WO2014161170A1

WO2014161170A1 - Method and apparatus for time switched uplink in a dual connectivity environment

Info

Publication number: WO2014161170A1
Application number: PCT/CN2013/073696
Authority: WO
Inventors: Wei Bai; Na WEI; Jing HAN; Pengfei Sun; Xinying Gao; Lili Zhang; Haiming Wang
Original assignee: Broadcom Corporation
Priority date: 2013-04-03
Filing date: 2013-04-03
Publication date: 2014-10-09

Abstract

A method, apparatus and computer program product are provided in order to support time switched data transmissions in a dual connectivity environment. The method may include receiving a signal to configure a semi-static predefined pattern for uplink (UL) transmissions by the communication device, wherein the predefined pattern ensures that the communication device communicates exclusively with one of the plurality of links at a time, and causing the communication device to transmit data to the plurality of links according to the predefined pattern. The signal may comprise a radio resource control (RRC) signal. The method may further include receiving a first link activation message from a first link of the plurality of links, the first link activation message indicating that the communication device will exclusively transmit data to the first link. A corresponding apparatus and computer program product are also provided.

Description

METHOD AND APPARATUS FOR TIME SWITCHED UPLINK IN A DUAL CONNECTIVITY ENVIRONMENT

TECHNOLOGICAL FIELD

[0001] Embodiments of the present invention relate generally to communications technology and, more particularly, to a method and apparatus enabling time switched transmissions in a dual connectivity environment.

BACKGROUND

[0002] Dual connectivity, also known as inter-Evolved Node B (eNB) carrier aggregation (CA) or multi-stream connection, has recently gained significant interest in the 3^rd Generation Partnership Project (3GPP). The targeted scenario is to use a macro cell (operating at 2GHz) to provide and control the mobility of user equipment (UE), while using a local area (LA) cell (operating at 3.5GHz) to offload the traffic. One of the attractive properties of a LA cell operating at 3.5GHz is that it provides up to a 100MHz continuous frequency resource. Accordingly, one very likely operative sequence using dual connectivity may be to only use the eNB of the macro cell to transmit important C- plane signaling and provide mobility support, while using the LA cell to transmit almost all traffic to and from the UE. Besides the abundant frequency resource, there are also other benefits of routing UE traffic through the LA cell on 3.5GHz: such routing could reduce the power consumption of the UE because the UE will have better channel quality connecting to the LA cell with a small packet loss (PL); in addition, such routing could improve spectrum efficiency by increasing reuse factor.

[0003] Despite this benefit of routing most of the UE traffic through the LA cell, the macro cell link is still desired to compensate for the small coverage and higher risk of link failure of the LA cell. Thus, a dual connectivity cell scenario is considered to be an important feature for small cell enhancements. In this regard, one issue need to be considered for dual connectivity is whether the UE can support simultaneous transmission and reception on both links. Supporting this feature depends on several factors, such as power consumption, synchronization, RF architectures, etc. [0004] Regarding the synchronization, we don't have a clear conclusion yet in 3GPP. Regarding the power consumption, if the macro eNB and the LA eNB both have their own schedulers (e.g., media access control (MAC) layer), it might be difficult to coordinate allocation of the transmission power of a given UE. For instance, without tight co-ordination between the two schedulers, the maximum power of the UE could easily be exceeded if the UE's maximum power is not bigger than the sum of the maximum power from two links. Furthermore, different UEs may implement the radio frequency (RF) differently, and transmitting one signal at one time will be easier for every UE.

[0005] Having a MAC layer at both the macro eNB and LA eNB may also require physical uplink control channel (PUCCH) transmitted on both links, to let the schedulers have instant hybrid automatic repeat request (HARQ) feedback. If a UE with dual connectivity cannot support simultaneous transmission on the uplink direction, then PUCCH for two links could not be transmitted at the same time, and simultaneous reception for the downlink direction could be also difficult and complex.

[0006] Besides the difficulty and complexity caused by simultaneous transmission and reception, another point is that once the UE could connect to a small cell, it is quite beneficial to use the small cell to route almost all traffic, from both a power consumption point of view and a link quality point of view. In this regard, not supporting

simultaneous transmission and reception would not cause a big loss of throughput.

BRIEF SUMMARY

[0007] A method, apparatus and computer program product are provided according to one embodiment of the present invention in order to support time switched uplink transmissions in a dual connectivity environment.

[0008] In one embodiment, a method is provided for use in a communication device connected to a plurality of links. The method includes receiving a signal to configure a semi-static predefined pattern for uplink (UL) transmissions by the communication device, wherein the predefined pattern ensures that the communication device communicates exclusively with one of the plurality of links at a time, and causing the communication device to transmit data to the plurality of links according to the predefined pattern. The signal may comprise a radio resource control (RRC) signal and the predefined pattern may require that the communication device communicates exclusively with a single link.

[0009] In some embodiments, the method includes receiving a first link activation message from a first link of the plurality of links, the first link activation message indicating that the communication device will exclusively transmit data to the first link. In this case, the first link activation message may comprise a MAC signal, and more specifically, a random access channel (RACH) procedure, a scheduling request (SR), or a sounding reference signal (SRS). Moreover, receiving the first link activation message may include causing a transmission timer for the first link to start running, and the communication device may exclusively transmit data to the first link while the transmission timer for the first link is running. In addition, the transmission timer stops running a predetermined time period after it starts running unless other signaling is received to restart the transmission timer. In response to stoppage of the transmission timer, the method may include causing the communication device to transmit data to the plurality of links according to the predefined pattern. The method may also include receiving a signal to restart the transmission timer, wherein the signal to restart the transmission timer may be a link activation message. The signal to restart the transmission timer may also be a physical downlink control channel (PDCCH) signal.

[0010] The method may further include causing the communication device to transmit a second link activation message to a second link of the plurality of links, the second link activation message indicating that the communication device will exclusively transmit data to the second link. In this regard, receiving the second link activation message may include causing a transmission timer for the second link to start running.

[0011] In some embodiments, the method may include causing the communication device to transmit a link change request, and may subsequently include receiving a link activation message based on the link change request. The link change request may be triggered by a measurement report indicating an imminent handover (HO), a high priority signal which must be transmitted on another link, or failure linking to an active link according to the predefined pattern. In this regard, the high priority signal may comprise a common control channel (CCCH) signal. [0012] In some embodiments, each of the plurality of links controls at least one of a femto cell, a pico cell, a micro cell, or a macro cell, and the communication device may be a mobile phone.

[0013] In another embodiment, an apparatus is provided for use in a communication device connected to a plurality of links. The apparatus may include at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the communication device to receive a signal to configure a semi-static predefined pattern for UL transmissions by the communication device, wherein the predefined pattern ensures that the communication device communicates exclusively with one of the plurality of links at a time, and cause the communication device to transmit data to the plurality of links according to the predefined pattern.

[0014] In another embodiment, a computer readable medium is provided for use in a communication device connected to a plurality of links. The computer program product comprising at least one computer readable storage medium storing computer readable instructions that, when executed, cause the communication device to receive a signal to configure a semi-static predefined pattern for UL transmissions by the communication device, wherein the predefined pattern ensures that the communication device communicates exclusively with one of the plurality of links at a time, and cause the communication device to transmit data to the plurality of links according to the predefined pattern.

[0015] In another embodiment, an apparatus is provided for use in a communication device connected to a plurality of links. The apparatus may include means for receiving a signal to configure a semi-static predefined pattern for UL transmissions by the communication device, wherein the predefined pattern ensures that the communication device communicates exclusively with one of the plurality of links at a time, and means for causing the communication device to transmit data to the plurality of links according to the predefined pattern.

[0016] In another example embodiment, a method is provided for use in a first link of a plurality of links. The method includes causing the first link to transmit a signal to configure a semi-static predefined pattern for UL transmissions by the communication device, wherein the predefined pattern ensures that the communication device communicates exclusively with one of the plurality of links at a time, and receiving data from the communication device according to the predefined pattern. The signal may comprise a RRC signal and the predefined pattern may require that the communication device communicates exclusively with a single link.

[0017] In some embodiments, the method includes causing the first link to transmit a link activation message to the communication device, the link activation message indicating that the communication device will exclusively transmit data to the first link. In this case, the link activation message may comprise a MAC signal, and more specifically, a RACH procedure, a SR, or a SRS. Moreover, causing the first link to transmit the link activation message may include causing a transmission timer for the first link to start running, and the communication device may exclusively transmit data to the first link while the transmission timer for the first link is running. In addition, the transmission timer stops running a predetermined time period after it starts running unless other signaling is received to restart the transmission timer. In response to stoppage of the transmission timer for the first link, the method may include receiving data from the communication device according to the predefined pattern. The method may also include causing the first link to transmit a signal to restart the transmission timer, wherein the signal to restart the transmission timer may be a link activation message. The signal to restart the transmission timer may also be a PDCCH signal.

[0018] In some embodiments, the method may include receiving a link change request, and may subsequently include causing the first link to transmit a link activation message based on the link change request. The link change request may be triggered by a measurement report indicating an imminent HO, a high priority signal which must be transmitted on another link, or failure linking to an active link according to the predefined pattern. In this regard, the high priority signal may comprise a CCCH signal.

[0019] In some embodiments, each of the plurality of links controls at least one of a femto cell, a pico cell, a micro cell, or a macro cell, and the communication device may be a mobile phone.

[0020] In another embodiment, an apparatus is provided for use in a first link of a plurality of links. The apparatus includes at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the first link to transmit a signal to configure a semi-static predefined pattern for UL transmissions by the communication device, wherein the predefined pattern ensures that the communication device communicates exclusively with one of the plurality of links at a time, and receive data from the communication device according to the predefined pattern.

[0021] In another embodiment, a computer readable medium is provided for use in a first link of a plurality of links. The computer program product includes at least one computer readable storage medium storing computer readable instructions that, when executed, cause the first link to transmit a signal to configure a semi-static predefined pattern for UL transmissions by the communication device, wherein the predefined pattern ensures that the communication device communicates exclusively with one of the plurality of links at a time, and receive data from the communication device according to the predefined pattern.

[0022] In another example embodiment, an apparatus is provided for use in a first link of a plurality of links. The apparatus includes means for causing the first link to transmit a signal to configure a semi-static predefined pattern for UL transmissions by the communication device, wherein the predefined pattern ensures that the communication device communicates exclusively with one of the plurality of links at a time, and means for receiving data from the communication device according to the predefined pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Having thus described the example embodiments of the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

[0024] Figure 1 is a schematic representation of a system having a communication device that may perform time switched transmissions in a dual connectivity environment;

[0025] Figure 2 is a block diagram of an apparatus that may be embodied by a communication device, in accordance with some example embodiments of the present invention; [0026] Figure 3 is a flow chart illustrating operations performed by an example communication device for time switched activation of individual links in a dual connectivity environment, in accordance with some example embodiments of the present invention;

[0027] Figure 4 is a flow chart illustrating example operations for time switched transmissions performed by an example cell, in accordance with some example embodiments of the present invention;

[0028] Figure 5 is a flow chart illustrating additional operations performed by an example communication device for initially configuring a semi-static predefined pattern for time switched uplink transmission and for requesting link changes, in accordance with some example embodiments of the present invention; and

[0029] Figure 6 is a flow chart illustrating additional operations performed by an example link for initially configuring a semi-static predefined pattern for time switched uplink transmission and for requesting link changes, in accordance with some example embodiments of the present invention.

DETAILED DESCRIPTION

[0030] The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the inventions are shown. Indeed, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.

[0031] As used in this application, the term "circuitry" refers to all of the

following: (a)hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and (b) to combinations of circuits and

software (and/or firmware), such as (as applicable): (i) to a combination of

processor(s) or (ii) to portions of processor(s)/software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and (c) to circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not

physically present.

[0032] This definition of "circuitry" applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term "circuitry" would also cover an implementation of merely a processor (or multiple processors) or portion of a processor and its (or their) accompanying software and/or firmware. The term "circuitry" would also cover, for example and if applicable to the particular claim element, a baseband integrated circuit or application specific integrated circuit for a mobile phone or a similar integrated circuit in server, a cellular network device, or other network device.

[0033] Although the method, apparatus and computer program product may be implemented in a variety of different system architectures, one example of a system that may be specifically configured in order to implement an example embodiment of the present invention is shown in Figure 1.

[0034] Referring now to Figure 1 , a system is shown that supports communications between a plurality of communication devices 102 (one of which is illustrated by way of example) and a network 106, such as an 802.1 1 network, a Long Term Evolution (LTE) network, an LTE- Advanced (LTE- A) network, a Global Systems for Mobile

communications (GSM) network, a Code Division Multiple Access (CDMA) network, e.g., a Wideband CDMA (WCDMA) network, a CDMA2000 network or the like, a General Packet Radio Service (GPRS) network or other type of network, via an access point 104.

[0035] The network 106 may include a collection of various different nodes, devices or functions that may be in communication with each other via corresponding wired and/or wireless interfaces. For example, the network may include one or more cells, which may include LA cells (small cells) such as femto cells, pico cells, or micro cells, and may also include macro cells. Each cell may include an access point 104 and may serve a respective coverage area. The access point 104 could be, for example, part of one or more cellular or mobile networks or public land mobile networks (PLM s). In turn, other devices such as processing devices (e.g., personal computers, server computers or the like) may be coupled to the communication device 102 and/or other communication devices via the network.

[0036] A communication device, such as the communication device 102 (also known as user equipment (UE), a mobile terminal or the like), may be in communication with other communication devices or other devices via the access point 104 of a cell and, in turn, the network 106. In some cases, the communication device 102 may include an antenna for transmitting signals to and for receiving signals from an access point 104. The communication device 102 may in some instances have dual connectivity, meaning that it is simultaneously connected to multiple access points 104, as shown in the example of Figure 1. As is described herein the communication device 102 and/or the access point 104 may take the form of a transmitter and/or receiver.

[0037] In some example embodiments, the communication device 102 may be a mobile communication device such as, for example, a mobile telephone, portable digital assistant (PDA), pager, laptop computer, STA, or any of numerous other hand held or portable communication devices, computation devices, content generation devices, content consumption devices, or combinations thereof. However, as is described herein, the communication device 102 may also take the form of a communications enabled appliance, such as a thermostat configured to connect with an access point 104. Other such devices that are configured to connect to the network include, but are not limited to a refrigerator, a security system, a home lighting system, and/or the like. As such, the communication device 102 may include one or more processors that may define processing circuitry and a processing system, either alone or in combination with one or more memories. The processing circuitry may utilize instructions stored in the memory to cause the communication device 102 to operate in a particular way or execute specific functionality when the instructions are executed by the one or more processors. The communication device 102 may also include communication circuitry and corresponding hardware/software to enable communication with other devices and/or the network 106. Regardless of the type of communication device, the communication device may communicate with a given cell via an access point 104, such as a base station, a Node B, an evolved Node B (eNB), a relay node or an 802.1 1 or other type of access point. [0038] The communication device 102 and a network entity, such as an eNB, or link, that manages the access point 104 of a cell, may each embody or otherwise be associated with an apparatus 200 that is generally depicted in Fig. 2 and that may be configured to perform various operations in accordance with an example embodiment of the present invention as described below, such as in conjunction with Figs. 3 and 5 from the perspective of a communication device 102, and Figs. 4 and 6 from the perspective of a network entity. However, it should be noted that the components, devices or elements described below may not be mandatory and thus some may be omitted in certain embodiments. Additionally, some embodiments may include further or different components, devices or elements beyond those shown and described herein.

[0039] As shown in Fig. 2, the apparatus 200 may include or otherwise be in communication with a processing system including, for example, processing circuitry 202 that is configurable to perform actions in accordance with example embodiments described herein. The processing circuitry may be configured to perform data processing, application execution and/or other processing and management services according to an example embodiment of the present invention. In some embodiments, the apparatus or the processing circuitry may be embodied as a chip or chip set. In other words, the apparatus or the processing circuitry may comprise one or more physical packages (e.g., chips) including materials, components and/or wires on a structural assembly (e.g., a baseboard). The structural assembly may provide physical strength, conservation of size, and/or limitation of electrical interaction for component circuitry included thereon. The apparatus or the processing circuitry may therefore, in some cases, be configured to implement an embodiment of the present invention on a single chip or as a single "system on a chip." As such, in some cases, a chip or chipset may constitute means for performing one or more operations for providing the functionalities described herein.

[0040] In an example embodiment, the processing circuitry 202 may include a processor 204 and memory 206 that may be in communication with or otherwise control a communication interface 208 and, in some cases in which the apparatus is embodied by the communication device 102, a user interface 210. As such, the processing circuitry may be embodied as a circuit chip (e.g., an integrated circuit chip) configured (e.g., with hardware, software or a combination of hardware and software) to perform operations described herein. However, in some embodiments, the processing circuitry may be embodied as a portion of mobile terminal or the access point.

[0041] The user interface 210 (if implemented) may be in communication with the processing circuitry 202 to receive an indication of a user input at the user interface and/or to provide an audible, visual, mechanical or other output to the user. As such, the user interface may include, for example, a keyboard, a mouse, a joystick, a display, a touch screen, a microphone, a speaker, and/or other input/output mechanisms. The apparatus 200 need not always include a user interface. For example, in instances in which the apparatus is embodied as an access point 104 of a cell, the apparatus may not include a user interface. As such, the user interface is shown in dashed lines in Fig. 2.

[0042] The communication interface 208 may include one or more interface mechanisms for enabling communication with other devices and/or networks. In some cases, the communication interface may be any means such as a device or circuitry embodied in either hardware, or a combination of hardware and software that is configured to receive and/or transmit data from to a network 106 and/or any other device or module in communication with the processing circuitry 202, such as between the communication device 102 and the access point 104. In this regard, the communication interface may include, for example, an antenna (or multiple antennas) and support hardware and/or software for enabling communications with a wireless communication network and/or a communication modem or other hardware/software for supporting communication via cable, digital subscriber line (DSL), universal serial bus (USB), Ethernet or other methods.

[0043] In an example embodiment, the memory 206 may include one or more non- transitory memory devices such as, for example, volatile and/or non-volatile memory that may be either fixed or removable. The memory may be configured to store information, data, applications, instructions or the like for enabling the apparatus 200 to carry out various functions in accordance with example embodiments of the present invention. For example, the memory could be configured to buffer input data for processing by the processor 204. Additionally or alternatively, the memory could be configured to store instructions for execution by the processor. As yet another alternative, the memory may include one of a plurality of databases that may store a variety of files, contents or data sets. Among the contents of the memory, applications may be stored for execution by the processor in order to carry out the functionality associated with each respective application. In some cases, the memory may be in communication with the processor via a bus for passing information among components of the apparatus.

[0044] The processor 204 may be embodied in a number of different ways. For example, the processor may be embodied as various processing means such as one or more of a microprocessor or other processing element, a coprocessor, a controller or various other computing or processing devices including integrated circuits such as, for example, an ASIC (application specific integrated circuit), an FPGA (field programmable gate array), or the like. In an example embodiment, the processor may be configured to execute instructions stored in the memory 206 or otherwise accessible to the processor. As such, whether configured by hardware or by a combination of hardware and software, the processor may represent an entity (e.g., physically embodied in circuitry - in the form of processing circuitry) capable of performing operations according to embodiments of the present invention while configured accordingly. Thus, for example, when the processor is embodied as an ASIC, FPGA or the like, the processor may be specifically configured hardware for conducting the operations described herein. Alternatively, as another example, when the processor is embodied as an executor of software instructions, the instructions may specifically configure the processor to perform the operations described herein.

[0045] As previously described, even in a dual connectivity environment, in which a UE is connected to multiple cells at a given time, it is quite beneficial to use only one cell to route almost all traffic, from both a power consumption point of view and a link quality point of view. In this regard, not supporting simultaneous transmission and reception would not cause a big loss of throughput. Accordingly, embodiments of the present invention manage the above-described problems using time switched uplink transmissions in a dual connectivity environment. However, given that each cell to which a given UE is connected may employ a scheduler, some coordination between the eNB of the first cell and the eNB of the second cell is needed to a certain degree.

[0046] To accomplish this coordination, embodiments of the present invention may include predefining a pattern of activation of each link (to a cell), after which MAC layer control signaling can switch the pattern in two directions. For a pattern switched due to MAC control signaling, there will be a timer running at the same time and the UE will switch back when the timer stops running.

[0047] Referring now to Fig. 3 , operations for time switched activation of individual links in a dual connectivity environment are shown. The operations are performed by a method, apparatus and computer program product of an example embodiment and illustrated from the perspective of an apparatus 200 that may be embodied by or otherwise associated with a UE in a dual connectivity environment, such as

communication device 102. In operation 302, the apparatus 200 may include means, such as communication interface 208 or the like, for receiving a first link activation message from a first link. The link activation message may comprise a MAC signal. More specifically, it may comprise a random access channel (RACH) procedure, a scheduling request (SR), or a sounding reference signal (SRS). After transmitting the link activation message, the apparatus 200 may transmit data exclusively to the first link.

[0048] In operation 304, the apparatus 200 may include means, such as the processing circuitry 202, the processor 204, or the like, for starting a transmission timer. In this regard, the transmission timer may be started upon transmission of the link activation message and the exclusivity of transmission to the first link may occur only while the transmission timer is running. Moreover, the transmission timer may stop running a predetermined time period after it starts running unless other signaling is received to restart the transmission timer. In some embodiments, the timer can be started and/or restarted by using a link activation message or a physical downlink control channel (PDCCH).

[0049] In operation 306, the apparatus 200 may include means, such as

communication interface 208 or the like, for receiving a second link activation message from a second link. In this regard, the second link activation message may indicate that the communication device will exclusively transmit data to the second link. In some embodiments, operation 306 is triggered by expiration of the transmission timer, in which case the UE link activation message may confirm that the UE and the network entities retain an aligned understanding of the "active" and "inactive" links, to avoid the risk of packet loss. In other embodiments, the second link activation message may be received in response to a buffer status report (BSR) that carries a path switch request. In accordance with the transmission of operation 306, in operation 308 the apparatus 200 may include means, such as the processing circuitry 202, the processor 204, or the like, for restarting the transmission timer. Similarly to with the first link activation message, the transmission timer may be restarted upon transmission of the second link activation message.

[0050] Referring now to Fig. 4, operations for time switched activation of individual links in a dual connectivity environment are shown from the perspective of a network entity, such as a link having an access point 104, which may be one of a plurality of links having connectivity with a UE. In operation 402, the apparatus 200 embodied by the network entity may include means, such as communication interface 208, for transmitting a first link activation message to a communication device, as previously described in connection with operation 302.

[0051] In operation 404, the apparatus 200 may include means, such as

communication interface 208 or the like, for starting a transmission timer. As described previously in connection with operation 304, the transmission timer may be started upon transmission of the link activation message and the exclusivity of transmission to the first link may occur only while the transmission timer is running. Moreover, the transmission timer may stop running a predetermined time period after it starts running unless other signaling is received to restart the transmission timer. In some embodiments, the timer can be started and/or restarted by using a link activation message or a physical downlink control channel (PDCCH). As previously noted, some coordination between the links enables the UE to send a link activation message to one link that is propagated to other links in connectivity with the UE, so that the UE and the network entities have an aligned understanding of the "active" and "inactive" links, to avoid the risk of packet loss.

[0052] In operation 406, the apparatus 200 may include means, such as

communication interface 208 or the like, for receiving data from the communication device.

[0053] Turning now to Figure 5, operations for initially configuring a semi-static predefined pattern for time switched uplink transmission and for requesting link changes are shown. The operations performed by a method, apparatus and computer program product of an example embodiment are illustrated from the perspective of an apparatus 200 that may be embodied by or otherwise associated with a UE in a dual connectivity environment, such as communication device 102. In operation 502, the apparatus 200 may include means, such as communication interface 208 or the like, for receiving a signal to configure a semi-static predefined pattern for uplink transmission to a plurality of links. In this regard, the signal may comprise a radio resource control (RRC) signal from a network entity, such as a link having an access point 104. The predefined pattern may be developed by multiple network entities (such as eNBs of multiple links in coordination), which develop the UL transmission pattern according primarily to the predicted traffic pattern and radio resource availability. In some embodiments, the predefined pattern may require that the communication device communicates exclusively with only a single link (such as using the LA cell, with which communication is most efficient), in which case MAC control signaling may be used to control possible macro link activation periods, in the manner previously described.

[0054] In operation 504, the apparatus 200 may include means, such as

communication interface 208 or the like, for transmitting data to the plurality of links according to the predefined pattern. In this regard, the predefined pattern may ensure that the apparatus 200 communicates exclusively with one network entity at a time.

[0055] Optionally, in operation 506, the apparatus 200 may include means, such as communication interface 208 or the like, for transmitting a link change request to the active link. The link change message may indicate that the communication device wishes to transmit data in violation of the predefined pattern. Further, the link change message may comprise a MAC signal. More specifically, it may comprise a RACH procedure, a SR, or a SRS, and may in some embodiments be equivalent to the link activation message described previously in conjunction with Figures 3 and 4. In some embodiments, the link change message may be triggered by a measurement report indicating an imminent handover (HO), a high priority signal which must be transmitted on another link, or a failure linking to an active link according to the predefined pattern. In this regard, the high priority signal may comprise a common control channel (CCCH) signal.

[0056] Optionally, in operation 508, the apparatus 200 may include means, such as communications interface 208 or the like, for receiving a MAC control signal in response to the link change request. The MAC control signal may indicate that the active link to the UE has been switched and may be received from the active link or from a currently inactive link. In some instances, the signal may be received from both links to ensure that the control signaling activating is correctly received by the UE.

[0057] Turning now to Figure 6, operations for initially configuring a semi-static predefined pattern for time switched uplink transmission and for requesting link changes are shown. The operations are illustrated from the perspective of a network entity, such as a link having an access point 104, which may be one of a plurality of network entities having connectivity with a UE. In operation 602, the apparatus 200 may include means, such as communication interface 208 or the like, for transmitting a signal to semi- statically configure a predefined pattern for uplink transmission to a plurality of links. In this regard, the signal may comprise a radio resource control (RRC) signal from a network entity, such as a link having an access point 104. The predefined pattern may be developed by multiple network entities (such as eNBs of multiple links in coordination), which develop the UL transmission pattern according primarily to the predicted traffic pattern and radio resource availability. In some embodiments, the predefined pattern may require that the communication device communicates exclusively with only a single link such as the LA cell, with which communication is most efficient, in which case MAC control signaling may be used to control possible macro link activation periods, in the manner previously described.

[0058] In operation 604, the apparatus 200 may include means, such as

communication interface 208 or the like, for receiving data according to the predefined pattern. In this regard, the predefined pattern may ensure that the apparatus 200 communicates exclusively with one network entity at a time.

[0059] In operation 606, the apparatus 200 may include means, such as

communication interface 208 or the like, for receiving a link change message disrupting the predefined pattern for uplink transmissions. The link change message may indicate that the communication device will transmit data in violation of the predefined pattern. Further, the link change message may comprise a MAC signal. More specifically, it may comprise a RACH procedure, a SR, or a SRS, and may in some embodiments be equivalent to the link activation message described previously in conjunction with Figures 3 and 4. In some embodiments, the link change message may be triggered by a measurement report indicating an imminent HO, a high priority signal which must be transmitted on another link, or a failure connecting to a link according to the predefined pattern. In this regard, the high priority signal may comprise a CCCH signal. In some embodiments, the apparatus 200 may include means, such as communication interface 208 or the like, for sending a confirmation of the link change message.

[0060] Optionally, in operation 608, the apparatus 200 may include means, such as communication interface 208 or the like, for transmitting a MAC control signal in response to a link change request from the communication device. The MAC control signal may indicate that the active link to the UE has been switched. In this situation, the apparatus 200 may further include means, such as communication interface 208 or the like, for transmitting a reactivation request to the UE if the link has download (DL) data to transmit to the UE. This reactivation request may comprise a PUCCH request for HARQ feedback.

[0061] In an instance in which the apparatus 200 has an "active" link to the UE, this process ensures that the control signaling activating another link is correctly received by the UE. However, in an instance in which the control signaling will be switching the apparatus 200 from an "inactive" link to an "active" link to the UE, any UL transmission from the UE to the apparatus 200 on the "inactive" link could be seen as successfully switching.

[0062] The above-described embodiments provide a method and apparatus enabling time switched uplink transmissions in a dual connectivity environment. Of course, in some embodiments, the above-described operations may be used to enable time switched downlink transmissions in a dual connectivity environment as well. However, for both uplink and downlink communications, for a UE in a dual connectivity environment, the network entities could efficiently control the UL switch using the time domain.

Moreover, the above-described embodiments ensure that the UE and the network entities have an aligned understanding about the "active" and "inactive" links at any given time, which avoids packet loss due to any misunderstanding. Furthermore, two eNBs could select or combine the proposed solution according to the backhaul link performance of the network. [0100] As noted above, Figs. 3-6 are flowcharts illustrating the operations performed by a method, apparatus and computer program product, such as apparatus 200 of Figure 2, from the perspective of the mobile terminal 102 and a network entity, such as the access point 104, respectively, in accordance with one embodiment of the present invention. It will be understood that each block of the flowcharts, and combinations of blocks in the flowcharts, may be implemented by various means, such as hardware, firmware, processor, circuitry and/or other device associated with execution of software including one or more computer program instructions. For example, one or more of the procedures described above may be embodied by computer program instructions. In this regard, the computer program instructions which embody the procedures described above may be stored by a memory 206 of an apparatus employing an embodiment of the present invention and executed by a processor 204 of the apparatus. As will be appreciated, any such computer program instructions may be loaded onto a computer or other

programmable apparatus (e.g., hardware) to produce a machine, such that the resulting computer or other programmable apparatus provides for implementation of the functions specified in the flowchart blocks. These computer program instructions may also be stored in a non-transitory computer-readable storage memory that may direct a computer or other programmable apparatus to function in a particular manner, such that the instructions stored in the computer-readable storage memory produce an article of manufacture, the execution of which implements the function specified in the flowchart blocks. The computer program instructions may also be loaded onto a computer or other programmable apparatus to cause a series of operations to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide operations for implementing the functions specified in the flowchart blocks. As such, the operations of Figs. 3-6, when executed, convert a computer or processing circuitry into a particular machine configured to perform an example embodiment of the present invention. Accordingly, the operations of Figs. 3-6 define algorithms for configuring a computer or processing circuitry 202, e.g., processor, to perform example embodiments. In some cases, a general purpose computer may be provided with an instance of the processor which performs the algorithms of Figs. 3-6 to transform the general purpose computer into a particular machine configured to perform the example embodiments.

[0101] Accordingly, blocks of the flowcharts support combinations of means for performing the specified functions and combinations of operations for performing the specified functions. It will also be understood that one or more blocks of the flowcharts, and combinations of blocks in the flowcharts, can be implemented by special purpose hardware-based computer systems which perform the specified functions, or

combinations of special purpose hardware and computer instructions.

[0102] In some embodiments, certain ones of the operations above may be modified or further amplified as described below. Moreover, in some embodiments, additional optional operations may optionally be included as shown, for example by the dashed lines in Figs. 2, 5, and 6. It should be appreciated that each of the modifications, optional additions or amplifications below may be included with the operations above either alone or in combination with any others among the features described herein.

[0103] Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although the foregoing descriptions and the associated drawings describe example embodiments in the context of certain example combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, different combinations of elements and/or functions than those explicitly described above are also contemplated as may be set forth in some of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

WHAT IS CLAIMED IS:

1. A method for use in a communication device connected to a plurality of links, the method comprising:

receiving a signal to configure a semi-static predefined pattern for uplink

(UL) transmissions by the communication device, wherein the predefined pattern ensures that the communication device communicates exclusively with one of the plurality of links at a time; and

causing the communication device to transmit data to the plurality of links according to the predefined pattern.

2. The method according to Claim 1, wherein the signal comprises a radio resource control (RRC) signal.

3. The method according to Claims 1 or 2, wherein the predefined pattern requires that the communication device communicates exclusively with a single link.

4. The method according to any of Claims 1 to 3, further comprising:

receiving a first link activation message from a first link of the plurality of links, the first link activation message indicating that the communication device will exclusively transmit data to the first link.

5. The method according to Claim 4, wherein the first link activation message comprises a MAC signal.

6. The method according to Claim 5, wherein the MAC signal comprises a random access channel (RACH) procedure, a scheduling request (SR), or a sounding reference signal (SRS).

7. The method according to any of Claims 4 to 6, wherein receiving the first link activation message includes causing a transmission timer for the first link to start running.

8. The method according to Claim 7, wherein the communication device exclusively transmits data to the first link while the transmission timer for the first link is running.

9. The method according to Claims 7 or 8, wherein the transmission timer stops running a predetermined time period after it starts running unless other signaling received to restart the transmission timer.

10. The method according to claim 9, further comprising, in response to stoppage of the transmission timer, causing the communication device to transmit data to the plurality of links according to the predefined pattern.

11. The method according to any of Claims 7 to 9, further comprising receiving a signal to restart the transmission timer.

12. The method according to Claim 1 1, wherein the signal to restart the transmission timer comprises a link activation message.

13. The method according to Claim 1 1 , wherein the signal to restart the transmission timer comprises a physical downlink control channel (PDCCH) signal.

14. The method according to any of Claims 4 to 13, further comprising:

causing the communication device to transmit a second link activation message to a second link of the plurality of links, the second link activation message indicating that the communication device will exclusively transmit data to the second link-:

15. The method according to Claim 14, wherein receiving the second link activation message includes causing a transmission timer for the second link to start running.

The method according to any of Claims 1 to 15, further comprising: causing the communication device to transmit a link change request.

17. The method according to Claim 16, further comprising:

receiving a link activation message based on the link change request.

18. The method according to Claim 16, wherein the link change request is triggered by:

a measurement report indicating an imminent handover (HO);

a high priority signal which must be transmitted on another link; or failure linking to an active link according to the predefined pattern.

19. The method according to Claim 18, wherein the high priority signal comprises a common control channel (CCCH) signal.

20. The method according to any of Claims 1 to 19, wherein each of the plurality of links controls at least one of a femto cell, a pico cell, a micro cell, or a macro cell.

21. The method according to any of Claims 1 to 20, wherein the

communication device comprises a mobile phone.

22. An apparatus for use in a communication device connected to a plurality of links, the apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the communication device to: receive a signal to configure a semi-static predefined pattern for uplink (UL) transmissions by the communication device, wherein the predefined pattern ensures that the communication device communicates exclusively with one of the plurality of links at a time; and

cause the communication device to transmit data to the plurality of links according to the predefined pattern.

23. The apparatus according to Claim 22, wherein the signal comprises a radio resource control (RRC) signal.

24. The apparatus according to Claims 22 or 23, wherein the predefined pattern requires that the communication device communicates exclusively with a single link.

25. The apparatus according to any of Claims 22 to 24, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the communication device to:

receive a first link activation message from a first link of the plurality of links, the first link activation message indicating that the communication device will exclusively transmit data to the first link.

26. The apparatus according to Claim 25, wherein the first link activation message comprises a MAC signal.

27. The apparatus according to Claim 26, wherein the MAC signal comprises a random access channel (RACH) procedure, a scheduling request (SR), or a sounding reference signal (SRS).

28. The apparatus according to any of Claims 25 to 27, wherein receiving the first link activation message includes causing a transmission timer for the first link to start running.

29. The apparatus according to Claim 28, wherein the communication device exclusively transmits data to the first link while the transmission timer for the first link is running.

30. The apparatus according to Claims 28 or 29, wherein the transmission timer stops running a predetermined time period after it starts running unless other signaling is received to restart the transmission timer.

31. The apparatus according to claim 30, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the communication device to, in response to stoppage of the transmission timer, transmit data to the plurality of links according to the predefined pattern.

32. The apparatus according to any of Claims 28 to 30, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the communication device to receive a signal to restart the transmission timer.

33. The apparatus according to Claim 32, wherein the signal to restart the transmission timer comprises a link activation message.

34. The apparatus according to Claim 32, wherein the signal to restart the transmission timer comprises a PDCCH signal.

35. The apparatus according to any of Claims 25 to 34, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the communication device to:

cause the communication device to transmit a second link activation message to a second link of the plurality of links, the second link activation message indicating that the communication device will exclusively transmit data to the second link.

36. The apparatus according to Claim 35, wherein receiving the second link activation message includes causing a transmission timer for the second link to start running.

37. The apparatus according to any of Claims 22 to 36, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the communication device to:

cause the communication device to transmit a link change request.

38. The apparatus according to Claim 37, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the communication device to:

receive a link activation message based on the link change request.

39. The apparatus according to Claim 37, wherein the link change request is triggered by:

a measurement report indicating an imminent HO;

40. The apparatus according to Claim 39, wherein the high priority signal comprises a CCCH signal.

41. The apparatus according to any of Claims 22 to 40, wherein each of the plurality of links controls at least one of a femto cell, a pico cell, a micro cell, or a macro cell.

42. The apparatus according to any of Claims 22 to 41, wherein the communication device comprises a mobile phone.

43. A computer program product for use in a communication device connected to a plurality of links, the computer program product comprising at least one computer readable storage medium storing computer readable instructions that, when executed, cause the communication device to:

receive a signal to configure a semi-static predefined pattern for UL transmissions by the communication device, wherein the predefined pattern ensures that the communication device communicates exclusively with one of the plurality of links at a time; and

44. The computer program product according to Claim 43, wherein the signal comprises a RRC signal.

45. The computer program product according to Claims 43 or 44, wherein the predefined pattern requires that the communication device communicates exclusively with a single link.

46. The computer program product according to any of Claims 43 to 45, wherein the computer readable instructions, when executed, further cause the communication device to:

47. The computer program product according to Claim 46, wherein the first link activation message comprises a MAC signal.

48. The computer program product according to Claim 47, wherein the MAC signal comprises a RACH procedure, a SR, or a SRS.

49. The computer program product according to any of Claims 46 to 48, wherein receiving the first link activation message includes causing a transmission timer for the first link to start running.

50. The computer program product according to Claim 49, wherein the communication device exclusively transmits data to the first link while the transmission timer for the first link is running.

51. The computer program product according to Claims 49 or 50, wherein the transmission timer stops running a predetermined time period after it starts running unless other signaling is received to restart the transmission timer.

52. The computer program product according to claim 51 , wherein the computer readable instructions, when executed, further cause the communication device to, in response to stoppage of the transmission timer, transmit data to the plurality of links according to the predefined pattern.

53. The computer program product according to any of Claims 49 to 51 , wherein the computer readable instructions, when executed, further cause the

communication device to receive a signal to restart the transmission timer.

54. The computer program product according to Claim 43, wherein the signal to restart the transmission timer comprises a link activation message.

55. The computer program product according to Claim 43, wherein the signal to restart the transmission timer comprises a PDCCH signal.

56. The computer program product according to any of Claims 46 to 55, wherein the computer readable instructions, when executed, further cause the

communication device to: cause the communication device to transmit a second link activation message to a second link of the plurality of links, the second link activation message indicating that the communication device will exclusively transmit data to the second link.

57. The computer program product according to Claim 56, wherein receiving the second link activation message includes causing a transmission timer for the second link to start running.

58. The computer program product according to any of Claims 43 to 57, wherein the computer readable instructions, when executed, further cause the

communication device to:

cause the communication device to transmit a link change request.

59. The computer program product according to Claim 58, wherein the computer readable instructions, when executed, further cause the communication device to:

receive a link activation message based on the link change request.

60. The computer program product according to Claim 58, wherein the link change request is triggered by:

a measurement report indicating an imminent HO;

61. The computer program product according to Claim 60, wherein the high priority signal comprises a CCCH signal.

62. The computer program product according to any of Claims 43 to 61 , wherein each of the plurality of links controls at least one of a femto cell, a pico cell, a micro cell, or a macro cell.

63. The computer program product according to any of Claims 43 to 62, wherein the communication device comprises a mobile phone.

64. An apparatus for use in a communication device connected to a plurality of links, the method comprising:

means for receiving a signal to configure a semi-static predefined pattern for UL transmissions by the communication device, wherein the predefined pattern ensures that the communication device communicates exclusively with one of the plurality of links at a time; and

means for transmitting data to the plurality of links according to the predefined pattern.

65. The apparatus according to Claim 64, wherein the signal comprises a RRC signal.

66. The apparatus according to Claims 64 or 65, wherein the predefined pattern requires that the communication device communicates exclusively with a single link.

67. The apparatus according to any of Claims 64 to 66, further comprising: means for receiving a first link activation message from a first link of the plurality of links, the first link activation message indicating that the communication device will exclusively transmit data to the first link.

68. The apparatus according to Claim 67, wherein the first link activation message comprises a MAC signal.

69. The apparatus according to Claim 68, wherein the MAC signal comprises a RACH procedure, a SR, or a SRS.

70. The apparatus according to any of Claims 67 to 69, wherein receiving the first link activation message includes causing a transmission timer for the first link to start running.

71. The apparatus according to Claim 70, wherein the communication device exclusively transmits data to the first link while the transmission timer for the first link is running.

72. The apparatus according to Claims 70 or 71 , wherein the transmission timer stops running a predetermined time period after it starts running unless other signaling is received to restart the transmission timer.

73. The apparatus according to claim 72, further comprising means for, in response to stoppage of the transmission timer, transmitting data to the plurality of links according to the predefined pattern.

74. The apparatus according to any of Claims 70 to 72, further comprising means for receiving a signal to restart the transmission timer.

75. The apparatus according to Claim 74, wherein the signal to restart the transmission timer comprises a link activation message.

76. The apparatus according to Claim 74, wherein the signal to restart the transmission timer comprises a PDCCH signal.

77. The apparatus according to any of Claims 67 to 76, further comprising: means for transmitting a second link activation message to a second link of the plurality of links, the second link activation message indicating that the communication device will exclusively transmit data to the second link.

78. The apparatus according to Claim 77, wherein receiving the second link activation message includes causing a transmission timer for the second link to start running.

The apparatus according to any of Claims 64 to 78, further comprising: means for transmitting a link change request.

The apparatus according to Claim 79, further comprising: means for receiving a link activation message based on the link change

81. The apparatus according to Claim 79, wherein the link change request is triggered by:

a measurement report indicating an imminent HO;

82. The apparatus according to Claim 81 , wherein the high priority signal comprises a CCCH signal.

83. The apparatus according to any of Claims 64 to 82, wherein each of the plurality of links controls at least one of a femto cell, a pico cell, a micro cell, or a macro cell.

84. The apparatus according to any of Claims 64 to 83, wherein the communication device comprises a mobile phone.

85. A method for use in a first link of a plurality of links, the method comprising:

causing the first link to transmit a signal to configure a semi-static predefined pattern for UL transmissions by the communication device, wherein the predefined pattern ensures that the communication device communicates exclusively with one of the plurality of links at a time; and

receiving data from the communication device according to the predefined pattern.

86. The method according to Claim 85, wherein the signal comprises a RRC signal.

87. The method according to Claims 85 or 86, wherein the predefined pattern requires that the communication device communicates exclusively with a single link.

88. The method according to any of Claims 85 to 87, further comprising: causing the first link to transmit a link activation message to the communication device, the link activation message indicating that the communication device will exclusively transmit data to the first link.

89. The method according to Claim 88, wherein the link activation message comprises a MAC signal.

90. The method according to Claim 89, wherein the MAC signal comprises a RACH procedure, a SR, or a SRS.

91. The method according to any of Claims 88 to 90, wherein causing the first link to transmit the link activation message includes causing a transmission timer for the first link to start running.

92. The method according to Claim 91, wherein the communication device exclusively transmits data to the first link while the transmission timer for the first link is running.

93. The method according to Claims 91 or 92, wherein the transmission timer for the first link stops running a predetermined time period after it starts running unless other signaling is transmitted to restart the transmission timer.

94. The method according to claim 93, further comprising, in response to stoppage of the transmission timer for the first link, receiving data from the

communication device according to the predefined pattern.

95. The method according to any of Claims 91 to 93, further comprising causing the first link to transmit a signal to restart the transmission timer.

96. The method according to Claim 95, wherein the signal to restart the transmission timer comprises a link activation message.

97. The method according to Claim 95, wherein the signal to restart the transmission timer comprises a PDCCH signal.

98. The method according to any of Claims 85 to 97, further comprising: receiving a link change request from the communication device.

99. The method according to Claim 98, further comprising:

causing the first link to transmit a link activation message based on the link change request.

100. The method according to Claim 98, wherein the link change request is triggered by:

a measurement report indicating an imminent HO;

101. The method according to Claim 100, wherein the high priority signal comprises a CCCH signal.

102. The method according to any of Claims 85 to 101 , wherein each of the plurality of links controls at least one of a femto cell, a pico cell, a micro cell, or a macro cell.

103. The method according to any of Claims 85 to 102, wherein the communication device comprises a mobile phone.

104. An apparatus for use in a first link of a plurality of links, the apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the first link to:

transmit a signal to configure a semi-static predefined pattern for UL transmissions by the communication device, wherein the predefined pattern ensures that the communication device communicates exclusively with one of the plurality of links at a time; and

receive data from the communication device according to the predefined pattern.

105. The apparatus according to Claim 104, wherein the signal comprises a RRC signal.

106. The apparatus according to Claims 104 or 105, wherein the predefined pattern requires that the communication device communicates exclusively with a single link.

107. The apparatus according to any of Claims 104 to 106, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the cause the first link to: transmit a link activation message to the communication device, the link activation message indicating that the communication device will exclusively transmit data to the first link.

108. The apparatus according to Claim 107, wherein the link activation message comprises a MAC signal.

109. The apparatus according to Claim 108, wherein the MAC signal comprises a RACH procedure, a SR, or a SRS.

110. The apparatus according to any of Claims 107 to 109, wherein

transmitting the link activation message includes causing a transmission timer for the first link to start running.

11 1. The apparatus according to Claim 110, wherein the communication device exclusively transmits data to the first link while the transmission timer for the first link is running.

112. The apparatus according to Claims 110 or 11 1, wherein the transmission timer for the first link stops running a predetermined time period after it starts running unless other signaling is transmitted to restart the transmission timer.

113. The apparatus according to claim 112, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the cause the first link to, in response to stoppage of the transmission timer for the first link, receive data from the communication device according to the predefined pattern.

114. The apparatus according to any of Claims 1 10 to 112, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the first link to transmit a signal to restart the transmission timer.

115. The apparatus according to Claim 1 14, wherein the signal to restart the transmission timer comprises a link activation message.

116. The apparatus according to Claim 1 14, wherein the signal to restart the transmission timer comprises a PDCCH signal.

117. The apparatus according to any of Claims 104 to 116, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the cause the first link to:

receive a link change request from the communication device.

118. The apparatus according to Claim 117, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the cause the first link to:

transmit a link activation message based on the link change request.

119. The apparatus according to Claim 1 17, wherein the link change request is triggered by:

a measurement report indicating an imminent HO;

120. The apparatus according to Claim 119, wherein the high priority signal comprises a CCCH signal.

121. The apparatus according to any of Claims 104 to 120, wherein each of the plurality of links controls at least one of a femto cell, a pico cell, a micro cell, or a macro cell.

122. The apparatus according to any of Claims 104 to 121 , wherein the communication device comprises a mobile phone.

123. A computer program product for use in a first link of a plurality of links, the computer program product comprising at least one computer readable storage medium storing computer readable instructions that, when executed, cause the first link to:

receive data from the communication device according to the predefined pattern.

124. The computer program product according to Claim 123, wherein the signal comprises a RRC signal.

125. The computer program product according to Claims 123 or 123, wherein the predefined pattern requires that the communication device communicates exclusively with a single link.

126. The computer program product according to any of Claims 123 to 125, wherein the computer readable instructions, when executed, further cause the first link to:

transmit a link activation message to the communication device, the link activation message indicating that the communication device will exclusively transmit data to the first link.

127. The computer program product according to Claim 126, wherein the link activation message comprises a MAC signal.

128. The computer program product according to Claim 127, wherein the MAC signal comprises a RACH procedure, a SR, or a SRS.

129. The computer program product according to any of Claims 126 to 128, wherein causing the first link to transmit the link activation message includes causing a transmission timer for the first link to start running.

130. The computer program product according to Claim 129, wherein the communication device exclusively transmits data to the first link while the transmission timer for the first link is running.

131. The computer program product according to Claims 129 or 130, wherein the transmission timer for the first link stops running a predetermined time period after it starts running unless other signaling is transmitted to restart the transmission timer.

132. The computer program product according to claim 131, wherein the computer readable instructions, when executed, further cause the first link to, in response to stoppage of the transmission timer for the first link, receive data from the

communication device according to the predefined pattern.

133. The computer program product according to any of Claims 129 to 131 , wherein the computer readable instructions, when executed, further cause the first link to transmit a signal to restart the transmission timer.

134. The computer program product according to Claim 133, wherein the signal to restart the transmission timer comprises a link activation message.

135. The computer program product according to Claim 133, wherein the signal to restart the transmission timer comprises a PDCCH signal.

136. The computer program product according to any of Claims 123 to 135, wherein the computer readable instructions, when executed, further cause the first link to:

receive a link change request from the communication device.

137. The computer program product according to Claim 136, wherein the computer readable instructions, when executed, further cause the first link to:

transmit a link activation message based on the link change request.

138. The computer program product according to Claim 136, wherein the link change request is triggered by:

a measurement report indicating an imminent HO;

139. The computer program product according to Claim 138, wherein the high priority signal comprises a CCCH signal.

140. The computer program product according to any of Claims 123 to 139, wherein each of the plurality of links controls at least one of a femto cell, a pico cell, a micro cell, or a macro cell.

141. The computer program product according to any of Claims 123 to 140, wherein the communication device comprises a mobile phone.

142. An apparatus for use in a first link of a plurality of links, the apparatus comprising:

means for transmitting a signal to configure a semi-static predefined pattern for UL transmissions by the communication device, wherein the predefined pattern ensures that the communication device communicates exclusively with one of the plurality of links at a time; and

means for receiving data from the communication device according to the predefined pattern.

143. The apparatus according to Claim 142, wherein the signal comprises a

RRC signal.

144. The apparatus according to Claims 142 or 143, wherein the predefined pattern requires that the communication device communicates exclusively with a single link.

145. The apparatus according to any of Claims 142 to 144, further comprising: means for transmitting a link activation message to the communication device, the link activation message indicating that the communication device will exclusively transmit data to the first link.

146. The apparatus according to Claim 145, wherein the link activation message comprises a MAC signal.

147. The apparatus according to Claim 146, wherein the MAC signal comprises a RACH procedure, a SR, or a SRS.

148. The apparatus according to any of Claims 145 to 147, wherein

149. The apparatus according to Claim 148, wherein the communication device exclusively transmits data to the first link while the transmission timer for the first link is running.

150. The apparatus according to Claims 148 or 149, wherein the transmission timer for the first link stops running a predetermined time period after it starts running unless other signaling is transmitted to restart the transmission timer.

151. The apparatus according to claim 150, further comprising means for, in response to stoppage of the transmission timer for the first link, receiving data from the communication device according to the predefined pattern.

152. The apparatus according to any of Claims 148 to 150, further comprising means for transmitting a signal to restart the transmission timer.

153. The apparatus according to Claim 152, wherein the signal to restart the transmission timer comprises a link activation message.

154. The apparatus according to Claim 152, wherein the signal to restart the transmission timer comprises a PDCCH signal.

155. The apparatus according to any of Claims 142 to 154, further comprising: means for receiving a link change request from the communication device.

156. The apparatus according to Claim 155, further comprising:

means for transmitting a link activation message based on the link change request.

157. The apparatus according to Claim 155, wherein the link change request is triggered by:

a measurement report indicating an imminent HO;

158. The apparatus according to Claim 157, wherein the high priority signal comprises a common control channel (CCCH) signal.

159. The apparatus according to any of Claims 142 to 158, wherein each of the plurality of links controls at least one of a femto cell, a pico cell, a micro cell, or a macro cell.

160. The apparatus according to any of Claims 142 to 159, wherein the communication device comprises a mobile phone.