414may exist within memory1426.

With reference toFIG. 15, illustrated is an apparatus1500that enables inter-eNode B handover according to various non-limiting embodiments of the invention. Apparatus1500may reside at least partially within a wireless terminal, for instance. It is to be appreciated that apparatus1500is represented as including functional blocks, which may be functional blocks that represent functions implemented by a processor, software, or combination thereof (e.g., firmware). Apparatus1500includes a logical grouping1502of electrical components that can act in conjunction. For instance, logical grouping1502can include an electrical component for transmitting measurement report information to a source base station for source base station encapsulation into an inter-node message (e.g., an inter-eNodeB message) and forwarding to a target base station1504. Further, logical grouping1502can include an electrical component for receiving a source base station encapsulated handover command forwarded from the target base station1506as described in further detail supra in connection withFIGS. 4,5, and7. In addition, logical grouping1502can include an electrical component for processing supplemental information included in the encapsulated handover command to facilitate generating a handover complete indication1508. Further, logical grouping1502can include an electrical component for appending additional information to the measurement report information to facilitate generating the handover complete indication1510. Additionally, apparatus1500can include a memory1512that retains instructions for executing functions associated with electrical components1504,1506,1508and1510. While shown as being external to memory1512, it is to be understood that one or more of electrical components1504,1506,1508and1510may exist within memory1512.

Various embodiments of the present invention are directed to an apparatus, e.g., a mobile node such as a mobile terminal, a base station, or a communications system which implement some embodiments. In some embodiments the access nodes are implemented as base stations which establish communications links with mobile nodes using OFDM and/or CDMA. In various embodiments the mobile nodes are implemented as notebook computers, personal data assistants (PDAs), or other portable devices including receiver/transmitter circuits and logic and/or routines, for implementing the methods of some embodiments.

Further embodiments are also directed to methods, e.g., method of controlling and/or operating mobile nodes, base stations and/or communications systems, e.g., hosts, in accordance with some embodiments. In various embodiments, nodes described herein are implemented using one or more modules to perform the steps corresponding to one or more methods of some embodiments, for example, message generation and/or transmission, message reception and/or processing, message encapsulation, etc. Thus, in some embodiments various features of some embodiments are implemented using modules. Such modules can be implemented using software, hardware or a combination of software and hardware as described below.

It is understood that the specific order or hierarchy of steps in the processes disclosed is an example of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged while remaining within the scope of the present disclosure. The method claims appended herein present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

Still further embodiments are also directed to machine readable medium, e.g., ROM, RAM, CDs, hard discs, etc., which include machine readable instructions for controlling a machine, e.g., general purpose computer with or without additional hardware, to implement all or portions of the above described methods, e.g., in one or more nodes. Accordingly, among other things, some embodiments are directed to a machine-readable medium including machine executable instructions for causing a machine, e.g., processor and associated hardware, to perform one or more of the steps of the above-described method(s).

According to an example, one or more methods presented above can include making inferences pertaining to comparing measurement reports. In accordance with another example, an inference may be made related to making handover decisions. It will be appreciated that the foregoing examples are illustrative in nature and are not intended to limit the number of inferences that can be made or the manner in which such inferences are made in conjunction with the various embodiments and/or methods described herein.

Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, firmware, middleware, microcode, or any combination thereof. To clearly illustrate this interchangeability, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware, software, or otherwise depends upon the particular application and design constraints imposed on the overall system. Skilled artisans can implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

The various illustrative logical blocks, modules, and circuits described in connection with the embodiments disclosed herein can be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, discrete gate or transistor logic, discrete hardware components, or other electronic units, or any combination thereof designed to perform the functions described herein. Furthermore, a general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. Additionally, a processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

The steps of a method or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in software module (e.g., procedures, functions, and so on) executed by a processor, or in a combination of the two that perform the functions described herein. Software code can be stored in memory units and executed by processors. Software modules can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. A memory unit can be implemented within the processor or external to the processor, in which case it can be communicatively coupled to the processor through various means. For example, an exemplary storage medium can be coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium can be integral to the processor. The processor and the storage medium can reside in an ASIC, which in turn can reside in a user terminal. In the alternative, the processor and the storage medium can reside as discrete components in a user terminal.

What has been described above includes embodiments of the disclosed subject matter to enable any person skilled in the art to make or use the present disclosure. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing such subject matter. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. Accordingly, the subject matter is intended to embrace all such alterations, modifications, and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.