WO2014166058A1

WO2014166058A1 - Adapting inter-band harq to support flexible tdd subframe configuration

Info

Publication number: WO2014166058A1
Application number: PCT/CN2013/073960
Authority: WO
Inventors: Jing HAN; Chunyan Gao; Haiming Wang; Lili Zhang; Wei Hong
Original assignee: Broadcom Corp
Current assignee: Broadcom Corp
Priority date: 2013-04-09
Filing date: 2013-04-09
Publication date: 2014-10-16
Anticipated expiration: 2015-10-09

Abstract

Hybrid automatic repeat request (HARQ) timing rules for carrier aggregation network deployments, where a primary and a secondary cell simultaneously utilize different time division duplex (TDD) uplink-downlink (UL-DL) subframe configurations, are re-used for flexible TDD UL-DL subframe configuration network deployments in which a same cell changes the TDD UL-DL configuration between first and second configuration periods. This re-use is accomplished in one embodiment by mapping a data radio resource in the first configuration period to a feedback radio resource in the second configuration period according to the re-used HARQ timing rules. Depending on uplink/downlink and the perspective is of the mobile device or the network, the mapped feedback radio resource is used to search for or to send HARQ feedback. Non-limiting examples re-use self-scheduling and cross-scheduling rules as well as regard the configuration in the first/second configuration period as the scheduled/scheduling cell of the HARQ timing rules.

Description

ADAPTING INTER-BAND HARQ TO SUPPORT FLEXIBLE TDD

SUBFRAME CONFIGURATION

TECHNICAL FIELD:

[0001 ] The exemplary and non-limiting embodiments of this invention relate generally to wireless communication systems, methods, devices and computer programs and, more specifically, relate to mapping acknowledgement/negative acknowledgement feedback from a radio resource to which that feedback correlates when the system uses flexibly configured uplink-downlink subframe configurations.

BACKGROUND:

[0002] Hybrid automatic repeat request (HARQ) techniques allow for the recipient of a wireless message to send an acknowledgement (ACK) to the sender of that message without the need for added control signaling to schedule the ACK. This is because there is a known mapping from the radio resource that carried the message to the radio resource in which the ACK is sent. So for example when a user equipment (UE) is configured with a radio frame arranged with a particular mixture of uplink (UL) and downlink (DL) sub frames such as the three examples shown at Figure 5, there is a known mapping from a DL message the UE receives in subframe 0 for example to some other subframe in which the UE is to send its HARQ feedback. In many systems that employ HARQ processes a negative acknowledgement (NACK) is effected by failure of the message recipient to send an ACK On time', in the mapped radio resource (or failure of the message sender to receive an ACK on time), and it is conventional in the wireless arts to refer to this absence of an ACK as 'sending' a NACK.

[0003] Allowing for asymmetric UL-DL allocations has been claimed as one benefit of deploying time division duplex (TDD) system. The asymmetric resource allocation in the TDD version of the evolved Universal Terrestrial Radio Access system (E-UTRA, sometimes also known as long term evolution LTE of UTRA) is realized by providing seven different semi-statically configured uplink-downlink configurations which are set forth at the Third Generation Partnership Project (3 GPP) TS 36.213 vl2.2.0 (2013-03). These allocations can provide between 40% and 90% DL subframes. In current LTE deployment, the same TDD configuration in each cell is assumed since otherwise interference between UL and DL needs to be considered (including both base station-to-base station and UE-to-UE interference).

[0004] In a local area (LA) network, due to small number of active UEs per cell the traffic situation may fluctuate frequently, and TDD reconfiguration to adapt to the traffic had been expected to provide improved resource efficiency and provide power saving. A problem arises when the UL/DL subframe configuration changes. Assuming as an example that the underlying data message is UL from the UE to the network, the mapped HARQ feedback subframe must of course be DL in order for the network to send its ACK to the UE. As a more specific example at Figure 1 , in the first radio frame 101 a message sent in UL subframe #2 can map to DL subframe #9 of that same first radio frame 101 for proper HARQ feedback. But when the UL/DL configuration changes in consecutive radio frames the HARQ subframe mapping that crosses into the next radio frame will not always match to the proper direction subframe when the UL/DL configuration changes.

[0005] An example of this is depicted at Figure 1 in which the time division duplex (TDD) UL/DL configuration 0 in frame 102 follows UL/DL configuration 1 in frame 101. These are two of the seven UL/DL configurations in use for E-UTRA networks (E-UTRANs). An UL message in subframe #8 of frame 101 would under conventional HARQ rules map to subframe #4 of the next subsequent subframe, but in Figure 1 that also is an UL subframe and so the network cannot sent its HARQ feedback there. The next best option is for the network to send its ACK for subframe #8 of frame 101 in DL subframe #5 of the next subsequent frame 102.

[0006] Dynamically changing the TDD UL/DL subframe configuration is now proposed for further advances of LTE. The following are relevant in this regard.

• document RP- 101450 entitled Study on further Enhancements to LTE TDD for DL-UL Interference Management and Traffic Adaptation [3GPP RAN#50 ] shows agreement for flexible TDD where each cell can (re)configure independent TDD configuration based on traffic in its own cell and proposing to study interference mitigation in multi-cell scenarios. • document RP- 120693 entitled [3 GPP RAN#56 ] closes a study item for flexible TDD with agreement.

• document RP-121408 entitled [3 GPP RAN#57 ] sets a new work item for flexible TDD.

• document RP- 121772 entitled [3 GPP RAN#58; December 2012] is a work item to solve the HARQ timeline in flexible TDD when the TDD UL-DL configuration is changed by a different time scale. This document proposes that the HARQ timeline will follow the specific TDD UL-DL configuration that was indicated by the eNB, and that the HARQ timeline still needs to be defined for boundary subframes (such as where granted subframes and their corresponding feedback subframes are in different TDD configurations as compared with the physical downlink/uplink shared channel PDSCH/PUSCH).

[0007] What is needed in the art is a mapping for HARQ feedback that does not require added control signaling overhead and that is compatible with a dynamically changing UL/DL subframe configuration.

SUMMARY:

[0008] In a first exemplary aspect of the invention there is a method operating a wireless radio device. In this aspect the method comprises: a) storing in a local memory of the device hybrid automatic repeat request (HARQ) timing rules for carrier aggregation network deployments in which a primary cell and a secondary cell simultaneously utilize different time division duplex (TDD) uplink-downlink (UL-DL) subframe configurations; b) re-using the HARQ timing rules for flexible TDD UL-DL subframe configuration network deployments in which a same cell changes the TDD UL-DL configuration between a first configuration period and a second configuration period by mapping a data radio resource in the first configuration period to a feedback radio resource in the second configuration period (or mapping a scheduling grant resource in the first configuration period to a data radio resource in the second configuration period) according to the re-used HARQ timing rules; and c) at least one of searching for HARQ feedback or sending HARQ feedback in the mapped feedback radio resource, or searching for data or sending data in the mapped data radio resource. [0009] In a second exemplary aspect of the invention there is an apparatus for operating a wireless radio device. In this aspect the apparatus comprises a processing system, and the processing system comprises at least one processor and a memory storing a set of computer instructions. The at least one memory a) stores hybrid automatic repeat request (HARQ) timing rules for carrier aggregation network deployments in which a primary cell and a secondary cell simultaneously utilize different time division duplex (TDD) uplink-downlink (UL-DL) sub frame configurations. The processing system is configured to cause the apparatus at least to: b) re-use the HARQ timing rules for flexible TDD UL-DL sub frame configuration network deployments in which a same cell changes the TDD UL-DL configuration between a first configuration period and a second configuration period by mapping a data radio resource in the first configuration period to a feedback radio resource in the second configuration period (or mapping a scheduling grant resource in the first configuration period to a data radio resource in the second configuration period) according to the re-used HARQ timing rules; and c) at least one of search for HARQ feedback or send HARQ feedback in the mapped feedback radio resource, or searching for data or sending data in the mapped data radio resource. [0010] In a third exemplary aspect of the invention there is a computer readable memory tangibly storing a set of computer executable instructions for operating a wireless radio device. In this aspect the set of computer executable instructions comprises: a) code for storing in a local memory of the device hybrid automatic repeat request (HARQ) timing rules for carrier aggregation network deployments in which a primary cell and a secondary cell simultaneously utilize different time division duplex (TDD) uplink-downlink (UL-DL) subframe configurations; b) code for re-using the HARQ timing rules for flexible TDD UL-DL subframe configuration network deployments in which a same cell changes the TDD UL-DL configuration between a first configuration period and a second configuration period by mapping a data radio resource in the first configuration period to a feedback radio resource in the second configuration period (or mapping a scheduling grant resource in the first configuration period to a data radio resource in the second configuration period) according to the re-used HARQ timing rules; and c) at least one of cl) code for searching for HARQ feedback in the mapped feedback radio resource and c2) code for sending HARQ feedback in the mapped feedback radio resource, or searching for data or sending data in the mapped data radio resource. [001 1 ] These and other aspects are detailed below with more particularity.

BRIEF DESCRIPTION OF THE DRAWINGS:

[0012] Figure 1 is a timing diagram illustrating a time division duplex (TDD) change of uplink-downlink configurations across two different configuration periods and is an exemplary network deployment in which embodiments of these teachings can be practiced to advantage.

[0013] Figure 2 summarizes in tabular form the prior art agreement in 3 GPP for PDSCH HARQ timing of the Scell for component carrier specific TDD configurations in LTE Release 11.

[0014] Figure 3 summarizes in tabular form the prior art agreement in 3 GPP for PDSCH HARQ timing for case C of Figure 2 of the Scell for component carrier specific TDD configurations in LTE Release 11.

[0015] Figure 4 summarizes in tabular form the prior art agreement for the self-scheduling cases A through D for the Scell PUSCH HARQ timing. [0016] Figure 5 illustrates three of the seven UL-DL sub frame configurations that are conventional in EUTRANs for explaining how the CA HARQ timing rules are re-used according to these teachings for mapping HARQ feedback when the TDD configuration is dynamically flexible. [0017] Figure 6 is a logic flow diagram that illustrates a method for operating a network access node and a user equipment/UE, and a result of execution by an apparatus of a set of computer program instructions embodied on a computer readable memory for operating such an eNB or a UE, in accordance with certain exemplary embodiments of this invention.

[0018] Figure 7 is a simplified block diagram of a UE, and a cellular network represented by an eNB and by a MME, which are exemplary electronic devices suitable for use in practicing the exemplary embodiments of the invention.

DETAILED DESCRIPTION:

[0019] The examples detailed herein are in the context of a network access node/cell/base station and a UE operating with E-UTRA radio access technology and employing flexible TDD UL/DL sub frame configurations. This context provides a practical scenario for describing the inventive concepts herein, and these teachings may be utilized with other types of radio access technologies (RATs) among the network and the UE without departing from the principles set forth herein, whether the changes to the UL/DL sub frame configurations are dynamic, semi-static or only occasional.

[0020] When the TDD UL-DL configuration is changed, the HARQ timeline (mapping) should be also changed according to the changed TDD UL-DL configuration. However, HARQ timing design for subframes at the DL/UL configuration change boundary cannot reuse the legacy HARQ timeline scheme since otherwise there will be feedback or (re)transmission loss. Recalling the example in Figure 1 where the TDD configuration changing period is 10ms and TDD Configuration 1 and TDD configuration 0 are used in the two periods 101, 102 respectively, a PUSCH in sub frame 8 of the first period 101 has to be fed back in one DL subframe in the 2^nd period 102. Conventional E-UTRAN would map feedback corresponding to the PUSCH in subframe #8 to a physical HARQ indictor channel (PHICH) in subframe #4 as shown by the dotted line 110, but for TDD configuration 0 in the second period 102 subframe #4 is UL. The PHICH might reasonably be located in subframe #5 as shown by the solid line 120.

[0021 ] In the LTE system release 11 there are component carriers which can be used for cross carrier scheduling; a physical downlink control channel PDSCH sent on the primary component carrier (also termed the Pcell for primary cell) can schedule UL or DL resources on a secondary component carrier (or Scell for secondary cell). Adopting cross-carrier scheduling gave rise to some difficulties in TDD HARQ, namely should the HARQ feedback be on the Pcell or the Scell and if the Pcell how is HARQ handled when the Pcell and the Scell use different UL/DL configurations. For the solution presented herein for HARQ timing when the UL/DL configuration is flexible it is useful to review how HARQ timing is handled in the cross carrier scheduling scenario.

[0022] Further detail for the summary below, explained with reference to Figures 2-4, of HARQ timing related to carrier aggregation can be seen at documents RP-121569, RANI status report, LTE Carrier Aggregation Enhancements - core part, RAN#58 meeting; RP-121004, RANI status report, LTE Carrier Aggregation Enhancements - core part, RAN#57 meeting; and RP-120502, RANI status report, LTE Carrier Aggregation Enhancements - core part, RAN#56 meeting.

[0023] Figure 2 summarizes in tabular form the agreement in 3GPP for PDSCH HARQ timing of the Scell for component carrier specific TDD configurations in LTE Release 11. SIB1 refers to system information block type 1, and UL/DL configurations 0 through 6 refer to the seven UL/DL subframe configurations that are conventional in LTE. Self scheduling refers to the scheduling grant (PDCCH) and the scheduled resources (PDSCH or PUSCH) being on the same component carrier. It follows then that the UL HARQ feedback (carried on PHICH) will also be on this same component carrier and DL HARQ feedback (carried on PUCCH) will always on Pcell. Cross carrier scheduling means that the scheduling grant is on a different component carrier than the scheduled resources, and the UL HARQ feedback (carried on PHICH) for data on those scheduled resources is on a different component carrier from the scheduled resources but DL HARQ feedback (carried on PUCCH) will always on Pcell.

[0024] All of Figure 2 encompasses only the self scheduling scenario. For the Pcell HARQ timing, the HARQ-ACK timing of the Pcell PDSCH, the scheduling timing of the Pcell PUSCH, and the HARQ timing of Pcell PUSCH should follow the Pcell timing, which is also the same Pcell timing as was used in Releases 8/9/10. For the Scell HARQ timing, the PDSCH HARQ timing follows one of three different types: case A, case B and case C, each represented by a particular intersection of the Pcell and Scell UL/DL configurations as shown. For case A the Scell PDSCH timing follows the Pcell SIBl configuration if the set of DL sub frames indicated by the Scell SIBl configuration is a subset of the DL sub frames indicated by the Pcell SIBl configuration. Case B is the full duplex case and the agreement is that the Scell PDSCH HARQ timing should follow the Scell SIBl HARQ timing. For case C the Scell PDSCH timing follows the timing shown at Figure 3.

[0025] All of Figure 3 encompasses only the cross scheduling scenario. Figure 3 summarizes in tabular form the agreement in 3GPP for PDSCH HARQ timing for case C of Figure 2 of the Scell for component carrier specific TDD configurations in LTE Release 11. When there is cross carrier scheduling this HARQ timing is to follow the Pcell timing for PDSCH, regardless of the number of component carriers that are aggregated.

[0026] For the full duplex (self-scheduling) cases A through D the Scell PDSCH HARQ timing follows the Scell SIBl configuration in Figure 4. For cross carrier scheduling under case A the Scell PDSCH HARQ timing follows the Scell SIBl configuration, if the set of UL sub frames indicated by the scheduled cell SIBl configuration is a subset of the UL sub frames indicated by the scheduling cell SIBl configuration and if the PUSCH round trip time (RTT) of the scheduling cell SIBl configuration is 10ms. For cross carrier scheduling under cases B through D of Figure 4 the Scell PDSCH HARQ timing follows the scheduled cell timing for PUSCH except configuration combinations {6, 2}, {6, 5}, {0, 2}, {0, 4}, {0, 5}, which UL scheduling/HARQ timing should follow TDD configuration 1.

[0027] According to these teachings there is a set of rules which result in the HARQ related agreement for component carrier specific TDD configurations being also used for the flexible TDD HARQ scenario. [0028] A first such rule is that UL/DL sub frames in the same TDD UL-DL configuration period (each period beginning at a change in the TDD UL-DL configuration such as between periods 101 and 102 of Figure 1) can follow different reference TDD UL-DL configuration for HARQ timeline. There are only two possibilities which are distinguished from among a first and a second type of subframes. The first type of subframes are those UL/DL subframes whose UL feedback/UL grant/DL feedback timing falls to the same TDD UL/DL configuration period of PDSCH/PUSCH subframe according to HA Q timing of the ongoing TDD UL/DL configuration. For subframes of this first type, the reference configuration is to be the ongoing TDD UL/DL configuration. In this case the ongoing TDD UL-DL configuration means the TDD UL-DL configuration that is indicated by eNB and configured for the flexible TDD capable UEs. In the same TDD UL-DL configuration period, the TDD UL-DL configuration is expected to remain the same and this applies for both types of subframes.

[0029] The other possibility concerns the second type of subframes which are opposite the first type. The second type of subframes are those UL/DL subframes whose UL feedback/UL grant/DL feedback timing falls to the different TDD UL/DL configuration period of PDSCH/PUSCH subframe according to HARQ timing of the ongoing TDD UL/DL configuration. For subframes of this second type, the reference configuration is determined by the following rules.

For PDSCH HARQ timing for subframes of the second type (that is, UL feedback timing on a physical uplink control channel PUCCH), re-use the DL reference configuration table that has already been agreed for the self scheduling case of inter-band TDD carrier aggregation with different UL/DL configuration. · For PUSCH HARQ timing for subframes of the second type (that is, UL scheduling timing or the UL grant and DL feedback timing on the PHICH), re-use the UL reference configuration table that has already been agreed for the cross-carrier scheduling case of inter-band TDD carrier aggregation with different UL/DL configurations.

[0030] There is according to these teachings a further rule for subframes of the second type when re-using the UL/DL reference configuration table that has been agreed for inter-band TDD carrier aggregation with different UL/DL configurations. • When re-using DL reference configuration to deduce the HARQ timing for PDSCH in subframes of the second type, the TDD configuration containing the PDSCH transmission can be regarded as the configuration on the Scell, and the TDD configuration containing the UL feedback (PUCCH) corresponding to the PDSCH transmission can be regarded as the configuration on the Pcell.

• When re-using UL reference configuration to deduce the HARQ timing for PUSCH in subframes of the second type, the TDD configuration containing the PUSCH transmission can be regarded as the configuration of the scheduled cell, and the TDD configuration containing the UL grant or DL feedback (PHICH) transmission can be regarded as the configuration of the scheduling cell.

[0031 ] The following examples explain how the above rules to re-use the existing agreements for HARQ with component carriers for flexible TDD UL-DL subframe configuration may be implemented. These examples assume the seven UL-DL subframe configurations that are conventional in EUTRANs, three of which are illustrated at Figure 5.

[0032] To re-use the existing component carrier self scheduling or cross-carrier scheduling HARQ agreements for flexible TDD UL-DL subframe configuration, those existing agreements are followed for downlink, since the downlink resources (PDSCH assigned by the PDCCH is transmitted on the same configuration but the corresponding HARQ (on the PUCCH) is transmitted in another configuration period, so re-using the agreement for self-scheduling is fully effective. For the case of uplink resources (PUSCH) being scheduled, since the UL grant is transmitted on another configuration, the existing agreement for cross-carrier scheduling is re-used for the flexible TDD UL-DL subframe configuration scenario. For the HARQ feedback of the scheduled uplink resources, since the feedback (on the PHICH) will be transmitted in another configuration, the existing agreement for cross-carrier scheduling is also re-used for the flexible TDD UL-DL subframe configuration scenario. [0033] Applying these specifically to the UL-DL subframe configurations shown at Figure 5, first assume there are downlink resources granted in configuration 1. In this case configuration 1 can be seen as the Pcell in the existing HA Q agreements for component carrier scenarios, since the PUCCH will be transmitted in configuration 1. Then according to the agreement for component carrier specific TDD, those downlink subframes whose PUCCH is transmitted in frame n+1 will follow the Pcell timing, which is the timing for configuration 1 in this example. The same holds true when there is a flexible TDD configuration change from configuration 1 to configuration 2, both of which are shown at Figure 5.

[0034] Now consider an example in which an uplink resource is granted and the flexible TDD configuration is changed from configuration 0 to configuration 1 , both of which are also shown at Figure 5. In this example the uplink subframe in configuration 1 whose uplink grant in configuration 0 should follow the cross-carrier scheduling HARQ agreement with regards to configuration 0 is the scheduling cell. So according to the existing component carrier HARQ agreement, the uplink scheduling timing for UL subframes in configuration 1 whose uplink grant is in configuration 0 should follow the timing of the scheduled cell, which in this example would be configuration 1.

[0035] Continuing with this same uplink granted resource example, the timing for the downlink HARQ feedback (the PHICH) corresponding to that granted uplink resource when the flexible TDD configuration is changed from configuration 0 to configuration 1, the uplink subframe in configuration 0 whose PHICH in configuration 1 should follow the existing HARQ agreement for cross-carrier scheduling with regards to configuration 1 is the scheduling cell. Then according to that existing agreement, the PHICH timing for the uplink subframes in configuration 0 having their corresponding PHICH in configuration 1 should follow the timing of the scheduled cell, which in this example is configuration 0.

[0036] The above solutions for flexible TDD UL-DL configuration and corresponding HARQ provides the technical effect of avoiding re-design of HARQ timing for the flexible TDD scenario by re-using the existing agreement for HARQ concerning component carrier scenarios. Since those existing agreements were the result of extensive vetting for crossover effects to other parts of the LTE system, adapting them for the flexible TDD scenario should be straightforward and less involved than vetting and adopting a wholly new design for flexible TDD HARQ.

[0037] Figure 6 presents a summary of the above teachings operating a wireless radio device such as for example a network access node (eNB or NodeB or base station) or a user equipment (UE). At block 602 there is stored in a local memory of the device hybrid automatic repeat request (HARQ) timing rules for carrier aggregation network deployments in which a primary cell and a secondary cell simultaneously utilize different time division duplex (TDD) uplink-downlink (UL-DL) subframe configurations. Block 604 re-uses those HARQ timing rules, specifically the HARQ timing rules are re-used for flexible TDD UL-DL subframe configuration network deployments in which a same cell changes the TDD UL-DL configuration between a first configuration period and a second configuration period, and these rules are re-used to map a data radio resource in the first configuration period to a feedback radio resource in the second configuration period according to the re-used HARQ timing rules. In another embodiment these same rules are re-used to map a scheduling grant resource in the first configuration period to a data radio resource in the second configuration period according to the re-used HARQ timing rules. In the examples above the rules are used for both mapping situations.

[0038] Figure 1 illustrates different configurations in the different first 101 and second 102 configuration periods. Referring to Figure 5, assume for example the first configuration period used configuration 0 and the second configuration period used configuration 1. Then for example data in a downlink radio resource PDSCH in subframe 6 of configuration 0 in the first configuration period would map to an uplink radio resource PUCCH in subframe 2 of configuration 1 in the second configuration period.

[0039] With that mapping now complete in Figure 6 for the flexible TDD UL-DL subframe configuration that changed across the first and second configuration periods, block 606 tells that there is a search for the HARQ feedback in the mapped feedback radio resource or the HA Q feedback is sent in the mapped feedback radio resource. Whether the feedback radio resource is used for the sending or for searching depends on whether Figure 6 is considered from the perspective of the network or the user equipment, and of course also whether the feedback resource is uplink or downlink. For the case in which the mapping of block 604 is from the scheduling grant resource in the first configuration to the data radio resource in the second configuration, then the searching for or sending of block 606 refers to searching for data or sending data in the data radio resource that maps from the scheduling radio resource. As with the HARQ feedback, with the mapped data radio resource it depends on what perspective is being considered. Since scheduling grants are only from the network (and thus downlink) the mapped data radio resource in this case must be uplink. The network access node searches for the UE's data on that uplink data radio resource that maps from the scheduling radio resource, and the UE sends to the network its uplink data on that same mapped uplink data radio resource.

[0040] Some of the non-limiting implementations detailed above are also summarized at Figure 6 following block 606. Block 608 details one non-limiting embodiment from above in which the HARQ timing rules that are for self-scheduling are re-used when the data radio resource (and/or the scheduling grant resource) in the first configuration period is downlink, and the mapped feedback radio resource (and/or the mapped data radio resource) in the second configuration period is uplink; and where the HARQ timing rules that are for cross-carrier scheduling are re-used when the data radio resource in the first configuration period is uplink and the feedback radio resource in the second configuration period is downlink.

[0041 ] In another non-limiting embodiment that was detailed above and which may be combined with the embodiments of block 608, for the case in which the data radio resource and/or the scheduling grant resource is downlink, and the feedback radio resource and/or the mapped uplink data radio resource is uplink, the HARQ timing rules are re-used by:

• regarding a TDD UL-DL subframe configuration which carries the downlink data radio resource and/or the scheduling grant resource as a TDD UL-DL subframe configuration of the secondary cell; and • regarding a TDD UL-DL subframe configuration which carries the mapped uplink feedback radio resource and/or the mapped uplink data radio resource as a TDD UL-DL subframe configuration of the primary cell. [0042] In a still further non-limiting embodiment that was detailed above and which may also be combined with the embodiments of block 608, for the case in which the data radio resource and/or the scheduling grant resource is uplink and the feedback radio resource is downlink, the HA Q timing rules are re-used by:

• regarding a TDD UL-DL subframe configuration which carries the uplink data radio resource as a TDD UL-DL subframe configuration of whichever of the primary and secondary cell is a scheduled cell under the HARQ timing rules; and

• regarding a TDD UL-DL subframe configuration which carries the downlink feedback radio resource as a TDD UL-DL subframe configuration of whichever of the primary and secondary cell is a scheduling cell under the HARQ timing rules.

[0043] The process in Figure 6 can represent a method or a manner of operating an E-UTRAN access node that searches for uplink HARQ feedback and that sends downlink HARQ feedback in the mapped feedback radio resources, and/or that searches for data in the mapped data radio resource. Alternatively Figure 6 can represent a method or a manner of operating a user equipment that searches for downlink HARQ feedback and that sends uplink HARQ feedback in the mapped feedback radio resources, and/or that sends data in the mapped data radio resource.

[0044] The logic diagram of Figure 6 may be considered to illustrate the operation of a method, and a result of execution of a computer program stored in a computer readable memory, and a specific manner in which components of an electronic device/wireless radio device are configured to cause that device to operate, whether such a device is the network access node (eNB or Node B or base station) or the UE (mobile terminal or handset or mobile station) or some other portable electronic device that is connected to the cellular network, or one or more components thereof such as a modem, chipset, or the like. The various blocks shown in Figure 6 may also be considered as a plurality of coupled logic circuit elements constructed to carry out the associated function(s), or specific result of strings of computer program code or instructions stored in a memory.

[0045] Such blocks and the functions they represent are non-limiting examples, and may be practiced in various components such as integrated circuit chips and modules, and that the exemplary embodiments of this invention may be realized in an apparatus that is embodied as an integrated circuit. The integrated circuit, or circuits, may comprise circuitry (as well as possibly firmware) for embodying at least one or more of a data processor or data processors, a digital signal processor or processors, baseband circuitry and radio frequency circuitry that are configurable so as to operate in accordance with the exemplary embodiments of this invention.

[0046] Such circuit/circuitry embodiments include any of the following: (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and (b) combinations of circuits and software (and/or firmware), such as: (i) a combination of processor(s) or (ii) portions of processor(s)/software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a network access node or a user equipment/UE, to perform the various functions summarized at Figure 6 and (c) 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" also covers, for example, a baseband integrated circuit or applications processor integrated circuit for a user equipment UE or for a network access node/eNB or a similar integrated circuit in a server or other network device which operates according to these teachings.

[0047] Reference is now made to Figure 7 for illustrating a simplified block diagram of various electronic devices and apparatus that are suitable for use in practicing the exemplary embodiments of this invention. In Figure 7 a radio network access node that is illustrated as an eNB 22 is adapted for communication over a wireless link 21 with an apparatus, such as a mobile terminal or UE 20. The access node 22 may be any access node such as a node B or an eNB (including frequency selective repeaters and remote radio heads) of any wireless network, such as UTRAN, WCDMA, GSM, GERAN, E-UTRAN/LTE, LTE-Advanced and the like. The operator network of which the access node 22 is a part may also include a network control element such as a radio network controller RNC in the case of a UTRAN and WCDMA network. For the case of LTE/LTE-Advanced networks, the higher network entity represents a mobility management entity MME as shown in Figure 7, which may also serve as the serving gateway S-GW. This higher network entity 26 generally provides connectivity with the core cellular network and with further networks (e.g., a publicly switched telephone network PSTN and/or a data communications network/Internet).

[0048] The UE 20 includes processing means such as at least one data processor (DP) 20A, storing means such as at least one computer-readable memory (MEM) 20B storing at least one computer program (PROG) 20C, communication means such as a transmitter TX 20D and a receiver RX 20E for bidirectional wireless communications with the access node 22 using the operative radio access technology. All of the relevant wireless communications are via one or more antennas 20F. Also stored in the MEM 20B at reference number 20G are the computer code or algorithms for the already agreed HARQ timing rules for carrier aggregation (CA) deployments, and the code or algorithms for re-using those HARQ timing rules for flexible TDD UL-DL subframe configuration deployments, according to non-limiting example embodiments above. [0049] The access node 22 also includes processing means such as at least one data processor (DP) 22A, storing means such as at least one computer-readable memory (MEM) 22B storing at least one computer program (PROG) 22C, and communication means such as a transmitter TX 22D and a receiver RX 22E for bidirectional wireless communications with the UE 20 via one or more antennas 22F. The access node 22 stores at block 22G in certain embodiments its own computer software code or algorithms for the already agreed CA HARQ timing rules, and the code or algorithms for re-using those HARQ timing rules for flexible TDD UL-DL subframe configuration deployments. In some radio technologies the access node 22 will have a direct data/control link 23 with other adjacent access nodes.

[0050] Also at Figure 6 is shown a higher network entity 26 above the radio access node 22. In LTE/LTE -Advanced this may be a mobility management entity or a serving gateway as noted above; in UTRAN and WCDMA it is a radio network controller R C. However implemented, the higher network entity 26 includes processing means such as at least one data processor (DP) 26A, storing means such as at least one computer-readable memory (MEM) 26B storing at least one computer program (PROG) 26C, and communication means such as a modem 26F for bidirectional communications with the access node 22 and with other access nodes under its control or coordination over the data and control link 25.

[0051 ] While not particularly illustrated for the UE 20 or the access node 22, those devices are also assumed to include as part of their wireless communicating means a modem and/or a chipset and/or an antenna chip which may or may not be inbuilt onto a radiofrequency (RF) front end module within those devices 20, 22 and which also operates according to the teachings set forth above.

[0052] At least one of the PROGs 20C in the UE 20 is assumed to include a set of program instructions that, when executed by the associated DP 20A, enable the device to operate in accordance with the exemplary embodiments of this invention, as detailed above and particularly summarized at Figure 6. The access node 22 also has software stored in its MEM 22B to implement similar aspects of these teachings as has been described, depending on whether the HARQ feedback is being sent uplink or downlink but the mapping is similar. In these regards the exemplary embodiments of this invention may be implemented at least in part by computer software stored on the MEM 20B, 22B which is executable by the DP 20A of the UE 20 and/or by the DP 22A of the access node 22; or by hardware, or by a combination of tangibly stored software and hardware (and tangibly stored firmware) in any one or more of these devices 20, 22. In this manner the respective DP with the MEM and stored PROG may be considered a data processing system. Electronic devices implementing these aspects of the invention need not be the entire devices as depicted at Figure 7 or may be one or more components of same such as the above described tangibly stored software, hardware, firmware and DP, or a system on a chip SOC or an application specific integrated circuit ASIC or a digital signal processor DSP or a modem or an antenna module or a RF front end module as noted above. [0053] In general, the various embodiments of the UE 20 can include, but are not limited to personal portable digital devices having wireless communication capabilities, including but not limited to cellular and other mobile phones, radio handsets, wearable radio-telephony devices, navigation devices, laptop/palmtop/tablet computers, digital cameras and music devices, Internet appliances, USB dongles and data cards.

[0054] Various embodiments of the computer readable MEMs 20B, 22B, 26B include any data storage technology type which is suitable to the local technical environment, including but not limited to semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, removable memory, disc memory, flash memory, DRAM, SRAM, EEPROM and the like. Various embodiments of the DPs 20A, 22A, 26A include but are not limited to general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and multi-core processors. [0055] Various modifications and adaptations to the foregoing exemplary embodiments of this invention may become apparent to those skilled in the relevant arts in view of the foregoing description. While the exemplary embodiments have been described above in the context of the EUTRAN/LTE system, as noted above the exemplary embodiments of this invention are not limited for use with only this particular type of wireless radio access technology networks.

Further, some of the various features of the above non-limiting embodiments may be used to advantage without the corresponding use of other described features. The foregoing description should therefore be considered as merely illustrative of the principles, teachings and exemplary embodiments of this invention, and not in limitation thereof.

Claims

WHAT IS CLAIMED IS:

1. A method for operating a wireless radio device, comprising:

storing in a local memory of the device hybrid automatic repeat request (HA Q) timing rules for carrier aggregation network deployments in which a primary cell and a secondary cell simultaneously utilize different time division duplex (TDD) uplink-downlink (UL-DL) subframe configurations;

re-using the HARQ timing rules for flexible TDD UL-DL subframe configuration network deployments in which a same cell changes the TDD UL-DL configuration between a first configuration period and a second configuration period by mapping a data radio resource in the first configuration period to a feedback radio resource in the second configuration period and/or mapping a scheduling grant resource in the first configuration period to a data radio resource in the second configuration period according to the re-used HARQ timing rules; and

at least one of searching for HARQ feedback or sending HARQ feedback in the mapped feedback radio resource, or searching for data or sending data in the mapped data radio resource.

2. The method according to claim 1, wherein the HARQ timing rules are for self-scheduling and are re-used when the data radio resource and/or the scheduling grant resource in the first configuration period is downlink, and the mapped feedback radio resource and/or the mapped data radio resource in the second configuration period is uplink.

3. The method according to claim 2, wherein the HARQ timing rules are for cross-carrier scheduling and are re-used when the data radio resource in the first configuration period is uplink and the feedback radio resource in the second configuration period is downlink.

4. The method according to any of claims 1-3 wherein, only for the case in which the data radio resource and/or the scheduling grant resource is downlink and the mapped feedback radio resource and/or the mapped data radio resource is uplink, the HARQ timing rules are re-used by: regarding a TDD UL-DL subframe configuration which carries the downlink data radio resource and/or the downlink scheduling grant resource as a TDD UL-DL subframe configuration of the secondary cell; and

regarding a TDD UL-DL subframe configuration which carries the mapped uplink feedback radio resource and/or the mapped uplink data radio resource as a TDD UL-DL subframe configuration of the primary cell.

5. The method according to claim 4 wherein, only for the case in which the data radio resource is uplink and the feedback radio resource is downlink, the HA Q timing rules are re-used by:

regarding a TDD UL-DL subframe configuration which carries the uplink data radio resource as a TDD UL-DL subframe configuration of whichever of the primary and secondary cell is a scheduled cell under the HARQ timing rules; and

regarding a TDD UL-DL subframe configuration which carries the downlink feedback radio resource as a TDD UL-DL subframe configuration of whichever of the primary and secondary cell is a scheduling cell under the HARQ timing rules.

6. The method according to any of claims 1-5, wherein the method is executed by the wireless radio device which is a network access node that searches for uplink HARQ feedback and that sends downlink HARQ feedback in the mapped feedback radio resources, and/or that searches for data in the mapped data radio resource.

7. The method according to any of claims 1-5, wherein the method is executed by the wireless radio device which is a user equipment that searches for downlink HARQ feedback and that sends uplink HARQ feedback in the mapped feedback radio resources, and/or that sends data in the mapped data radio resource.

8. An apparatus for operating a wireless radio device, the apparatus comprising a processing system, and the processing system comprising at least one processor and at least one memory including computer program code;

wherein the at least one memory stores hybrid automatic repeat request (HARQ) timing rules for carrier aggregation network deployments in which a primary cell and a secondary cell simultaneously utilize different time division duplex (TDD) uplink-downlink (UL-DL) subframe configurations;

and wherein the processing system is configured to cause the apparatus at least to: re-use the HA Q timing rules for flexible TDD UL-DL subframe configuration network deployments in which a same cell changes the TDD UL-DL configuration between a first configuration period and a second configuration period by mapping a data radio resource in the first configuration period to a feedback radio resource in the second configuration period or by mapping a scheduling grant resource in the first configuration period to a data radio resource in the second configuration period according to the re-used HARQ timing rules; and

at least one of search for HARQ feedback or send HARQ feedback in the mapped feedback radio resource, or search for data or send data in the mapped data radio resource.

9. The apparatus according to claim 8, wherein the HARQ timing rules are for self-scheduling and are re-used when the data radio resource and/or the scheduling grant resource in the first configuration period is downlink, and the mapped feedback radio resource and/or the mapped data radio resource in the second configuration period is uplink.

10. The apparatus according to claim 9, wherein the HARQ timing rules are for cross-carrier scheduling and are re-used when the data radio resource in the first configuration period is uplink and the feedback radio resource in the second configuration period is downlink.

11. The apparatus according to any of claims 8-10 wherein, only for the case in which the data radio resource and/or the scheduling grant resource is downlink, and the mapped feedback radio resource and/or the mapped data radio resource is uplink, the HARQ timing rules are re-used by:

regarding a TDD UL-DL subframe configuration which carries the downlink data radio resource and/or the downlink scheduling grant resource as a TDD UL-DL subframe configuration of the secondary cell; and

12. The apparatus according to claim 11 wherein, only for the case in which the data radio resource is uplink and the feedback radio resource is downlink, the HARQ timing rules are re-used by:

13. The apparatus according to any of claims 8-12, wherein the wireless radio device is a network access node that searches for uplink HARQ feedback and that sends downlink HARQ feedback in the mapped feedback radio resources, and/or that searches for data in the mapped data radio resource.

14. The apparatus according to any of claims 8-12, wherein the wireless radio device is a user equipment that searches for downlink HARQ feedback and that sends uplink HARQ feedback in the mapped feedback radio resources, and/or that sends data in the mapped data radio resource.

15. A computer readable memory tangibly storing a set of computer instructions for operating a wireless radio device, the set of computer instructions comprising:

code for storing in a local memory of the device hybrid automatic repeat request

(HARQ) timing rules for carrier aggregation network deployments in which a primary cell and a secondary cell simultaneously utilize different time division duplex (TDD) uplink-downlink (UL-DL) subframe configurations;

code for re-using the HARQ timing rules for flexible TDD UL-DL subframe configuration network deployments in which a same cell changes the TDD UL-DL configuration between a first configuration period and a second configuration period by mapping a data radio resource in the first configuration period to a feedback radio resource in the second configuration period or mapping a scheduling grant resource in the first configuration period to a data radio resource in the second configuration period according to the re-used HA Q timing rules; and

at least one of code for searching for HARQ feedback in the mapped feedback radio resource and code for sending HARQ feedback in the mapped feedback radio resource, or searching for data or sending data in the mapped data radio resource.

16. The computer readable memory according to claim 15, wherein the HARQ timing rules are for self-scheduling and are re-used when the data radio resource and/or the scheduling grant resource in the first configuration period is downlink, and the mapped feedback radio resource and/or the mapped data radio resource in the second configuration period is uplink.

17. The computer readable memory according to claim 16, wherein the HARQ timing rules are for cross-carrier scheduling and are re-used when the data radio resource in the first configuration period is uplink and the feedback radio resource in the second configuration period is downlink.

18. The computer readable memory according to any of claims 15-17 wherein, only for the case in which the data radio resource and/or the scheduling grant resource is downlink, and the feedback radio resource and/or the mapped uplink data radio resource is uplink, the HARQ timing rules are re-used by:

regarding a TDD UL-DL subframe configuration which carries the downlink data radio resource and/or the scheduling grant resource as a TDD UL-DL subframe configuration of the secondary cell; and

regarding a TDD UL-DL subframe configuration which carries the mapped uplink feedback radio resource and/or the mapped uplink data radio resource as a TDD

UL-DL subframe configuration of the primary cell.

19. The computer readable memory according to claim 18 wherein, only for the case in which the data radio resource is uplink and the feedback radio resource is downlink, the HARQ timing rules are re-used by:

20. The computer readable memory according to any of claims 15-19, wherein the wireless radio device is a network access node that searches for uplink HARQ feedback and that sends downlink HARQ feedback in the mapped feedback radio resources, and/or that searches for data in the mapped data radio resource.

21. The computer readable memory according to any of claims 15-19, wherein the wireless radio device is a user equipment that searches for downlink HARQ feedback and that sends uplink HARQ feedback in the mapped feedback radio resources, and/or that sends data in the mapped data radio resource.