WO2014110759A1

WO2014110759A1 - Flexible usage of special subframe for long term evolution time division duplex downlink-uplink

Info

Publication number: WO2014110759A1
Application number: PCT/CN2013/070605
Authority: WO
Inventors: Tao Chen; Chunyan Gao
Original assignee: Broadcom Corporation
Priority date: 2013-01-17
Filing date: 2013-01-17
Publication date: 2014-07-24

Abstract

A process, apparatus, and computer program product are described for providing flexible switching between legacy and new format downlink (DL) resource grants in a wireless communications network. The new format may be signaled by one bit or by two bits in the DL grant to indicate the length and format of physical downlink shared channel transmissions. During a flexible switching period from uplink (UL) to DL, a base station may signal both the legacy and new format resource grants to user equipment (UE). Once UE detects the two grants it may send an acknowledgement/negative acknowledgement (ACK/NACK) signal to activate the new DL grant using resources associated with the newly introduced grant. Alternatively, the base station may indicate a frequency shift Δf for ACK/NACK resources for UE to indicate readiness for new configuration.

Description

FLEXIBLE USAGE OF SPECIAL SUBFRAME FOR LONG TERM EVOLUTION TIME DIVISION DUPLEX DOWNLINK-UPLINK

TECHNOLOGICAL FIELD

The various embodiments described herein are related to the field of wireless mobile communications. They are particularly useful for next generation Long Term Evolution (LTE) network time division duplex (TDD) downlink-uplink (DL-UL) user equipment (UE) operation.

BACKGROUND

TDD offers flexible deployments without requiring a pair of spectrum resources. Currently, LTE TDD allows for asymmetric UL-DL allocations by providing seven different semi-statically configured uplink-downlink configurations. These allocations can provide between 40% and 90% DL subframes. The current mechanism for adapting UL-DL allocation is based on the system information change procedure. However, the semi-static allocation may not match the instantaneous traffic situation.

As presently specified, the existing LTE TDD system can support a slow UL-DL switching indicated by system information block 1 (SIBl) message. The flexible UL-DL switching feature has been identified to provide more system gain, which is required to be backward compatible with the legacy user equipment (UE).

Currently the legacy UEs can identify the UL-DL configuration based on the frame configuration information carried in SIBl message. The legacy UEs are not able to decode the new signaling that supports flexible UL-DL switching. The frame reconfiguration carried by the new signaling format is unknown to the legacy UEs. If the DL subframe in a frame configured via SIB 1 message is reconfigured as the UL subframe by the new signaling, the legacy UEs would be unaware of it and would likely perform radio resource management (RRM) measurement (e.g., reference signal received power (RSRP) and reference signal received quality (RSRQ)) and channel state information (CSI) measurement as before, supposing it to be still a DL subframe. This could lead to system crash due to some exceptional behaviors on RRM and packet scheduling.

Thus, it makes sense that the frame reconfiguration via the new signaling can be only allowed for "UL"->"DL".

However, referring to Table 1 , as currently specified for LTE, subframe #6 can be used for flexible switching in addition to subframes #3,#4,#7,#8 and #9.

. LTE TDD frame configu rations

The structure of the special subframe consists of three fields: Downlink Pilot Time Slot 11 (DwPTS), Guard Period 13 (GP) and Uplink Pilot Time Slot 15 (UpPTS), as presented in FIG. 1. DwPTS 11 are always reserved for downlink transmission. UpPTS 15 and the subframe immediately following the special subframe are always reserved for uplink transmission. GP 13 denotes the switching time between downlink and uplink. The configuration of the special subframe (SSF) is presented in Table 2. Table 2. DwPTS/GP/UpPTS length (OFDM symbols)

In the case of flexible switching, a SSF indicated by SIB1 would be reconfigured to a normal DL subframe (SF). A scheduling problem for resource utilization may arise for both legacy UEs and the next generation UEs. The legacy UEs may still take that subframe as a SSF whereas the next generation UE would identify it as a normal DL SF. In this case, the legacy UE can only receive DL transmission carried in the DwPTS field even though it is a normal DL SF. The remaining GP and UpPTS fields in this reconfigured DL subframe cannot be used by any UE according to the present specification, which would waste scarce resources.

For example, if the system is switching from frame configuration 0 (FC0 with a SSF in subframe #6) configured by SIB 1 to frame configuration 3 (FC3 with a normal DL SF in subframe #6) via the new signaling, then a legacy UE can only receive the data transmission carried on the DwPTS supposing it is a SSF. However, once a legacy UE is scheduled, the corresponding frequency resources in the remaining GP and UpPTS fields are difficult to utilize based on the present specification. BRIEF SUMMARY

A method is described comprising configuring a downlink subframe by selecting a downlink control information (DCI) format from one of: at least a first set of DCI bits to schedule a downlink transmission and a second set of DCI bits to schedule a downlink transmission; and configuring a downlink transmission by causing a downlink scheduling grant to be sent in the selected downlink control information (DCI) format. In the first set of DCI grant bits a first value indicates that physical downlink shared channel (PDSCH) transmission starts after N symbols for control channels and ends in the last symbol of the subframe. In the first set of DCI grant bits a second value indicates that PDSCH transmission starts from the guard period (GP) field and ends in the last symbol of the subframe.

In the case of said second set of DCI grant bits a first value indicates that PDSCH transmission starts after the physical control format information channel (PCIFCH) control symbols and ends in the last symbol of the subframe. In said second set of DCI grant bits a second value indicates that PDSCH transmission starts from the GP field and ends in the last symbol of the subframe. In said second set of DCI grant bits a third value indicates that PDSCH transmission starts after N symbols for control channels and ends in the last symbol of the subframe. Finally, in said second set of DCI grant bits a fourth value is reserved.

A method is described comprising activating new downlink grants by flexible switching, said flexible switching comprising causing a dual grant of downlink resources to be sent wherein the dual grant comprises a legacy grant and a new format grant. The method may further comprise receiving an acknowledge/negative acknowledge (ACK/NACK) signal corresponding to the new format grant, after which the method comprises using only the new format grant for scheduling the flexible switching capable UE until a next change of frame structure. The method may further comprise receiving an ACK/NACK signal corresponding to the legacy grant, after which the method comprises using only the legacy grant for scheduling until a next change of frame structure.

A method for activating new downlink grants by flexible switching comprises signaling a frequency shift value Af for ACK/NACK resources, indicating Af semi- statically in a broadcast system information block message, or indicating Af in a radio resource control (RRC) message. The method further comprises using legacy grants to schedule DL resources, receiving an ACK/NACK signal with resources corresponding to a frequency shift on the legacy ACK/NACK resources, and using new format grant resources for scheduling until a change of frame structure.

Another method comprises activating new downlink resource grants by flexible switching, said flexible switching comprising causing a frequency shift Af for deriving ACK/NACK resources to be received on one of broadcast SIB message or RRC message. One of a legacy or new format resource grant is received to be the newly introduced resource. Readiness for new frame configuration is confirmed by causing an ACK/NACK signal to be sent using resources associated with the current resources with a Af frequency shift. Once the ACK/NACK signal is sent, the method calls for using the newly introduced resources, either legacy or new format, until the next change of frame structure.

An apparatus is described comprising at least a processor having or in

communication with a memory having stored computer readable instructions, said instructions when executed by said processor causing the apparatus to perform: selecting a downlink control information (DO) format from one of: at least a first set of DCI bits to schedule a downlink transmission and a second set of DCI bits to schedule a downlink transmission; and configuring a downlink transmission by causing a downlink scheduling grant to be sent in the selected downlink control information (DCI) format. In the first set of DCI grant bits a first value indicates that physical downlink shared channel (PDSCH) transmission starts after N symbols for control channels and ends in the last symbol of the subframe. In said first set of DCI grant bits a second value indicates that PDSCH transmission starts from the guard period (GP) field and ends in the last symbol of the subframe.

In the case of said second set of DCI grant bits a first value indicates that PDSCH transmission starts after N symbols for control channels and ends in the last symbol of the subframe. In said second set of DCI grant bits a second value indicates that PDSCH transmission starts from the GP field and ends in the last symbol of the subframe. In said second set of DCI grant bits a third value indicates that PDSCH transmission starts after N symbols for control channels and ends in the last symbol of the sub frame. Finally, in said second set of DCI grant bits a fourth value is reserved.

In another embodiment is an apparatus comprising at least a processor having or in communication with a memory having stored computer readable instructions, said instructions when executed by said processor causing the apparatus to perform: activating new downlink grants by flexible switching, said flexible switching comprising, causing a dual grant of downlink resources to be sent wherein the dual grant comprises a legacy grant and a new format grant. The apparatus may further comprise instructions causing the apparatus to perform receiving an acknowledge/negative acknowledge (ACK/NACK) signal corresponding to the new format grant and using only the new format grant for scheduling the flexible switching capable UE until a next change of frame structure. The apparatus further comprises instructions causing the apparatus to perform receiving an ACK/NACK signal corresponding to the legacy grant and using only the legacy grant for scheduling until a next change of frame structure.

In another embodiment is an apparatus comprising: at least a processor having or in communication with a memory having stored computer readable instructions, said instructions when executed by said processor causing the apparatus to perform: activating new downlink grants by flexible switching, said flexible switching comprising, signaling a frequency shift value Af for ACK/NACK resources. The apparatus further comprises instructions causing the apparatus to perform indicating Af semi-statically in a broadcast system information block message, or indicating Af in a radio resource control (RRC) message. The apparatus may perform using legacy grants to schedule DL resources, receiving an ACK/NACK signal with resources corresponding to a frequency shift on the legacy ACK/NACK resources, and using new format grant resources for scheduling until a change of frame structure.

A further embodiment is an apparatus comprising at least a processor having or in communication with a memory having stored computer readable instructions, said instructions when executed by said processor causing the apparatus to perform: activating new downlink resource grants by flexible switching, said flexible switching comprising causing a frequency shift Af for deriving ACK/NACK resources to be received on one of broadcast SIB message or RRC message, and causing one of a legacy or new format resource grant to be received to become the newly introduced resource. The apparatus may further comprise instructions causing the apparatus to perform confirming readiness for new frame configuration by causing an ACK/NACK signal to be sent using resources associated with the current resources with a Af frequency shift. Further instructions call for using the newly introduced resources, either legacy or new format, until the next change of frame structure.

In a different embodiment is a computer program product comprising a non- transitory computer readable medium having stored therein computer coded instructions which, when executed by a processor, cause an apparatus to perform selecting a downlink control information (DO) format from one of: at least a first set of DCI bits to schedule a downlink transmission and a second set of DCI bits to schedule a downlink transmission; and configuring a downlink transmission by causing a downlink scheduling grant to be sent in the selected downlink control information (DO) format. The computer program product further comprises instructions wherein in said first set of DCI grant bits a first value indicates that physical downlink shared channel (PDSCH) transmission starts after N symbols for control channels and ends in the last symbol of the subframe, and wherein in said first set of DCI grant bits a second value indicates that PDSCH transmission starts from the guard period (GP) field and ends in the last symbol of the subframe.

The computer program product may further comprise instructions wherein in said second set of DCI grant bits a first value indicates that PDSCH transmission starts after N symbols for control channels and ends in the last symbol of the subframe, a second value indicates that PDSCH transmission starts from the GP field and ends in the last symbol of the subframe, a third value indicates that PDSCH transmission starts after N symbols for control channels and ends in the last symbol of the subframe, and a fourth value is reserved.

In another computer program product embodiment, a non-transitory computer readable medium has stored therein computer coded instructions which, when executed by a processor, cause an apparatus to perform: activating new downlink grants by flexible switching, said flexible switching comprising, causing a dual grant of downlink resources to be sent wherein the dual grant comprises a legacy grant and a new format grant. The computer program product further comprises instructions causing the apparatus to perform receiving an acknowledge/negative acknowledge (ACK/NACK) signal corresponding to the new format grant and using only the new format grant for scheduling the flexible switching capable UE until a next change of frame structure. The computer program product further comprises instructions causing the apparatus to alternatively perform receiving an ACK/NACK signal corresponding to the legacy grant and using only the legacy grant for scheduling until a next change of frame structure. In another embodiment is a computer program product comprising a non- transitory computer readable medium having stored therein computer coded instructions which, when executed by a processor, cause an apparatus to perform activating new downlink grants by flexible switching, said flexible switching comprising, signaling a frequency shift value Af for ACK/NACK resources, indicating Af semi-statically in a broadcast system information block message, or indicating Af in a radio resource control (RRC) message. The computer program product further comprises instructions causing the apparatus to perform using legacy grants to schedule DL resources, or alternatively receiving an ACK/NACK signal with resources corresponding to a frequency shift on the legacy ACK/NACK resources, and using new format grant resources for scheduling until a change of frame structure.

Another computer program product embodiment comprises a non-transitory computer readable medium having stored therein computer coded instructions which, when executed by a processor, cause an apparatus to perform activating new downlink resource grants by flexible switching, said flexible switching comprising causing a frequency shift Af for deriving ACK/NACK resources to be received on one of broadcast SIB message or RRC message, and causing one of a legacy or new format resource grant to be received to become the newly introduced resource. The computer program product may further comprise instructions causing the apparatus to perform confirming readiness for new frame configuration by causing an ACK/NACK signal to be sent using resources associated with the current resources with a Af frequency shift. Further instructions call for using the newly introduced resources, either legacy or new format, until the next change of frame structure.

Another different embodiment may be an apparatus comprising: means for selecting a downlink control information (DCI) format from one of: at least a first set of DCI bits to schedule a downlink transmission and a second set of DCI bits to schedule a downlink transmission; and means for configuring a downlink transmission by causing a downlink scheduling grant to be sent in the selected downlink control information (DO) format. Wherein, for this apparatus, in said first set of DCI grant bits a first value indicates that physical downlink shared channel (PDSCH) transmission starts after N symbols for control channels and ends in the last symbol of the subframe, and wherein in said first set of DCI grant bits a second value indicates that PDSCH transmission starts from the guard period (GP) field and ends in the last symbol of the subframe.

In another version of the apparatus, in said second set of DCI grant bits a first value indicates that PDSCH transmission starts after N symbols for control channels and ends in the last symbol of the subframe, a second value indicates that PDSCH transmission starts from the GP field and ends in the last symbol of the subframe, a third value indicates that PDSCH transmission starts after N symbols for control channels and ends in the last symbol of the subframe, and a fourth value is reserved.

In another embodiment is an apparatus comprising: means for activating new downlink grants by flexible switching, said flexible switching comprising, means for causing a dual grant of downlink resources to be sent wherein the dual grant comprises a legacy grant and a new format grant. The apparatus may further comprise means for receiving an acknowledge/negative acknowledge (ACK/NACK) signal corresponding to the new format grant and means for using only the new format grant for scheduling the flexible switching capable UE until a next change of frame structure. The apparatus may alternatively comprise means for receiving an ACK/NACK signal corresponding to the legacy grant, and means for using only the legacy grant for scheduling until a next change of frame structure.

Another apparatus comprises: means for activating new downlink grants by flexible switching, said flexible switching comprising, means for signaling a frequency shift value Af for ACK/NACK resources. This apparatus may comprise means for indicating Αΐ semi-statically in a broadcast system information block message, or means for indicating Af in a radio resource control (RRC) message. It may further comprise means for using legacy grants to schedule DL resources, means for receiving an ACK/NACK signal with resources corresponding to a frequency shift on the legacy ACK/NACK resources, and means for using new format grant resources for scheduling until a change of frame structure.

Another embodiment is an apparatus comprising: means for activating new downlink resource grants by flexible switching, said flexible switching comprising causing a frequency shift Af for deriving ACK/NACK resources to be received on one of broadcast SIB message or RRC message. The apparatus comprises means for receiving one of a legacy or new format resource grant to be the newly introduced resource. Readiness for new frame configuration is confirmed by means for causing an ACK/NACK signal to be sent using resources associated with the current resources with a Af frequency shift. Once the ACK/NACK signal is sent, the apparatus further comprises means for using the newly introduced resources, either legacy or new format, until the next change of frame structure.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Having thus described 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:

Fig. 1 is a schematic illustration of a special subframe as presently specified for

LTE.

Fig. 2 is a schematic drawing of a generalized wireless communications network. Fig. 3 is a schematic block drawing of an apparatus that may be embodied by a mobile terminal or an access point and may be specifically configured in accordance with an example embodiment of the present invention.

Fig. 4 is a schematic drawing of a special subframe as modified in one embodiment.

Fig. 5 is a schematic drawing of a new signaling protocol according to a dual grant with acknowledgement/non-acknowledgement embodiment including a modified special subframe.

Fig. 6 is a schematic drawing of an alternative embodiment of signaling protocol for a single grant with acknowledge/non-acknowledge signaling with modified subframe.

Fig. 7 is a flow chart of a method according to a first embodiment.

Fig. 8 is a flow chart of a method according to a second embodiment.

Fig. 9 is a flow chart of a method according to a third embodiment.

Fig. 10 is a flow chard of a method according to a fourth embodiment.

DETAILED DESCRIPTION

Various embodiments 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.

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.

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.

Although the method, apparatus and computer program product of example embodiments of the present invention may be implemented in a variety of different systems, one example of such a system is shown in Fig. 2, which includes a mobile terminal 8 that is capable of communication with a network 6 (e.g., a core network) via, for example, an access point 2 (AP). While the network may be configured in accordance with Global System for Mobile communications (GSM) / Enhanced Data rates for Global Evolution (EDGE) Radio Access Network (GERAN), the network may employ other mobile access mechanisms such as a Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN), Long Term Evolution (LTE), LTE-Advanced (LTE-A), wideband code division multiple access (W-CDMA), CDMA2000, and/or the like. The embodiments of the present invention may also be implemented in future LTE based technologies, such as LTE-A and subsequently developed mobile networks. The network 6 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 base stations, such as one or more Base Transceiver Stations (BTSs) and Base Station Controllers (BSCs), node Bs, evolved node Bs (eNBs), access points (AP), relay nodes or the like (all of which being hereinafter generically referenced as an access point (AP)), each of which may serve a coverage area divided into one or more cells. For example, the network may include one or more cells, including, for example, the AP 2, each of which may serve a respective coverage area. The serving cell could be, for example, part of one or more cellular or mobile networks or public land mobile networks (PLMNs). In turn, other devices such as processing devices (e.g., personal computers, server computers or the like) may be coupled to the mobile terminal and/or the second communication device via the network.

The mobile terminals 8 may be in communication with each other or other devices via the network 6. In some cases, each of the mobile terminals may include an antenna or antennas for transmitting signals to and for receiving signals from a base station. In some example embodiments, the mobile terminal 8, also known as a client device, may be a mobile communication device or user equipment (UE) such as, for example, a mobile telephone, portable digital assistant (PDA), pager, laptop computer, tablet computer, or any of numerous other hand held or portable communication devices, computation devices, content generation devices, content consumption devices, universal serial bus (USB) dongles, data cards or combinations thereof. As such, the mobile terminal 8 may include one or more processors that may define processing circuitry either alone or in combination with one or more memories. The processing circuitry may utilize instructions stored in the memory to cause the mobile terminal to operate in a particular way or execute specific functionality when the instructions are executed by the one or more processors. The mobile terminal 8 may also include communication circuitry and corresponding hardware/software to enable communication with other devices and/or the network 6.

Referring now to Fig. 3, an apparatus 20 that may be embodied by or otherwise associated with a mobile terminal 8 (a cellular phone, a personal digital assistant (PDA), smartphone, tablet computer or the like) or an AP 2 may include or otherwise be in communication with a processor 22, a memory device 24, a communication interface 28, and a user interface 30.

In some example embodiments, the processor 22 (and/or co-processors or any other processing circuitry assisting or otherwise associated with the processor) may be in communication with the memory device 24 via a bus for passing information among components of the apparatus 20. The memory device 24 may include, for example, one or more non-transitory volatile and/or non-volatile memories. In other words, for example, the memory device 24 may be an electronic storage device (e.g., a computer readable storage medium) comprising gates configured to store data (e.g., bits) that may be retrievable by a machine (e.g., a computing device like the processor). The memory device 24 may be configured to store information, data, content, applications, instructions, or the like for enabling the apparatus to carry out various functions in accordance with an example embodiment of the present invention. For example, the memory device could be configured to buffer input data for processing by the processor. Additionally or alternatively, the memory device 24 could be configured to store instructions for execution by the processor 22.

As noted above, the apparatus 20 may, in some embodiments, be embodied by a mobile terminal 8 or an AP 2. However, in some embodiments, the apparatus may be embodied as a chip or chip set. In other words, the apparatus 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 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.

The processor 22 may be embodied in a number of different ways. For example, the processor may be embodied as one or more of various hardware processing means such as a coprocessor, a microprocessor, a controller, a digital signal processor (DSP), a processing element with or without an accompanying DSP, or various other processing circuitry including integrated circuits such as, for example, an ASIC (application specific integrated circuit), an FPGA (field programmable gate array), a microcontroller unit (MCU), a hardware accelerator, a special-purpose computer chip, or the like. As such, in some embodiments, the processor may include one or more processing cores configured to perform independently. A multi-core processor may enable multiprocessing within a single physical package. Additionally or alternatively, the processor may include one or more processors configured in tandem via the bus to enable independent execution of instructions, pipelining and/or multithreading. In the embodiment in which the apparatus 20 is embodied as a mobile terminal 8, the processor may be embodied by the processor of the mobile terminal.

In an example embodiment, the processor 22 may be configured to execute instructions stored in the memory device 24 or otherwise accessible to the processor. Alternatively or additionally, the processor may be configured to execute hard coded functionality. As such, whether configured by hardware or software methods, or by a combination thereof, the processor may represent an entity (e.g., physically embodied in circuitry) capable of performing operations according to an embodiment 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 algorithms and/or operations described herein when the instructions are executed. However, in some cases, the processor may be a processor of a specific device (e.g., a mobile terminal 8) configured to employ an embodiment of the present invention by further configuration of the processor by instructions for performing the algorithms and/or operations described herein. The processor may include, among other things, a clock, an arithmetic logic unit (ALU) and logic gates configured to support operation of the processor.

Meanwhile, the communication interface 28 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 and/or any other device or module in communication with the apparatus 20. In this regard, the communication interface may include, for example, an antenna (or multiple antennas) and supporting hardware and/or software for enabling communications with a wireless communication network. Additionally or alternatively, the communication interface may include the circuitry for interacting with the antenna(s) to cause transmission of signals via the antenna(s) or to handle receipt of signals received via the antenna(s). In order to support multiple active connections simultaneously, such as in conjunction with a digital super directional array (DSD A) device, the communications interface of one embodiment may include a plurality of cellular radios, such as a plurality of radio front ends and a plurality of base band chains. In some environments, the communication interface may alternatively or also support wired communication. As such, for example, the communication interface may include a communication modem and/or other hardware/software for supporting communication via cable, digital subscriber line (DSL), universal serial bus (USB) or other mechanisms.

In some example embodiments, such as instances in which the apparatus 20 is embodied by a mobile terminal 8, the apparatus may include a user interface 30 that may, in turn, be in communication with the processor 22 to receive an indication of a user input and/or to cause provision of 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(s), touch areas, soft keys, a microphone, a speaker, or other input/output mechanisms. Alternatively or additionally, the processor may comprise user interface circuitry configured to control at least some functions of one or more user interface elements such as, for example, a speaker, ringer, microphone, display, and/or the like. The processor and/or user interface circuitry comprising the processor may be configured to control one or more functions of one or more user interface elements through computer program instructions (e.g., software and/or firmware) stored on a memory accessible to the processor (e.g., memory device and/or the like).

The next generation UE can use the remaining guard period (GP) and uplink pilot time slot (UpPTS) fields to receive a DL data transmission in the case of switching from a special subframe (SSF) to a normal DL SF. This would require new DL grants with one or more bits to indicate the starting point and duration of a physical downlink shared channel (PDSCH) transmission. The following mechanisms to activate/deactivate the usage of new DL grants are designed to solve an ambiguity issue during the UL-DL switching period while retaining the minimum blind decoding complexity and signaling overhead.

DL grants with new DCI formats When a SSF configured by the SIB l is reconfigured as a normal DL SF via new UL-DL switching signaling, new DL grant signaling with one or more bits would be used for the next generation UE. First and second sets of bits, perhaps numbering one or more bits in each, may be added to the existing DL scheduling signaling to indicate the starting point and duration of a PDSCH transmission in the subframe in the time domain of the DL subframe (indicated as SSF by SIBl) for the next generation UE. The next generation UE is aware of the frame structure configuration from SIBl and the latest frame reconfigured by the new UL-DL switching signaling. Example sets of DL grant bits are provided below but the possibilities are not limited to these examples.

Option 1: one more bit for DL Grant supposing the same power applied over the whole subframe.

One bit could be used to indicate: (see Table 3)

"1 ": PDSCH transmission is started after the first N symbols for control channels, and ended in the last symbol of the subframe, which is same as the normal DL subframe transmission;

"0": PDSCH transmission is started from GP field and ended in the last symbol of the subframe, e.g., GP and UpPTS fields.

Table 3. 1 -bit resou rce mappi ng indicator for PDSCH

Option 2: two more bits for DL Grant supposing different power applied on the

DwPTS field and GP/UpPTS field. Two bits could be used to indicate DL grants: (see Table 4)

"11": PDSCH transmission is started after the control region indicated by the physical control format information channel (PCFICH), and ended in the last symbol of the subframe, which is same as the normal DL suframe transmission;

"01": PDSCH transmission is started from GP field and ended in the last symbol of the subframe ( e.g., GP and UpPTS fields);

"10": PDSCH transmission is started after the control region indicated by

PCFICH, and ended in the last symbol of DwPTS field;

"00": Reserved.

Table 4. 2-bit resou rce mappi ng indicator for PDSCH

DL grants with new PCI formats for option 2

Some examples for option 2 are illustrated in Figure 4. The legacy UEs and the next generation UEs would monitor the SIBl message to discover the TDD UL-DL configuration. The new switching signaling (L1/L2/L3 signaling) would support adaptive UL-DL switching, which could be periodic or event triggered signaling. It will only be known to the next generation UEs.

Referring to Fig. 4, if frame configuration 0 has been configured for all UEs by an SIBl indication, when switching to the new frame configuration (e.g, configuration 5) via the new signaling, the next generation UEs (#1 ,#2,#3 and #4) would monitor the new DL grants with two more bits, whereas legacy UEs (e.g., UE #0) would monitor only the legacy DL grants. In this case,

PDSCH transmission for legacy UE is scheduled only in the DwPTS field

(excluding the first few symbols for the control channels);

For next generation UEs #1-4, the new DL grants would indicate the starting point and duration of PDSCH transmission. For example (in Fig.

4),

^■ UE #1 is only scheduled on DwPTS part indicated by "10".

^■ UE #2 and UE #3 are only scheduled in GP and UpPTS fields indicated by "01".

^■ UE #4 is scheduled over the whole subframe period (excluding the control region) as indicated by "1 1".

Activation/deactivation of the new DL grants: During a UL-DL switching period, there is an ambiguity issue. The base station (BS) reconfigures the frame structure via the UL-DL switching signal but is not sure whether UE is ready. The unreliability of UE reception and uncertainty of UE processing time creates the uncertainty. It results in an issue of when the new DL grants may be used.

Option 1: Dual-Grant with ACK NACK differentiation

Referring to Fig. 5, during the ambiguity period, a dual-grant (the new format grant 502 and the legacy grant 504) would be sent simultaneously from eNB 500 to UE 501 to schedule the same resources for DL transmission. When UE detects the first legacy grant 508, it sends an ACK/NACK to eNB using the resources associated with the legacy grant 507. Once UE detects the new grant 510 it sends an ACK/NACK 505 to eNB using the newly introduced grant 502. Based on the UE's ACK/NACK feedback resources used, eNB can discern whether UE is ready for the new frame configuration (e.g., capability to decode the newly introduced grant or not).

As illustrated in Figure 5, the procedure can be described as below: Step 1: During the ambiguity period Ά', eNB would use both legacy grants 502 and new format grants 504 to schedule the same DL resources for the next generation UEs. To reduce the blind decoding complexity, the legacy grants can be located in the common search space whereas the new format grants can be in the user-specific search space.

Step 2: UE tries to decode both grants 502, 504 once UE is ready for the new configuration. Once UE finds the newly introduced DL grant (e.g., the new format grant 510 in case of SSF->DL_SF switching ambiguity period Ά', and the legacy format grant 522 in the case of DL_SF->SSF switching ambiguity period 'B'), UE provides an ACK/NACK with the resources associated with the newly introduced grant (510 in period A; 522 in B). After that, UE only decodes the new introduced grant instead of both of them.

Step 3: when eNB receives the ACK/NACK corresponding to the new introduced grant (510 or 522), eNB knows that UE is ready for reconfiguration. After that, eNB would only use the newly introduced grant for scheduling until the change of the frame structure.

This option can solve the ambiguity issue. However, it would send the duplicated grants with two formats during the ambiguity period, which may waste the control channels resources. In the case of a small cell scenario (a typical scenario for flexible TDD switching), the cost may be acceptable due to the relatively fewer active users.

Option 2: Single-Grant with ACK/NAK resource shifting

eNB would indicate a frequency shift (Δί) for ACK/NACK resources, associated with the flexible switching signaling or transmitted via RRC/broadcast signaling. After base station (eNB) flexible switching, UE can provide the feedback on the legacy resources if UE is not ready for reconfiguration or on the new ones with a frequency shift (Δί) if UE is ready. Depending on the ACK/NACK feedback resources used by UE, eNB can determine whether UE is ready for the new configuration.

As illustrated in Figure 6, the procedure can be described as follows:

Step 1 : During the UL => DL reconfiguration (SSF=>DL_SF), eNB 640 would signal a frequency shift value (Δί) 650 for ACK/NACK resources so that UE can provide the feedback on the legacy resources 604 or new resources 606 depending on whether UE is ready for UL=>DL reconfiguration. Alternatively, Af 650 could be indicated semi- statically in the broadcast message (e.g., system information block (SIB)) message or

RRC message to reduce the signaling overhead.

Step 2: During the ambiguity period Ά', eNB would use the legacy grants 602 to schedule the DL resources for the next generation UEs when switching from SSF-

>DL_SF.

Step 3: UE 601 attempts to decode the legacy grants. Once UE 601 is ready for the new configuration, UE would use the corresponding 'new grant' ACK/NACK resources 606 with a frequency shift (Δί) to provide the feedback. Otherwise, UE would just use the normal ACK/NACK resources 604 for feedback.

Step 4: During ambiguity period 'B', when eNB receives the ACK/NACK corresponding to a frequency shift on the legacy resources 624, eNB would know that UE is ready for DL => UL reconfiguration. Until then, eNB would use the new format grant 622 for scheduling until the change of the frame structure.

This option can also solve the ambiguity issue. It would require the double reservation of ACK/NACK resources and an additional signaling parameter to indicate Af. Compared to option 1 , it has the lower signaling cost with no need of duplicated grants.

Referring to Fig. 7, there is illustrated a first embodiment of a method according to this description. After selecting a DCI format, downlink grants may be made according to two potential variants for configuration. The downlink subframe is configured in a selected downlink control information (DCI) format 701. A one-bit downlink resource grant 703 may be provided wherein a first value of the one -bit field (either 1 or 0) may indicate 707 that the PDSCH extends (see Table 3) from the last control bits to the last subframe symbol (that is, DwPTS, GP, and UpPTS). The second value (the other of 1 or 0) 711 may indicate that PDSCH extends from the guard period to the last subframe symbol.

Alternatively, the DL grant may comprise two bits 705 in the DCI format. A first value 709 may indicate that PDSCH starts after N symbols for the control channel and extends to the last subframe symbol (see Table 3). A second value may indicate 713 that PDSCH extends from the guard period field to the last subframe symbol. A third value may indicate 715 that PDSCH starts after N symbols for the control channel and extends to the last subframe symbol. A fourth value of the two-bit field 717 may be reserved.

Referring to Fig. 8, a method for activating new downlink grants with flexible switching is illustrated 801. In this method, eNB sends dual resource grants 803, a legacy grant and a new format grant, to next generation UE. Once UE finds the new format resource grant (when switching from SSF=>DL_SF) it sends an ACK/NACK signal 805 corresponding to the new format resources grant. Once the ACK/NACK is received, eNB uses only the new format resources 809 for flexible switching UE until the next frame structure change.

For the switch from DL_SF=>SSF, eNB sends dual resource grants 803 and, when UE finds the legacy resource, eNB receives an ACK/NACK from UE 807 corresponding to the legacy resource grant. Once the ACK/NACK signal is received, only the legacy resource grant is used 811 until the next frame structure change.

Fig. 9 illustrates an alternative single resource grant method for activating a new downlink grant 901 with flexible switching. In this method, eNB signals 903 a frequency shift Af for ACK/NACK resources. The Af indication may be sent semi-statically in a broadcast SIB message 905 or it may be indicated in an RRC message 911. Switching from SSF=>DL_SF eNB uses legacy grant to schedule the DL resources 913. When UE is ready to assume the new configuration, eNB receives an ACK/NACK signal shifted by Af on legacy ACK/NACK resources 915. Once the ACK/NACK is received, eNB uses only new format DL grant resources until the next change of frame structure 917. The process works in reverse for switching back to SSF.

The steps listed for each of Figs. 7-9 may be performed in an apparatus comprising means for performing each of the listed functions. Said apparatus may be embodied by a serving cell, or access point 2 (Fig. 2) to the network 6. The access point 2 may take the form of an apparatus 20 comprising a processor 22, a memory 24 and communications interface 28. The means for performing the listed functions includes, for example, (Fig. 3) a processor 22, a memory 24 containing computer coded instructions for carrying out the functions, and a communications interface 28 for sending resource grants to the UE and receiving ACK/NACK signals and other information in return.

Fig. 10 illustrates the method for single grant as implemented in UE 1001. A frequency shift Af for deriving ACK/NACK resources is received either in a broadcast SIB message 1003 or in the RRC message 1005. Taking the switch from SSF=>DL_SF and back to DL_SF=>SSF into account, UE receives one of a legacy or new format resource grant 1007 as the newly introduced resource. UE signals its readiness to adopt a new configuration by sending an ACK/NACK 1009 on the current resource with the frequency shift Af. Once UE accepts the new configuration, it uses only the newly introduced resource 101 1 until the next frame structure change.

The steps listed for Fig. 10 may be performed in an apparatus comprising means for performing each of the listed functions. Said apparatus may be embodied by a mobile terminal 8 (Fig. 2) in communication with an access point 2 to the network 6. The mobile terminal may comprise (Fig. 3) a processor 22, a memory 24 and communications interface 28. The means for performing the listed functions includes, for example, a processor 22, a memory 24 containing computer coded instructions for carrying out the functions, and a communications interface 28 for receiving resource grants from the access point and sending ACK/NACK signals and other information in return.

As described above, Figures 7-10 are flowcharts of a method, apparatus and program product according to example embodiments of the 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 device 24 of an apparatus 20 employing an embodiment of the present invention and executed by a processor 22 in 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 embody a mechanism for implementing the functions specified in the flowchart blocks. These computer program instructions may also be stored in a non-transitory computer-readable storage memory (as opposed to a transmission medium such as a carrier wave or electromagnetic signal) that may direct a computer or other programmable apparatus to function in a particular manner, such that the instructions stored in the computer-readable 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 block(s). As such, the operations of Figures 7-10, 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 Figures 7-10 define an algorithm for configuring a computer or processing circuitry (e.g., processor) to perform an example embodiment. In some cases, a general purpose computer may be configured to perform the functions shown in Figures 7-10 (e.g., via configuration of the processor), thereby transforming the general purpose computer into a particular machine configured to perform an example embodiment.

Accordingly, blocks of the flowcharts support combinations of means for performing the specified functions, combinations of operations for performing the specified functions and program instructions 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 operations, or combinations of special purpose hardware and computer instructions.

The reconfiguration processes described provide several advantages for the next generation network. They offer full utilization of the resources during switching from SSF to normal DL SL. Ambiguity resolution can be accomplished with low signaling cost. There is low signaling overhead cost and latency overall. These processes cause no increase in attempts of UE blind detection. There would be only a minor impact on network specifications and implementation would be fairly simple. The processes are flexible depending on eNB scheduling. And these processes are fully testable. The following list of abbreviations and acronyms is provided as a reference for terms appearing in this description that may also appear in the claims to follow.

ACK/NACK Acknowledge/Negative acknowledge

AP Access Point

DCI Downlink Control Information

DL Downlink

DwPTS Downlink Pilot Time Slot

eNB E-UTRAN NodeB

FC Frame Configuration

GP Guard Period

LTE Long Term Evolution

PCFICH Physical Control Format Information Channel

PDCCH Physical Downlink Control Channel

PDSCH Physical Downlink Shared Channel

RRM Radio Resource Management

RSRP Radio Signal Received Power

RSRQ Radio Signal Received Quality

SF Subframe

SIB System Information Block

SSF Special Subframe

TDD Time Division Duplex

UE User Equipment

UL Uplink

UpPTS Uplink Pilot Time Slot

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. 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 comprising:

selecting a downlink control information (DCI) format from one of:

at least a first set of DCI bits to schedule a downlink transmission and a second set of DCI bits to schedule a downlink transmission; and

configuring a downlink transmission by causing a downlink scheduling grant to be sent in the selected downlink control information (DCI) format.

2. The method of claim 1 wherein in said first set of DCI grant bits a first value indicates that physical downlink shared channel (PDSCH) transmission starts after N symbols for control channels and ends in the last symbol of the subframe.

3. The method of either of claims 1 and 2 wherein in said first set of DCI grant bits a second value indicates that PDSCH transmission starts from the guard period (GP) field and ends in the last symbol of the subframe.

4. The method of claim 1 wherein in said second set of DCI grant bits a first value indicates that PDSCH transmission starts after N symbols for control channels and ends in the last symbol of the subframe.

5. The method of either of claims 1 and 4 wherein in said second set of DCI grant bits a second value indicates that PDSCH transmission starts from the GP field and ends in the last symbol of the subframe.

6. The method of any of claims 1 and 4-5 wherein in said second set of DCI grant bits a third value indicates that PDSCH transmission starts after N symbols for control channels and ends in the last symbol of the subframe.

7. The method of any of claims 1 and 4-6 wherein in said second set of DCI grant bits a fourth value is reserved.

8. A method comprising: activating new downlink grants by flexible switching, said flexible switching comprising,

causing a dual grant of downlink resources to be sent wherein the dual grant comprises a legacy grant and a new format grant.

9. The method of claim 8, further comprising:

receiving an acknowledge/negative acknowledge (ACK/NACK) signal corresponding to the new format grant.

10. The method of claim 9, further comprising:

using only the new format grant for scheduling the flexible switching capable UE until a next change of frame structure.

11. The method of claim 8, further comprising:

receiving an ACK/NACK signal corresponding to the legacy grant.

12. The method of claim 11 , further comprising:

using only the legacy grant for scheduling until a next change of frame structure.

13. A method comprising:

activating new downlink grants by flexible switching, said flexible switching comprising,

causing a frequency shift value Af for ACK/NACK resources to be signaled.

14. The method of claim 13, further comprising:

indicating Af semi-statically in a broadcast system information block (SIB) message.

15. The method of claim 13, further comprising:

indicating Af in a radio resource control (RRC) message.

16. The method of claim 13, further comprising:

using legacy grants to schedule DL resources.

17. The method of any of claims 13 to 16, further comprising:

receiving an ACK/NACK signal with resources corresponding to a frequency shift on the legacy ACK/NACK resources, and

using new format grant resources for scheduling until a change of frame structure.

18. A method comprising:

activating new downlink resource grants by flexible switching, said flexible switching comprising,

causing a frequency shift Af for deriving ACK/NACK resources to be received on one of broadcast SIB message or RRC message; and causing one of a legacy or new format resource grant to be received as a newly introduced resource.

19. The method of claim 18, further comprising:

confirming readiness for new frame configuration by causing an ACK/NACK signal to be sent using current resources with a Af frequency shift.

20. The method of claim 18, further comprising:

using newly introduced resources until a next change of frame structure.

21. An apparatus comprising:

at least a processor having or in communication with a memory having stored computer readable instructions, said instructions when executed by said processor causing the apparatus to perform:

selecting a downlink control information (DCI) format from one of:

22. The apparatus of claim 21 further comprising instructions wherein in said first set of DCI grant bits a first value indicates that physical downlink shared channel (PDSCH) transmission starts after N symbols for control channels and ends in the last symbol of the sub frame.

23. The apparatus either of claims 21 and 22 further comprising instructions wherein in said first set of DCI grant bits a second value indicates that PDSCH transmission starts from the guard period (GP) field and ends in the last symbol of the subframe.

24. The apparatus of claim 21 further comprising instructions wherein in said second set of DCI grant bits a first value indicates that PDSCH transmission starts after N symbols for control channels and ends in the last symbol of the subframe.

25. The apparatus either of claims 21 and 24 further comprising instructions wherein in said second set of DCI grant bits a second value indicates that PDSCH transmission starts from the GP field and ends in the last symbol of the subframe.

26. The apparatus any of claims 1 and 4-5 further comprising instructions wherein in said second set of DCI grant bits a third value indicates that PDSCH transmission starts after N symbols for control channels and ends in the last symbol of the subframe.

27. The apparatus any of claims 1 and 4-6 further comprising instructions wherein in said second set of DCI grant bits a fourth value is reserved.

28. An apparatus comprising:

29. The apparatus of claim 28 further comprising instructions causing the apparatus to perform:

30. The apparatus of claim 29 further comprising instructions causing the apparatus to perform:

31. The apparatus of claim 28 further comprising instructions causing the apparatus to perform:

receiving an ACK/NACK signal corresponding to the legacy grant.

32. The apparatus of claim 31 further comprising instructions causing the apparatus to perform:

33. An apparatus comprising:

causing a frequency shift value Af for ACK/NACK resources to be signaled.

34. The apparatus of claim 33 further comprising instructions causing the apparatus to perform:

indicating Af semi-statically in a broadcast system information block message.

35. The apparatus of claim 33 further comprising instructions causing the apparatus to perform:

indicating Af in a radio resource control (RRC) message.

36. The apparatus of claim 33 further comprising instructions causing the apparatus to perform:

using legacy grants to schedule DL resources.

37. The apparatus of any of claims 33 to 36 further comprising instructions causing the apparatus to perform:

38. An apparatus comprising:

39. The apparatus of claim 38 further comprising instructions causing the apparatus to perform:

40. The apparatus of claim 38 further comprising instructions causing the apparatus to perform:

using newly introduced resources until a next change of frame structure.

41. A computer program product comprising a non-transitory computer readable medium having stored therein computer coded instructions which, when executed by a processor, cause an apparatus to perform:

selecting a downlink control information (DCI) format from one of:

42. The computer program product of claim 41 further comprising instructions wherein in said first set of DCI grant bits a first value indicates that physical downlink shared channel (PDSCH) transmission starts after N symbols for control channels and ends in the last symbol of the subframe.

43. The computer program product either of claims 41 and 42 further comprising instructions wherein in said first set of DCI grant bits a second value indicates that PDSCH transmission starts from the guard period (GP) field and ends in the last symbol of the subframe.

44. The computer program product of claim 41 further comprising instructions wherein in said second set of DCI grant bits a first value indicates that PDSCH

transmission starts after N symbols for control channels and ends in the last symbol of the subframe.

45. The computer program product of either of claims 41 and 44 further comprising instructions wherein in said second set of DCI grant bits a second value indicates that PDSCH transmission starts from the GP field and ends in the last symbol of the subframe.

46. The computer program product of any of claims 41 and 44-45 further comprising instructions wherein in said second set of DCI grant bits a third value indicates that PDSCH transmission starts after N symbols for control channels and ends in the last symbol of the subframe.

47. The computer program product of any of claims 41 and 44-46 further comprising instructions wherein in said second set of DCI grant bits a fourth value is reserved.

48. A computer program product comprising a non-transitory computer readable medium having stored therein computer coded instructions which, when executed by a processor, cause an apparatus to perform: activating new downlink grants by flexible switching, said flexible switching comprising,

49. The computer program product of claim 48 further comprising instructions causing the apparatus to perform:

50. The computer program product of claim 49 further comprising instructions causing the apparatus to perform:

51. The computer program product of claim 48 further comprising instructions causing the apparatus to perform:

receiving an ACK/NACK signal corresponding to the legacy grant.

52. The computer program product of claim 51 further comprising instructions causing the apparatus to perform:

53. A computer program product comprising a non-transitory computer readable medium having stored therein computer coded instructions which, when executed by a processor, cause an apparatus to perform: activating new downlink grants by flexible switching, said flexible switching comprising,

causing a frequency shift value Af for ACK/NACK resources to be signaled.

54. The computer program product of claim 53 further comprising instructions causing the apparatus to perform:

indicating Af semi-statically in a broadcast system information block message.

55. The computer program product of claim 53 further comprising instructions causing the apparatus to perform:

indicating Af in a radio resource control (RRC) message.

56. The computer program product of claim 53 further comprising instructions causing the apparatus to perform:

using legacy grants to schedule DL resources.

57. The computer program product of any of claims 53 to 56 further comprising instructions causing the apparatus to perform:

58. A computer program product comprising a non-transitory computer readable medium having stored therein computer coded instructions which, when executed by a processor, cause an apparatus to perform: activating new downlink resource grants by flexible switching, said flexible switching comprising,

causing a frequency shift Af for deriving ACK/NACK resources to be received on one of broadcast SIB message or RRC message; and

causing one of a legacy or new format resource grant to be received as a newly introduced resource.

59. The computer program product of claim 58 further comprising instructions causing the apparatus to perform:

60. The computer program product of claim 58 further comprising instructions causing the apparatus to perform:

using newly introduced resources until a next change of frame structure.

61. An apparatus comprising:

means for selecting a downlink control information (DO) format from one of: at least a first set of DCI bits to schedule a downlink transmission and a second set of DCI bits to schedule a downlink transmission; and

means for configuring a downlink transmission by causing a downlink scheduling grant to be sent in the selected downlink control information (DCI) format.

62. The apparatus of claim 61 wherein in said first set of DCI grant bits a first value indicates that physical downlink shared channel (PDSCH) transmission starts after N symbols for control channels and ends in the last symbol of the subframe.

63. The apparatus of either of claims 61 and 62 wherein in said first set of DCI grant bits a second value indicates that PDSCH transmission starts from the guard period (GP) field and ends in the last symbol of the subframe.

64. The apparatus of claim 61 wherein in said second set of DCI grant bits a first value indicates that PDSCH transmission starts after N symbols for control channels and ends in the last symbol of the subframe.

65. The apparatus of either of claims 61 and 64 wherein in said second set of DCI grant bits a second value indicates that PDSCH transmission starts from the GP field and ends in the last symbol of the subframe.

66. The apparatus of any of claims 61 and 64-65 wherein in said second set of DCI grant bits a third value indicates that PDSCH transmission starts after N symbols for control channels and ends in the last symbol of the subframe.

67. The apparatus of any of claims 61 and 64-66 wherein in said second set of DCI grant bits a fourth value is reserved.

68. An apparatus comprising:

means for activating new downlink grants by flexible switching, said flexible switching comprising,

means for causing a dual grant of downlink resources to be sent wherein the dual grant comprises a legacy grant and a new format grant.

69. The apparatus of claim 68 further comprising:

means for receiving an acknowledge/negative acknowledge (ACK/NACK) signal corresponding to the new format grant.

70. The apparatus of claim 69 further comprising:

means for using only the new format grant for scheduling the flexible switching capable UE until a next change of frame structure.

71. The apparatus of claim 68 further comprising:

means for receiving an ACK/NACK signal corresponding to the legacy grant.

72. The apparatus of claim 71 further comprising:

means for using only the legacy grant for scheduling until a next change of frame structure.

73. An apparatus comprising:

means for causing a frequency shift value Af for ACK/NACK resources to be signaled.

74. The apparatus of claim 73 further comprising:

means for indicating Af semi-statically in a broadcast system information block message.

75. The apparatus of claim 73 further comprising:

means for indicating Af in a radio resource control (RRC) message.

76. The apparatus of claim 73 further comprising:

means for using legacy grants to schedule DL resources.

77. The apparatus of any of claims 73 to 76 further comprising:

means for receiving an ACK/NACK signal with resources corresponding to a frequency shift on the legacy ACK/NACK resources, and

means for using new format grant resources for scheduling until a change of frame structure.

78. An apparatus comprising:

means for activating new downlink resource grants by flexible switching, said flexible switching comprising,

means for causing a frequency shift Af for deriving ACK/NACK resources to be received on one of broadcast SIB message or RRC message; and

means for causing one of a legacy or new format resource grant to be received as a newly introduced resource.

79. The apparatus of claim 78 further comprising:

means for confirming readiness for new frame configuration by causing an ACK/NACK signal to be sent using current resources with a Af frequency shift.

80. The apparatus of claim 78 further comprising:

means for using newly introduced resources until a next change of frame structure.

81. The apparatus of any of claims 38-40 wherein the apparatus is a portable mobile terminal.

82. The apparatus of any of claims 38-40, wherein the apparatus is configured for use in Long Term Evolution time division duplex communication.

83. The apparatus of any of claims 38-40 is a mobile terminal further comprising: user interface circuitry; and

user interface software configured to facilitate control of at least some functions of the mobile terminal.