HK1221081B - Dynamical time division duplex uplink and downlink configuration in a communications network - Google Patents

Description

Dynamic time division duplex uplink and downlink configuration in communication networks

Related applications

This application claims the benefit of priority to, and incorporates by reference into, U.S. Provisional Patent Application No. 61/859,121 (Attorney Docket No. P59845Z), filed July 26, 2013. This application also claims the benefit of priority to, and incorporates by reference into, U.S. Non-Provisional Patent Application No. 14/247,675 (Attorney Docket No. P63597), filed April 8, 2014.

Background Art

In wireless communication systems, downlink and uplink transmissions can be organized into two duplex modes: frequency division duplex (FDD) and time division duplex (TDD). FDD uses paired spectrum, where gaps in the frequency domain are used to separate uplink (UL) and downlink (DL) transmissions. In TDD systems, unpaired spectrum can be used, where both UL and DL are transmitted on the same carrier frequency. In the time domain, UL and DL are separated into non-overlapping time slots.

The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) TDD heterogeneous system operates synchronously to avoid UL/DL inter-cell interference between base stations or nodes (e.g., enhanced Node B (eNode B)) and/or mobile terminals (e.g., user equipment (UE)). The geographical area served by an eNode B is generally referred to as a cell. The cells in the network generally use the same UL/DL configuration for synchronous operation of the LTE-TDD heterogeneous system. The UL/DL configuration includes the frame configuration and the UL/DL resource allocation in one radio frame. In addition, the network can use the UL/DL configuration to align the frame transmission boundaries in time. Synchronous operation may be effective for mitigating interference. However, synchronous operation cannot be optimized for traffic adaptation and significantly reduces the packet throughput of small cells in heterogeneous networks (HetNets).

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the present disclosure will become apparent from the following detailed description taken in conjunction with the accompanying drawings which together illustrate features of the present disclosure by way of example, in which:

FIG1 depicts a multi-radio access technology (RAT) heterogeneous network (HetNet) with multiple layers of lower power nodes overlaid on a macro cell, according to an example;

FIG2 a shows uplink/downlink (UL/DL) subframes spaced apart in the frequency domain for a frequency division duplex (FDD) mode according to an example;

FIG2 b shows UL/DL subframes sharing a carrier frequency in a time division duplex (TDD) mode according to an example;

3A depicts a downlink control information (DCI) format for a single component carrier (CC) supporting dynamic UL/DL reconfiguration according to an example;

FIG3B depicts a DCI format for multiple CCs supporting dynamic UL/DL reconfiguration according to an example;

FIG4 depicts DCI format X that may be used to indicate a TDD UL/DL configuration according to an example;

FIG5 depicts a DCI format for UL/DL configuration indication according to an example;

FIG6 shows a table depicting encoding of a 3-bit target cell identity (TCI) codeword for TDD UL/DL configuration indication according to an example;

FIG7 shows a table depicting encoding of a 2-bit TCI codeword for TDD UL/DL configuration indication according to an example;

FIG8 shows a signaling flow between a user equipment (UE) and EUTRAN to establish a dynamic UL/DL configuration according to an example;

FIG9 illustrates a signaling flow between a UE and an Evolved Universal Terrestrial Radio Access Network (EUTRAN) for establishing dynamic UL/DL configuration according to an example;

FIG10 illustrates a physical downlink control channel (PDCCH) that may be used for DCI format X transmission according to an example;

FIG11 illustrates a common search space (CSS) on a PDCCH that may be used for DCI format X transmission according to an example;

FIG12 shows a DCI format X including a UL/DL configuration indication field according to an example;

FIG13 shows a DCI format X including a UL/DL configuration indication field according to an example;

FIG14 shows a subset of aggregation levels on a primary cell (PCell) according to an example;

FIG15 illustrates an enhanced physical downlink control channel (EPDCCH) physical resource block (PRB) group configured to be shared by all UEs configured with EPDCCH monitoring functionality according to an example;

FIG16 shows a TDD UL/DL configuration supporting coordinated multi-point (CoMP) scenario 4 according to an example;

FIG17 shows a table with configurations for a TDD UL/DL reconfiguration indication according to an example;

FIG18 shows UL/DL configuration in CoMP scenario 3 according to an example;

FIG19 shows a table showing configurations for a TDD UL/DL reconfiguration indication according to an example;

FIG20 depicts functionality of computer circuitry of a UE operable to dynamically change UL/DL configuration in a communication network according to an example;

FIG21 depicts functionality of another computer circuit of an enhanced Node B (eNode B) operable to dynamically change UL/DL configuration in a communication network according to an example;

FIG22 illustrates a method for dynamically changing UL/DL configuration in a communication network according to an example; and

FIG23 shows a schematic diagram of a UE according to an example.

Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It will be understood that no limitation of the scope of the invention is intended herein.

DETAILED DESCRIPTION

Before disclosing and describing the present invention, it will be understood that the present invention is not limited to the specific structures, processing steps, or materials disclosed herein, but can be extended to equivalents that can be recognized by those skilled in the relevant art. It should also be understood that the terms used herein are only used for the purpose of describing specific examples and are not intended to be limiting. The same reference numerals in different figures represent the same elements. The numbers provided in the flow charts and processes are provided to clearly illustrate the steps and operations and do not necessarily indicate a specific order or sequence.

Mobile devices are increasingly being equipped with multiple radio access technologies (multi-RAT) that can connect to and select among different types of radio technologies, including cellular technologies that use the licensed portion of the radio spectrum, and wireless local area network (WLAN) and personal area network (PAN) technologies that typically use the unlicensed portion of the radio spectrum.

In a homogeneous network, a base station or macro node can provide basic wireless coverage to mobile devices within the node's coverage area (i.e., a cell). Heterogeneous networks (HetNets) were introduced to handle the increasing traffic load on macro nodes caused by the increasing use and functionality of mobile devices.

A HetNet can include multiple types of radio access nodes and/or radio access technologies in a wireless network. A HetNet can include macro nodes (e.g., enhanced Node Bs (eNBs) or base stations (BSs)) covered by multiple layers of small nodes or cells (e.g., micro nodes, pico nodes, femto nodes, home nodes, relay stations, WiFi access points (APs), etc.). Small nodes (also known as low-power nodes) can be deployed unevenly or uncoordinated within the coverage area (i.e., cells) of the macro nodes. Macro nodes can be used for basic coverage, and small nodes can be used to fill coverage holes to increase capacity at the boundaries between macro node coverage areas or in hot spots, thereby improving indoor coverage where building structures hinder signal transmission. Figure 1 depicts a multi-RAT HetNet in a macro cell 110, where multiple layers of lower-power nodes or small nodes (including micro nodes 130, pico nodes 140, femto nodes 150, and WiFi APs 160 or other types of WLAN nodes or PAN nodes) are overlaid on a macro node 120.

The high demand of UEs for increasing throughput can be met by deploying clusters of small nodes to provide acceptable quality of service (QoE) to the UEs. In one embodiment, dense clustering of small nodes can be used in hot spots to provide closer service nodes to more UEs, thereby increasing network capacity. As the number of small nodes deployed in a given area increases, the interference between small nodes increases. When the interference between small nodes reaches a threshold value, there is an upper limit on the number of small nodes that can be deployed in the hot spot area.

Traditionally, a disadvantage of high-density deployment or clustering of small nodes is the level of interference between small nodes (e.g., the level of interference between multiple small nodes in a dense area). Inter-small node interference reduces the signal-to-interference-plus-noise ratio (SINR) and/or signal-to-noise ratio (SNR) between the UE and the small nodes, resulting in a decrease or degradation of UE throughput.

In wireless communication systems (e.g., 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) systems), downlink (DL) transmissions and uplink (UL) transmissions can be organized into two duplex modes: frequency division duplex (FDD) mode and time division duplex (TDD) mode. The FDD mode can use paired spectrum, wherein gaps in the frequency domain are used to separate uplink (UL) transmissions from downlink (DL) transmissions. FIG2A shows UL and DL subframes separated in the frequency domain for the FDD mode. In a TDD system, an unpaired spectrum can be used, wherein UL and DL are sent on the same carrier frequency. UL transmissions and DL transmissions are separated in non-overlapping time slots in the time domain. FIG2B shows that in the TDD mode, UL subframes and DL subframes share a carrier frequency. As used herein, the term UL/DL is intended to refer to uplink and downlink.

A wireless communication system may operate synchronously to avoid UL/DL inter-cell interference between base stations (e.g., eNode Bs) and/or mobile terminals (e.g., UEs). Cells in the wireless communication system may use the same UL/DL configuration for synchronous operation in the wireless communication system. The UL/DL configuration may include a frame configuration and UL/DL resource allocation.

Using the same frame configuration in HetNet deployment scenarios will reduce the quality of service (QoS) for UEs in the communication network. Data traffic in HetNet scenarios may vary over time domains or small areas. For example, a selected group of cells may have dominant traffic in the DL transmission direction or the UL transmission direction that changes over time. The dominant traffic transmission direction can use more spectrum resources than the non-dominant traffic transmission direction to improve system throughput performance and QoS for low or medium traffic loads. In HetNet deployment scenarios, since small cells are closer to end users and the isolation level between eNode Bs is higher, most eNode Bs can be regarded as isolated cells. Isolated cells are cells that have small nodes that create a relatively low level of inter-cell interference with other small cells in the macro cell.

In one embodiment, each small node in the isolated cell can dynamically configure or reconfigure the UL/DL configuration of the small node to adapt to the instantaneous data traffic conditions or the constantly changing real-time data traffic conditions in the serving cell. In another embodiment, each small node in the isolated cell can dynamically configure or reconfigure the UL/DL configuration of the small node by using a cyclic redundancy check (CRC) check bit, which is assigned to the TDD-Config-RNTI scrambling for eIMTA operation. In one embodiment, signaling options such as system information block (SIB), paging, radio resource control (RRC), medium access control (MAC) signaling, and/or L1 signaling can be used to support UL/DL reconfiguration in different traffic adaptation time scales. For example, L1 signaling can be used for UL/DL reconfiguration as a robust signaling option with lower control overhead and shorter delay.

In one embodiment, blind decoding may be used for a selected signaling option such as L1 signaling. In another embodiment, a DCI format such as a physical downlink control channel (PDCCH) may be used to send carrier-independent UL/DL configuration information for each serving cell. Figures 3A and 3B illustrate DCI formats for indicating carrier-independent UL/DL configurations. The DCI formats such as the PDCCH in Figures 3A and 3B include a TDD UL/DL configuration indicator field (CIF) for the selected UL/DL configuration. Figure 3A depicts a DCI format (e.g., PDCCH) for a single component carrier (CC) supporting dynamic UL/DL reconfiguration. Figure 3B depicts a DCI format (e.g., PDCCH) for multiple CCs supporting dynamic UL/DL reconfiguration. In one embodiment, the DCI format may be used in a CoMP4 scenario to enable independent UL/DL configuration for each transmission point (TP).

In one embodiment, the network may be configured to customize DCI signals for traffic adaptation in a TDD system. In one embodiment, a unified DCI format for carrying UL/DL configuration information may be dynamically updated and sent at selected time intervals. For example, the DCI format may be dynamically updated every 10 milliseconds. In another embodiment, the DCI format may enable independent UL/DL configuration for each serving cell for a selected deployment scenario. The selected deployment scenarios may include: a single carrier scenario; a coordinated multi-point (CoMP) scenario (e.g., CoMP scenario 3 or CoMP scenario 4); a carrier aggregation (CA) scenario; and a CoMP scenario where CA is enabled on a remote radio head (RRH) (e.g., a combined CA and CoMP scenario).

Figure 4 shows a new DCI format X (e.g., PDCCH) that can be used to indicate a TDD UL/DL configuration, wherein the DCI format X has an M-bit TDD UL/DL configuration indicator field (CIF) for indicating the UL/DL configuration. In one embodiment, M can specify a number or a literal. X in DCI format X can specify a number or a literal. DCI format X can simultaneously carry the TDD UL/DL configurations of multiple serving cells. In one embodiment, the DCI format can be sent on all fixed DL subframes (e.g., subframe 0, subframe 1, subframe 5, subframe 6). In another embodiment, the DCI format can be sent on a subset of fixed subframes. In another embodiment, the DCI format can be sent on all DL subframes (including fixed DL subframes and flexible subframes). The advantage of sending the DCI format on all DL subframes is that it enables a discontinuous reception (DRX) UE to obtain the actual UL/DL configuration being used by the eNode B when the DRX UE wakes up in a flexible subframe.

In one embodiment, DCI format X may include a set of TDD UL/DL configuration indicator (TCI) fields 1, 2, ..., N, where N is signaled by the eNode B in RRC signaling for each eIMTA-enabled UE. In another embodiment, DCI format X may include a set of TDD UL/DL configuration indicator (TCI) fields 1, 2, ..., N, where N is calculated by the UE using L format Y, where L _{format Y} is equal to the payload size of an existing DCI format Y before cyclic redundancy check (CRC) attachment, format Y is mapped onto the common search space (where the payload size of the DCI format size includes any padding bits appended to format Y), and R _others ≥ 0 is the number of information bits for other selected applications. In one embodiment, the selected application may be a transmit power control (TPC) command for a physical uplink shared channel (PUSCH) transmission on a flexible subframe.

In one embodiment, when the total number of bits of the N TCI fields is less than or equal to the selected DCI format size Y on the CSS, the bits are rounded down to the nearest integer. For example, in one embodiment, when L=17, R=0, M=3, and 2 bits are appended for DCI format X aligned with the DCI format Y size: 5 3-bit TCI fields are included in 17 bits.

In one embodiment, one or more information bits having a predetermined value of 0 or 1 may be appended to DCI format X until the payload size is equal to the payload size of DCI format Y. In one embodiment, information bits may be appended to DCI format X until the payload size of DCI format X is equal to the payload size of DCI format Y, where the number of bits of DCI format Y is bandwidth dependent. FIG5 shows an exemplary embodiment of a DCI format for UL/DL configuration indication. In one embodiment, DCI format Y may be DCI format 0/1A/3/3A that may be sent on the CSS of the PDCCH. In another embodiment, DCI format Y may be DCI format 1C that may be sent on the CSS of the PDCCH.

Figure 5 further illustrates that for a selected UE, the TDD UL/DL configuration of the serving cell can be jointly encoded with other TDD UL/DL configurations of other serving cells in a PDCCH with a DCI format X for UL/DL reconfiguration indication, wherein cyclic redundancy check (CRC) bits can be allocated for TDD-Config-RNTI scrambling for eIMTA operation. In one embodiment, when a UE group or multiple serving cells of a UE can receive dedicated independent TDD UL/DL configurations via the same TDD-Config-RNTI, an index of an M-bit TCI field for UL/DL configuration indication associated with the serving cell of the receiving UE can be provided. In one embodiment, M can be 3, or a larger or smaller TCI codeword can also be used.

Figure 6 shows a table depicting the encoding of the 3-bit target cell identity (TCI) codeword for TDD UL/DL configuration indication.One advantage of the 3-bit TCI may be that it provides a full range of flexibility for UL/DL reconfiguration.

In another embodiment, M may be 2. Figure 7 shows a table depicting the encoding of a 2-bit TCI codeword for TDD UL/DL configuration indication. For 2-bit TCI, the UL subframe according to the TDD UL/DL configuration indicated in the system information block type 1 (SIB1) message may be configured as a flexible subframe (FlexSF). In one embodiment, for 2-bit TCI, UL/DL reconfiguration is invisible to legacy UEs and adverse effects on radio resource management (RRM) measurements for legacy UEs may be avoided. One advantage of using 2-bit TCI is that the control overhead of the communication network is reduced. In one embodiment, for each TDD UL/DL configuration indicated in the SIB1 message, a set of UL/DL configurations associated with the 2-bit TCI field may be defined for UL/DL reconfiguration indication.

In one embodiment, the information element (IE) may be TDD-PDCCH-Config, where the TDD-PDCCH-Config may be used to specify one or more RNTIs and one or more indexes for flexible UL/DL configuration indication. In one embodiment, the TDD UL/DL reconfiguration function may be established or released using the IE. In another embodiment, the IE may be TDD-Config-RNTI, where the TDD-Config-RNTI may be the RNTI of the TDD UL/DL configuration indication using DCI format X. In another embodiment, the IE may be TDD-Config-Index with index K. TDD-Config-Index may be a parameter for indicating the index to the TDD UL/DL configuration field in DCI format X associated with the serving cell of the eIMAT-enabled UE. In one example, K may be 16.

FIG8 illustrates a signaling flow between a UE 802 and an Evolved Universal Terrestrial Radio Access Network (EUTRAN) 804 for establishing dynamic UL/DL configuration using an RRC Connection Setup message. When the EUTRAN 804 does not receive UE capabilities from the core network (e.g., when the UE 802 is in an Evolved Packet System (EPS) Mobility Management (EMM) DEREGISTERED mode), the EUTRAN 804 may request the UE 802 to provide the EUTRAN 804 with the capabilities of the UE 802 using a UE Capabilities Transfer procedure. The UE Capabilities Transfer may include step 0 (800): establishing an RRC connection between the UE 802 and the EUTRAN 804. After the RRC connection 800 is established between the UE 802 and the EUTRAN 804, the EUTRAN 804 may send a UE Capability Enquiry to the UE 802 in step 1 (810). When the UE capability query 810 is received by the UE 802, in step 2 (820), the UE 802 may send a UE capability information (UECapabilityInformation) message to the EUTRAN 804. The UE capability information message may indicate that the UE 802 supports the capability of TDD UL/DL reconfiguration.

In one embodiment, the IE may be PhyLayerParameter-v1240, wherein the PhyLayerParameter-v1240 indicates the UE capability of TDD UL/DL reconfiguration. The PhyLayerParameter-v1240 may be defined as follows:

In another embodiment, the IE may be TDD-configuration-r12, where the TDD-configuration-r12 indicates whether the UE 802 supports TDD UL/DL reconfiguration capability.

Steps 3-5a of Figure 8 illustrate the steps of the RCC connection establishment process between a UE with eIMTA capability and the EUTRAN to transmit parameters of the TDD UL/DL reconfiguration capability. In step 3 (830), the UE 802 may send an RRC connection request to the EUTRAN 804. In step 4a (840), when the EUTRAN 804 receives the UE capability of supporting eIMTA based on the flexible TDD UL/DL configuration, the IE TDD-PDCCH-Config may be included in the RCC connection establishment message. In one embodiment, the RCC connection establishment message may include: Radio Resource Configuration Dedicated information, Physical Configuration Dedicated information, and/or TDD-PDCCH-Config information. In one embodiment, when the TDD-PDCCH-Config IE is not included in the RCC connection establishment message, the UE 802 may follow the TDD UL/DL configuration process indicated in the System Information Block 1 (SIBl) to transmit and receive data. In step 5a (850), UE 802 may send an RRCConnectionComplete message to EUTRAN 804. In step 6 (860), when UE 802 receives the TDD-PDCCH-Config message including the TDD-Config-RNTI message and the TDD-Config-Index message, UE 802 may decode the PDCCH for DCI format X detection. In one embodiment, UE 802 may follow the relevant TDD UL/DL configuration indicated in DCI format X. In another embodiment, UE 802 may follow the TDD UL/DL configuration indicated in SIB1.

Step 7 (870) shows that for SCells in a CA scenario, E-UTRAN 804 can use dedicated signaling to provide the TDD-PDCCH-Config IE to UE 802 that supports TDD UL/DL reconfiguration when adding the SCell. When UE 802 receives TDD-PDCCH-Config, UE 802 can monitor the PDCCH with DCI format X, where the CRC is scrambled by the assigned TDD-Config-RNTI. In addition, when UE 802 receives TDD-PDCCH-Config, UE 802 can obtain the UL/DL configuration for the relevant serving cell when receiving DCI format X on the PDCCH based on the TDD-Config-Index. Step 8 (880) shows that UE 802 sends an RRCConnectionReconfigurationComplete message to EUTRAN 804.

In one embodiment, when eIMAT is used in the added secondary cell (SCell), step 7 (870), step 8 (880), and step 9 can be performed for a UE that can support both carrier aggregation (CA) and eIMTA. In one embodiment, in step 9 (890), for each SCell, when the UE 802 receives a TDD-PDCCH-Config message in the configuration of one SCell in step 8, the UE 802 can determine the UL/DL configuration by decoding the relevant TCI field in the DCI format X for the SCell. In one embodiment, the TDD-PDCCH-Config message can include a TDD-Config-RNTI message and a TDD-Config-Index message. In another embodiment, in step 9 (890), the UE 802 can determine the UL/DL configuration when receiving the DCI format X based on the received TDD-Config-r10 IE of the radio resource configuration common SCell-r10 (RadioResourceConfigCommonSCell-r10) for the SCell. In one embodiment, when no TDD-Config-RNTI is received, the UE may monitor and decode the PDCCH following the UL/DL configuration indicated in the SIB1.

FIG9 illustrates an alternative signaling flow between UE 902 and EUTRAN 904 for establishing a dynamic UL/DL configuration using an RRC Connection Reconfiguration message. Steps 0 through 2 are identical to the steps in FIG8 discussed in the previous paragraph. FIG9 does not include step 3 shown in FIG8. After UE 902 sends the UE Capability Information message to EUTRAN 904 in step 2, in step 4b (940), EUTRAN 904 sends an RRC Connection Reconfiguration message to UE 902. The RRC Connection Reconfiguration message may include a radio resource configuration-specific message and/or a physical configuration-specific TDD-PDCCH-Config message. In step 5b, UE 902 sends an RRC Connection Reconfiguration Complete message to EUTRAN 904. The remaining steps in FIG9 are identical to the steps discussed in the previous paragraph with respect to FIG8.

Figure 10 illustrates a PDCCH that may be used for DCI format X transmission. Figure 10 further illustrates that to search for DCI format X with a CRC scrambled with the RNTI assigned for eIMAT, a UE configured with UL/DL reconfiguration may monitor the CSS on the PDCCH in each non-DRX fixed DL subframe at aggregation levels 4 and 8 on a primary cell (PCell) according to the UL/DL configuration indicated in SIB1. In another embodiment, to search for DCI format X with a CRC scrambled with the RNTI assigned for eIMAT, a UE configured with UL/DL reconfiguration may monitor the CSS on the PDCCH in each non-DRX fixed DL subframe at aggregation level 8 on the PCell to reduce blind decoding attempts.

Figure 11 shows the CSS on the PDCCH for transmission of DCI format X. In this example, the UL/DL configuration information for the secondary cell (SCell) is carried on the DCI format X sent on the CSS of the PDCCH channel of the SCell. In one embodiment, the DCI format X may include an UL/DL configuration indication field for different serving cells, which may be connected to the DCI format X and sent on the PCell of the UE. In another embodiment, the DCI format X including the UL/DL configuration indication field for different serving cells may be deconstructed and sent on their own common search space of the PDCCH of the serving cell. Figure 11 further shows a DCI format X indicating that the UL/DL configuration of the PCell is sent using the CSS on the PDCCH of the PCell, and the UL/DL configuration of the SCell is encoded into another DCI format X that may be sent using the CSS on the PDCCH of the SCell. The benefit of sending the UL/DL configurations of different cells on the common search spaces of different serving cells is that it ensures that the UL/DL reconfiguration is available regardless of the backhaul delay between the two serving cells, as shown in the PCell and SCell in Figure 11.

Figure 12 shows a DCI format X including UL/DL configuration indication fields for different serving cells, where the DCI format is deconstructed into two separate DCI formats and mapped to different PDCCH channels in the CSS of the PCell. In one embodiment, different TDD-Config-RNTI values and the same DCI format size can be used to distinguish different DCI formats.

In one embodiment, DCI format X may be transmitted using a UE-specific search space (USS) on the PDCCH or enhanced PDCCH (EPDCCH). The PDCCH or EPDCCH may be determined by the assigned TDD-Config-RNTI configured by higher-layer signaling, as shown in Figures 8 and 9. In one embodiment, the locations of multiple USSs associated with different RNTIs may be on the PCell. In another embodiment, the locations of multiple USSs associated with different RNTIs may be on each serving cell for which the UL/DL configuration is intended, as indicated in DCI format X.

In one embodiment, the UE group common search space on the PDCCH can be associated with an assigned radio network temporary identifier (RNTI) value. For example, the RNTI value can be TDD-Config-RNTI. For each serving cell on which the physical downlink control channel (PDCCH) is monitored, the control channel element (CCE) corresponding to the PDCCH candidate m of the UE group common search space (S _k ^(L) ) with CCE aggregation level L in subframe k can be determined using the following formula:

Where _Yk is defined as:

Y _k =(A·Y _k-1 )mod D

Where i=0, ..., L-1 is the CCE index in aggregation level L,

Y _-1 = _nRNTI = tdd-Config-RNTI≠0, A = 39827, D = 65537 and where _ns is the slot number in the radio frame, the aggregation level L∈{1, 2, 4, 8} is defined by a set of PDCCH candidates, and N _CCE,k is the total number of control channel elements (CCEs) in the control region of subframe k. In one embodiment, in the PDCCH UE group-common search space of the serving cell on which the PDCCH is monitored, when the monitoring UE is configured with the carrier indicator field, m′=m+M ^(L) · _nCI , where _nCI is the carrier indicator field value and M ^(L) is the number of PDCCH candidates to be monitored in the UE-specific search space for aggregation level L. In another embodiment, when the monitoring UE is not configured with the carrier indicator field, m′=m, m=0, ..., M ^(L) -1 refers to the CCE index in the PDCCH with aggregation level L. M ^(L) is the number of PDCCH candidates to be monitored in the selected search space.

13 shows that when the UE is not configured for enhanced physical downlink control channel (EPDCCH) monitoring and the UE is not configured with a carrier indicator field, the UE may monitor one PDCCH UE group common search space at each of aggregation levels 1, 2, 4, 8.

Figure 14 shows that when the UE is not configured for EPDCCH monitoring and the UE is not configured with a carrier indicator field, a subset of aggregation levels on the PCell can be monitored. In another embodiment, each serving cell that supports the UL/DL reconfiguration function in a non-DRX fixed DL subframe or a portion of a non-DRX fixed subframe can be monitored. Figure 14 further shows PDCCH mapping, where the UE is configured with two serving cells, each of which supports the UL/DL reconfiguration function. In one embodiment, the control channel element (CCE) carrying the UL/DL reconfiguration PDCCH for the primary cell can be sent in the control region on the primary cell (PCell). In another embodiment, the CCE carrying the UL/DL reconfiguration PDCCH for the secondary cell can be sent in the control region of the secondary cell (SCell).

In one embodiment, the UE is configured to monitor the PDCCH UE-specific search space (USS) for flexible UL/DL reconfiguration information. In another embodiment, monitoring the reconfiguration PDCCH carrying flexible UL/DL reconfiguration may increase the total number of blind decoding attempts on the UE side due to the additional search space monitoring, unless the number of blind detections required in the UE-specific search space on the serving cell is reduced to keep the overall number of blind detections unchanged.

In one embodiment, the UE group common search space on the EPDCCH can be associated with an assigned RNTI value (e.g., TDD-Config-RNTI). Figure 15 shows an EPDCCH physical resource block (PRB) group configured to be shared by all UEs with EPDCCH monitoring capability. For a common EPDCCH-PRB group for DCI format X transmission (including a set of enhanced control channel elements (ECCEs) numbered from 0 to N _ECCE,p,k -1), the ECCE corresponding to the EPDCCH candidate m of the search space is given by:

in,

Y _p,k =(A·Y _p,k-1 )mod D, Y _-1 =n _RNTI =tdd-config-RNTI≠0, A=39827, A ₁ =39829, D=65537, and aggregation level L∈{1, 2, 4, 8, 16, 32} is defined by a set of EPDCCH candidates, Y _p,k is a variable Y value in EPDCCH-physical resource block-group p of subframe k, is an ECCE index number in aggregation level L, N _ECCE,p,k is the number of ECCEs in EPDCCH-PRB-group p of subframe k, is the number of EPDCCH candidates to be monitored at aggregation level L in EPDCCH-PRB-group p of the serving cell on which the EPDCCH is to be monitored, and b=n _CI when the carrier indicator field of the serving cell on which the UE is configured to monitor the EPDCCH, otherwise b=0; and n _CI is the carrier indicator field value, n _s is the time slot number in the radio frame.

In one embodiment, when the UE is configured to monitor the carrier indicator field of the serving cell on which the EPDCCH is performed, b = n _CI , where n _CI is the carrier indicator field value. In another embodiment, when the UE is not configured to monitor the carrier indicator field of the serving cell on which the EPDCCH is performed, b = 0. In one embodiment, the UE group common search space can be naturally distributed to obtain frequency and interference coordination diversity gains. In one embodiment, a UE configured with EPDCCH monitoring capability can support UL/DL reconfiguration.

Figure 16 illustrates a TDD UL/DL configuration supporting CoMP scenario 4, where each LPN or separate RRH cell shares the same physical cell ID as the macro cell. In one embodiment, in CoMP scenario 4, different TDD UL/DL configurations can be independently deployed at geographically separated RRHs. In one embodiment, in CoMP scenario 4, transmission points within a selected coverage area of a macro transmission point can share the same cell identity (cell ID) (e.g., cell ID 0 in Figure 16). In one example, the transmission points can be macro cells, pico cells, RRHs, and/or other types of low power nodes (LPNs).

In one embodiment, DCI format X transmissions from low-power RRHs with the same cell ID within a macrocell coverage area can be multiplexed in the time domain by assigning the DCI format X transmissions to different subframe offsets. In one embodiment, DCI format X transmissions can be assigned the same duty cycle or different duty cycles based on the data traffic conditions or backhaul characteristics used for the transmission. In another embodiment, the UL/DL configurations for different RRHs in CoMP scenario 4 can be signaled by different TCI fields in DCI format X transmissions. Different TCI fields in a DCI format X can provide a second dimension for TDD UL/DL configuration indication, in addition to providing time division multiplexing (TDM) over different subframe-based schemes. Figure 16 illustrates that UEs capable of UL/DL reconfiguration but associated with different transmission points (e.g., UE1, UE4, etc.) can be configured with independent UL/DL configurations based on traffic characteristics in each individual cell of the transmission point. In one embodiment, a single UL/DL reconfiguration PDCCH can be allowed to be transmitted after the UE indicates UL/DL reconfiguration capability to the EUTRAN.

When the UE indicates UL/DL reconfiguration capability to the EUTRAN, a set of parameters such as TDD-Config-RNTI and TDD-Config-Index may be transmitted or configured to the UE with UL/DL reconfiguration capability to help the UE monitor DCI format X. Figure 17 shows a table for the configuration of the TDD UL/DL reconfiguration indication. In one embodiment, the UE may decode the UE group common search space of DCI format X with a CRC, where the CRC is scrambled by the assigned RNTI value (i.e., TDD-Config-RNTI). When the UE decodes the UE group common search space, the UE may determine the UL/DL configuration of a serving cell based on the corresponding TCI index value (i.e., TDD-Config-Index) in DCI format X.

Figure 18 shows the UL/DL configuration in CoMP scenario 3 with CA enabled at each RRH. The UL/DL configuration in CoMP scenario 3 with CA enabled at each RRH can enable traffic adaptation across serving cells by allowing independent UL/DL configurations among different carriers and geographically different RRHs for CoMP and CA scenarios. Figure 18 also shows that for CoMP scenario 3, the RRHs can be configured as cells with cell IDs. In one embodiment, for CoMP scenario 4, the RRHs can be configured to share the same cell ID with the macro cell. Figure 18 also shows seven different TDD UL/DL configurations (TDD UL/DL configurations 0-6) that allow various downlink-uplink ratios (i.e., 40% to 90% DL ratio) and switching periodicities (i.e., 5ms and 10ms). As shown in FIG18 , the serving cell deployed on carrier 0 of RRH 0 has higher UL traffic than the serving cell deployed on carrier 1, so RRH 0 is configured with UL/DL configuration 2 on carrier 0 and UL/DL configuration 5 on carrier 1 (because the latter configuration provides more DL resources than the former).

FIG19 shows a table of a set of TDD UL/DL configurations for TDD UL/DL reconfiguration indication. TDD UL/DL reconfiguration configuration parameters (e.g., RNTI or UL/DL configuration index (i.e., TDD-Config-Index) in DCI format X) can be conveyed to UEs (e.g., UE 0 and UE 1) via higher layer signaling. In one embodiment, the RNTI value can be used across two RRHs for CA-enabled CoMP scenario 3. In another embodiment, two different RNTI values (e.g., RNTI X and RNTI Y) or different TDD-Config-Index configurations can be assigned to UE 0 and UE 1 to enable independent UL/DL configuration for each serving cell. In one embodiment, TDD-Config-Index can be provided by higher layers and used to determine the index to the UL/DL configuration of the serving cell for the selected UE.

Another example provides functionality 2000 of a computer circuit of a UE operable to dynamically change an uplink/downlink (UL/DL) configuration in a communication network (as shown in the flowchart of FIG. 20 ). The functionality can be implemented as a method, or the functionality can be executed on a machine as instructions, wherein the instructions are included on at least one computer-readable medium or a non-transitory machine-readable storage medium. The computer circuit can be configured to dynamically change an uplink/downlink (UL/DL) configuration in a communication network (as shown in block 2010). The computer circuit can be further configured to transmit a UE capability information element (IE) to an eNode B indicating the UE's enhanced interference mitigation and traffic adaptation (eIMTA) capability, thereby supporting eIMTA time duplex domain (TDD) UL/DL reconfiguration functionality (as shown in block 2020). The computer circuit can also be configured to receive eIMTA configuration information in an RRC Connection Setup message or an RRC Connection Reconfiguration message at the UE (as shown in block 2030).

In one embodiment, the RRC connection establishment message or the RRC connection reconfiguration message may include a 2-bit or 3-bit UL/DL configuration indicator field index in a UL/DL reconfiguration physical downlink control channel (PDCCH) associated with the serving cell and an eIMTA radio network temporary identifier (RNTI). In one embodiment, the computer circuitry may be configured to attempt to decode the UL/DL reconfiguration PDCCH with a cyclic redundancy check (CRC) (wherein the CRC is scrambled by the assigned eIMTA-RNTI) and determine the UL/DL configuration information from the decoded UL/DL reconfiguration PDCCH based on the assigned indicator index.

In one embodiment, the computer circuitry may be configured to monitor one common search space (CSS) on a primary cell (PCell) to receive an UL/DL reconfiguration PDCCH with a CRC scrambled by an eIMTA-RNTI assigned for a UE. In one embodiment, the computer circuitry may be configured to monitor one common search space (CSS) on a primary cell (PCell) to receive an UL/DL reconfiguration PDCCH with a CRC scrambled by a plurality of different eIMTA-RNTIs, each of which is mapped one-to-one to a serving cell index. In one embodiment, the computer circuitry may be configured to monitor the common search space (CSS) on each eIMTA-enabled serving cell to receive an UL/DL reconfiguration PDCCH with a CRC scrambled by an eIMTA-RNTI assigned for a UE.

In one embodiment, the computer circuitry may be configured to monitor a UE group common search space on a PDCCH on a primary cell (PCell) or each eIMTA enabled serving cell to receive an UL/DL reconfiguration PDCCH with a CRC scrambled with a different eIMTA-RNTI for each serving cell allocated for the UE, wherein a control channel element (CCE) corresponding to a PDCCH candidate m of the UE group common search space is determined using the following formula:

Where the aggregation level L∈{1, 2, 4, 8} is defined by a set of PDCCH candidates and _Yk is determined using the following formula:

Y _k =(A·Y _k-1 )mod D

Wherein, Y ₋₁ =n _RNTI ≠ 0, A=39827, D=65537, and n _s is the slot number in the radio frame, and the RNTI value for n _RNTI is the eIMTA-RNTI allocated for UL/DL reconfiguration PDCCH transmission.

In one embodiment, when the monitoring UE is not configured with a carrier indicator field, m′=m.

In one embodiment, m′=m+M ^(L) · _nCI , _nCI is the carrier indicator field value, m=0,…,M ^(L) -1, M ^(L) is the number of PDCCH candidates to be monitored in the UE-specific search space for aggregation level L, N _CCE,k is the total number of CCEs in the control region of subframe k, and i=0,…,L-1 is the CCE index in aggregation level L.

In one embodiment, the computer circuitry may be configured to monitor a UE group common search space on an enhanced PDCCH (EPDCCH) on a PCell only when cross-carrier scheduling is configured or on each eIMTA-enabled serving cell when cross-carrier scheduling is not configured to receive an UL/DL reconfiguration PDCCH with a CRC scrambled by multiple different eIMTA-RNTIs allocated for the UE, wherein an enhanced control channel element (ECCE) corresponding to an EPDCCH candidate m of the search space may be given by:

Wherein, Yp _,k is defined as follows and i=0, ..., L-1

Y _{p, k} = (A·Y _{p, k-1} ) mod D

where aggregation level L∈{1, 2, 4, 8, 16, 32} is defined by a set of EPDCCH candidates, Yp _,k is the variable Y value in EPDCCH-physical resource block-group p of subframe k, is the ECCE index number in aggregation level L, _NECCE,p,k is the number of ECCEs in EPDCCH-PRB-group p of subframe k, is the number of EPDCCH candidates monitored at aggregation level L in EPDCCH-PRB-group p for the serving cell on which the EPDCCH will be monitored, b= _nCI if the carrier indicator field of the serving cell on which the UE is configured to monitor EPDCCH, otherwise b=0; and _nCI is the carrier indicator value.

In one embodiment, the UL/DL reconfiguration PDCCH includes N TDD UL/DL configuration indicator (TCI) fields, where N may be configured by the eNode B in the RCC signaling message for each eIMTA-capable UE, or N may be determined using where L _{format Y} is the payload size of the existing downlink control information (DCI) format Y before CRC attachment, R _others ≥ 0 is the number of information bits for the selected function, M is the payload size of each UL/DL configuration indicator in the UL/DL reconfiguration PDCCH, and format Y is mapped onto the common search space.

In one embodiment, the selected functionality includes a transmit power control (TPC) command for a physical uplink shared channel (PUSCH) transmission on a flexible subframe. In another embodiment, zero padding information bits may be appended to the TDD UL/DL configuration indicator field until the UL/DL reconfiguration PDCCH size is equal to the format Y size mapped to the common search space.

Another example provides functionality 2100 of a computer circuit of an eNode B operable to dynamically change a time duplex domain (TDD) uplink/downlink (UL/DL) configuration in a communication network (as shown in the flowchart of FIG. 21 ). The functionality can be implemented as a method, or the functionality can be executed on a machine as instructions, wherein the instructions are included on at least one computer-readable medium or a non-transitory machine-readable storage medium. The computer circuit can be configured to establish a radio resource control connection with a user equipment (UE) (as shown in block 2210). The computer circuit can also be configured to receive a UE capability information element (IE) indicating the enhanced interference mitigation and traffic adaptation (eIMTA) capability of the UE from the UE (as shown in block 2120). The computer circuit can also be configured to determine, based on the UE capability information IE, that the UE supports the eIMTA functionality (as shown in block 2130). The computer circuit can also be configured to configure radio resource control (RRC) parameters for performing eIMTA UL/DL reconfiguration of the UE (as shown in block 2140).

In one embodiment, the computer circuitry may be configured to transmit to the UE eIMTA parameters associated with a secondary cell (SCell) of the eNode B. In another embodiment, the RRC parameters may include the UE's eIMTA Radio Network Temporary Identity (RNTI) and an indicator index.

FIG22 illustrates a method for dynamically changing the uplink/downlink ratio in a communication network using a flowchart 2200. The method may include, at block 2210, requesting a radio resource control (RRC) connection with an enhanced Node B (eNode B). The method may also include, at block 2220, transmitting a user equipment (UE) capability information message to the eNode B to indicate the UE's enhanced interference mitigation and traffic adaptation (eIMTA) capability, thereby supporting eIMTA time duplex domain (TDD) UL/DL reconfiguration functionality. The method may also include, at block 2230, receiving, at the UE, eIMTA configuration information in an RRC connection establishment message or an RRC connection reconfiguration message.

In one embodiment, the RRC connection establishment message or the RRC connection reconfiguration message includes a 2-bit or 3-bit UL/DL configuration indicator field index and an eIMTA radio network temporary identifier (RNTI) in an UL/DL reconfiguration physical downlink control channel (PDCCH) associated with the serving cell. In another embodiment, the UL/DL reconfiguration physical downlink control channel (PDCCH) includes N TCI fields, where N can be configured by the eNode B in an RRC signaling message for each eIMTA-capable UE, or N can be determined using, where L _{format Y} is the payload size of the existing downlink control information (DCI) format Y before CRC attachment, R _others ≥ 0 is the number of information bits used for the selected function, M is the size of the target cell identifier (TCI) codeword in the UL/DL reconfiguration PDCCH, and format Y is mapped onto the common search space.

In one embodiment, the existing DCI format Y mapped to the common search space may be DCI format 1C. In another embodiment, the existing DCI format Y mapped to the common search space may be DCI format 0/1A/3/3A. In another embodiment, the TCI codeword size M may be 3 bits, and each TCI codeword may be a different UL/DL configuration. In another embodiment, the UL/DL reconfiguration PDCCH mapped to the common search space may be configured to enable independent UL/DL configuration for each serving cell in a single carrier scenario, coordinated multi-point (CoMP) scenario 3, CoMP scenario 4, carrier aggregation (CA) scenario, and CA and CoMP combination scenario.

In one embodiment, the method may further include: receiving, at the UE, an indicator index and eIMTA configuration parameters associated with a secondary cell (SCell) of the UE, and determining, based on the received indicator index in a received UL/DL reconfiguration PDCCH, a UL/DL configuration for the SCell. In another embodiment, the UL/DL configuration indicator field in the UL/DL reconfiguration PDCCH may be 2 bits or 3 bits. In one embodiment, the method may further include: sending a DCI format in all system information block 1 (SIB1) DL subframes, and determining the UL/DL configuration at a discontinuous reception (DRX) UE when the DRX UE is in a flexible subframe.

FIG23 also provides an illustration of a microphone and one or more speakers that can be used for audio input and output from the wireless device. The display screen can be a liquid crystal display (LCD) screen, or other types of display screens such as organic light emitting diode (OLED) displays. The display screen can be configured as a touch screen. The touch screen can use capacitive, resistive, or other types of touch screen technology. An application processor and a graphics processor can be coupled to internal memory to provide processing and display capabilities. A non-volatile memory port can also be used to provide data input/output options to the user. The non-volatile memory port can also be used to expand the memory capacity of the wireless device. A keyboard can be integrated with the wireless device or wirelessly connected to the wireless device to provide additional user input. A virtual keyboard can also be provided using the touch screen.

Various technologies or some aspects or parts thereof can take the form of program code (that is, instruction) embodied in a tangible medium such as a floppy disk, CD-ROM, hard drive, non-transient computer-readable storage medium, or any other machine-readable storage medium, wherein, when the program code is loaded into a machine such as a computer and executed by the machine, the machine becomes a device for implementing various technologies. In the case where the program code on a programmable computer is executed, a computing device can include a processor, a storage medium (including volatile and non-volatile memory and/or storage element) readable by the processor, at least one input device, and at least one output device. Volatile and non-volatile memory and/or storage element can be RAM, EPROM, flash drive, optical drive, magnetic hard drive, or other media for storing electronic data. Base station and mobile station can also include a transceiver module, a counter module, a processing module, and/or a clock module or a timer module. One or more programs that can implement or utilize the various technologies described herein can use an application program interface (API), reusable controls, etc. These programs can be implemented with high-level programs or object-oriented programming languages to communicate with a computer system. However, one or more programs may be implemented in assembly language or machine language as desired. In any case, the language may be a compiled or interpreted language and may be combined with hardware implementations.

It should be understood that many of the functional units described in this specification have been labeled as modules to more prominently emphasize their implementation independence. For example, a module can be implemented as a hardware circuit including a custom VLSI circuit or gate array, a finished semiconductor such as a logic chip, a transistor, or other discrete components. A module can also be implemented as a programmable hardware device such as a field programmable gate array, programmable array logic, or a programmable logic device.

Module can also be implemented as software, for various types of processor execution.Identified executable code module can comprise for example, one or more physical or logical blocks of computer instructions, and these physical or logical blocks can be organized as objects, processes, or functions.Yet the executable file of the identified module does not need to be physically located together, but can comprise different instructions stored in different locations, and these instructions comprise this module when being logically combined and realize the claimed purpose of this module.

In fact, the module of executable code can be a single instruction or a lot of instructions, can even be distributed in a plurality of different code segments of the different programs across a plurality of memory devices.Similarly, operational data can be identified and be shown in the module, and can be embodied in any appropriate form and organized with the data structure of any appropriate type.Operational data can be collected as a single data group, or can be distributed on different locations (comprising being distributed on different storage devices), and can only be present in a system or network as an electronic signal at least in part.Module can be an active or passive module comprising an agent that can operate to perform the function expected.

References throughout the specification to "an example" mean that a particular feature, structure, or characteristic described in connection with the example is included in at least one embodiment of the present invention. Therefore, the appearances of the phrase "in an example" in various places throughout the specification are not necessarily all referring to the same embodiment.

For the purpose of convenience, multiple projects, structural elements, constituent elements, and/or materials used herein can be presented in a common list. However, these lists should be understood as if each element of the list is identified as a separate or unique element respectively. So, in the absence of contrary instructions, each corresponding element of the list should not be understood as the equivalence of any other element of the same list only because it is presented in a common group. In addition, various embodiments of the present invention and examples can be referenced together with the replacement of its various components. It should be understood that these embodiments, examples, and replacement should not be understood as equivalence to each other, but should be considered as independent and autonomous representation of the present invention.

In addition, described feature, structure or characteristic can be combined in one or more embodiments in any appropriate manner.In the following description, provide multiple details (for example, the example of layout, distance, network example), to provide a thorough understanding of the embodiment of the present invention.But those skilled in the art will recognize that the present invention can be implemented under the situation that does not have one or more of these details, or can utilize other methods, components, layout etc. to be implemented.In other examples, do not show or describe known structure, material, or operation in detail, to avoid confusing aspects of the present invention.

Although the foregoing examples illustrate the principles of the present invention in one or more specific applications, it will be apparent to those skilled in the art that various modifications in form, use, and details of the embodiments can be made without departing from the principles and concepts of the present invention and without inventive effort. Therefore, the present invention is limited only by the appended claims.

Claims (23)

1. An evolved Node B (eNB) apparatus operable to reconfigure Time Division Duplex (TDD) uplink and downlink UL/DL configurations for a User Equipment (UE), the apparatus comprising one or more processors and a memory configured to perform the following operations: A set of configuration indication fields numbered 1 to N is determined, the set of configuration indication fields being included in the downlink control information DCI format Y carried on the physical downlink control channel PDCCH, wherein L _{format Y} is equal to the payload size of the DCI format Y, and M is the number of bits in each indication field; The DCI format Y is mapped onto the common search space CSS of the PDCCH for transmission to the UE; The PDCCH is encoded using a Cyclic Redundancy Check (CRC) scrambled with the enhanced interference mitigation and traffic-adaptive eIMTA radio network temporary identifier RNTI for the UE; and The eNB's transceiver is notified via a signal to send the encoded PDCCH to the UE. 2. The apparatus of claim 1 is further configured to signal the transceiver of the eNB to send a UL/DL configuration instruction for TDD reconfiguration to the UE. 3. The apparatus of claim 1, wherein the DCI format Y is format 1C. 4. The apparatus of claim 1, wherein M = 3. 5. The apparatus of claim 1 is further configured to append one or more bits with predefined values of zero to the set of configuration indication fields until the total number of bits of the N configuration indication fields is equal to the payload size of the DCI format Y. 6. The apparatus of claim 1 is further configured to signal the transceiver of the eNB to send the eIMTA-RNTI to the UE so that the UE can decode the physical downlink control channel (PDCCH). 7. The apparatus of claim 1, further configured to indicate to the UE an index of the set of configuration indication fields numbered 1 to N, and a time-domain duplex (TDD) UL-DL configuration index of the serving cell using Radio Resource Control (RRC) signaling. 8. The apparatus of claim 1, wherein the eNB is configured to decode an indication from the UE indicating that the UE supports TDD UL-DL reconfiguration functionality. 9. A user equipment (UE) apparatus operable to reconfigure time-division duplex (TDD) uplink and downlink UL/DL configurations, the apparatus including one or more processors and memories configured to perform the following operations: The UE processes uplink and downlink UL/DL configuration indications for TDD reconfiguration received from the eNB, the UL/DL configuration indications including: A set of configuration indication fields numbered 1 to N, which are included in the downlink control information (DCI) format Y carried on the physical downlink control channel (PDCCH), where L _{format Y} is equal to the payload size of the DCI format Y, and M is the number of bits in each indication field; and The UE decodes the encoded PDCCH received from the eNB, wherein the DCI format Y is mapped onto the common search space CSS of the PDCCH, and wherein the PDCCH is encoded using cyclic redundancy check (CRC) scrambled with the enhanced interference mitigation and traffic adaptation eIMTA radio network temporary identifier RNTI for the UE. 10. The apparatus of claim 9, further comprising a transceiver configured to: Receive the UL/DL configuration instruction from the eNB; and Receive the encoded PDCCH from the eNB. 11. The apparatus of claim 9, wherein the DCI format Y is format 1C. 12. The apparatus of claim 9, wherein M = 3. 13. The apparatus of claim 9, wherein one or more bits having a predefined value of zero are appended to the set of configuration indicator fields until the total number of bits in the N configuration indicator fields equals the payload size of the DCI format Y. 14. The apparatus of claim 9, further configured to receive eIMTA-RNTI from the eNB, wherein the UE is configured to decode the encoded PDCCH using the eIMTA-RNTI. 15. The apparatus of claim 9, further configured to receive from the eNB an indication of an index for a time-domain duplex (TDD) UL-DL configuration index for a serving cell using Radio Resource Control (RRC) signaling. 16. The apparatus of claim 9 is further configured to signal the transceiver of the eNB to send an indication to the eNB, wherein the indication indicates that the UE supports the TDD UL-DL reconfiguration function. 17. The apparatus of claim 9, wherein the UE includes an antenna, a touch-sensitive display, a speaker, a microphone, a graphics processor, an application processor, internal memory, or a non-volatile memory port. 18. At least one machine-readable storage medium having instructions presented thereon for modifying uplink/downlink UL/DL configurations at a user equipment (UE) in a communication network, the instructions performing the following operations when executed: Use one or more processors at the UE to request a Radio Resource Control (RRC) connection with the eNodeB; The one or more processors at the UE are used to signal UE capability information elements (IEs) to be transmitted to the eNodeB, wherein the UE capability IEs indicate the UE's enhanced interference mitigation and traffic adaptation eIMTA capabilities to support eIMTA time-domain duplex (TDD) UL/DL reconfiguration functionality; and The one or more processors at the UE are used to process eIMTA configuration information received from the eNodeB via Radio Resource Control (RRC) messages, wherein the eIMTA configuration information is received in response to a signal notifying the eNodeB of the UE's capability IE. 19. The at least one machine-readable storage medium of claim 18, wherein the RRC message includes the eIMTA radio network temporary identifier RNTI. 20. The at least one machine-readable storage medium of claim 19, further comprising instructions that, when executed, perform the following operations: Attempt to decode the UL/DL reconfigured PDCCH using a cyclic redundancy check (CRC) scrambled with the assigned eIMTA-RNTI; and The UL/DL reconfiguration information is determined from the decoded UL/DL reconfiguration PDCCH based on the assigned indicator field index. 21. The at least one machine-readable storage medium of claim 20, wherein the UL/DL reconfiguration PDCCH comprises N TDD UL/DL configuration indicator TCI fields, wherein N is determined by usage, wherein L _{format Y} is the payload size of the existing downlink control information DCI format Y before CRC appending, R _others ≥ 0 is the number of information bits used for the selected function, M is the payload size of each UL/DL configuration indicator within the UL/DL reconfiguration PDCCH, and format Y is mapped to a common search space. 22. The at least one machine-readable storage medium of claim 21, wherein zero-padding information bits are appended to the TDD UL/DL configuration indicator field until the UL/DL reconfigures the PDCCH size to be equal to the format Y size mapped onto the common search space. 23. The at least one machine-readable storage medium of claim 19, further comprising instructions, when executed, to: monitor a common search space (CSS) on the primary cell PCell to receive the UL/DL reconfigured PDCCH having a CRC scrambled by the eIMTA-RNTI assigned to the UE.