HK1181597B - Resource partitioning information for enhanced interference coordination - Google Patents

Description

Resource partitioning information for enhanced interference coordination

Cross Reference to Related Applications

Priority of this application claims priority of U.S. provisional patent application No.61/323,756, filed 4/13/2010, U.S. provisional patent application No.61/387,886, filed 9/29/2010, and U.S. provisional patent application No.61/387,878, filed 9/29/2010, all of which are incorporated herein by reference.

Technical Field

Certain aspects of the present disclosure generally relate to wireless communications, and more particularly, to partitioning resources for enhanced inter-cell interference coordination (elcic).

Background

Wireless communication networks have been widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast, and so on. These wireless networks may be multiple-access networks capable of supporting multiple users by sharing the available network resources. Examples of such multiple-access networks include Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, orthogonal FDMA (ofdma) networks, and single carrier FDMA (SC-FDMA) networks.

A wireless communication network may include a plurality of base stations capable of supporting communication for a plurality of User Equipments (UEs). A UE may communicate with a base station via the downlink and uplink. The downlink (or forward link) refers to the communication link from the base stations to the UEs, and the uplink (or reverse link) refers to the communication link from the UEs to the base stations.

A base station may transmit data and control information to a UE on the downlink and/or may receive data and control information from a UE on the uplink. On the downlink, transmissions from a base station may observe interference due to transmissions from neighbor base stations. On the uplink, transmissions from a UE may cause interference to transmissions from other UEs communicating with neighbor base stations. This interference can degrade performance on both the downlink and uplink.

Disclosure of Invention

Certain aspects of the present disclosure generally relate to partitioning resources for enhanced inter-cell interference coordination (elcic). Certain aspects include: broadcasting a message indicating time domain Resource Partitioning Information (RPI), wherein a User Equipment (UE) may operate in an idle mode. With RPI, the UE is able to identify protected resources with reduced/eliminated interference from neighboring cells. The RPI in the broadcast message may be encoded as a bitmap, either in place of or in addition to the enumerated U/N/X subframes. Other aspects call for transmitting a dedicated or unicast message indicating the time domain RPI, wherein the UE may operate in a connected mode. With RPI, a UE may be able to determine Channel State Information (CSI), make Radio Resource Management (RRM) measurements, or perform Radio Link Monitoring (RLM) from one or more signals from a serving base station during protected time domain resources.

In one aspect of the invention, a method for wireless communication is provided. The method generally includes: acquiring a Sequential Frame Number (SFN); one or more protected subframes that comply with a cooperative resource allocation between a serving node B and at least one non-serving node B, and unprotected subframes that do not comply with the cooperative resource allocation are determined from the SFN.

In one aspect of the invention, an apparatus for wireless communication is provided. The apparatus generally comprises: means for obtaining a Sequential Frame Number (SFN); means for determining one or more protected subframes that are compliant with a cooperative resource allocation between a serving node B and at least one non-serving node B and unprotected subframes that are not compliant with the cooperative resource allocation from the SFN.

In one aspect of the invention, a method for wireless communication is provided. The method generally includes: receiving, at a User Equipment (UE), an indication of time domain Resource Partitioning Information (RPI) corresponding to a time domain resource allocation between a serving access point and one or more non-serving access points in a heterogeneous network; and identifying one or more protected time domain resources from the time domain RPI, the one or more protected time domain resources being time domain resources that are restricted from use by an interfering access point.

In one aspect of the invention, a method for wireless communication is provided. The method generally includes: participating in time domain resource division in a heterogeneous network; and transmitting an indication of a time domain RPI identifying one or more protected time domain resources that are time domain resources restricted from use by an interfering access point.

In one aspect of the invention, an apparatus for wireless communication is provided. The apparatus generally comprises: means for receiving an indication of a time domain RPI corresponding to a time domain resource allocation between a serving access point and one or more non-serving access points in a heterogeneous network; and means for identifying one or more protected time domain resources from the time domain RPI, the one or more protected time domain resources being time domain resources that are restricted from use by an interfering access point.

In one aspect of the invention, an apparatus for wireless communication is provided. The apparatus generally comprises: means for participating in time domain resource partitioning in a heterogeneous network; and means for transmitting an indication of a time domain RPI, the time domain RPI to identify one or more protected time domain resources, the one or more protected time domain resources being time domain resources that are restricted from use by an interfering access point.

In one aspect of the invention, an apparatus for wireless communication is provided. The apparatus generally comprises: a receiver to receive an indication of a time domain RPI corresponding to a time domain resource allocation between a serving access point and one or more non-serving access points in a heterogeneous network; and at least one processor configured to identify one or more protected time domain resources from the time domain RPI, the one or more protected time domain resources being time domain resources restricted from use by an interfering access point.

In one aspect of the invention, an apparatus for wireless communication is provided. The apparatus generally comprises: at least one processor configured to participate in time domain resource partitioning in a heterogeneous network; and a transmitter. The transmitter is generally configured to transmit an indication of a time domain RPI identifying one or more protected time domain resources that are time domain resources restricted for use by an interfering access point.

In one aspect of the invention, a computer program product for wireless communication is provided. The computer program product generally includes a computer-readable medium having code for: receiving, at a UE, an indication of a time domain RPI corresponding to a time domain resource allocation between a serving access point and one or more non-serving access points in a heterogeneous network; and identifying one or more protected time domain resources from the time domain RPI, the one or more protected time domain resources being time domain resources that are restricted from use by an interfering access point.

In one aspect of the invention, a computer program product for wireless communication is provided. The computer program product generally includes a computer-readable medium having code for: participating in time domain resource division in a heterogeneous network; and transmitting an indication of a time domain RPI identifying one or more protected time domain resources that are time domain resources restricted from use by an interfering access point.

Various aspects and features of the disclosure are described in further detail below.

Drawings

Fig. 1 is a block diagram conceptually illustrating an example of a wireless communication network in accordance with certain aspects of the present invention.

Fig. 2 is a block diagram conceptually illustrating an example of a frame structure in a wireless communication network, in accordance with certain aspects of the present invention.

Fig. 2A is a block diagram conceptually illustrating an example of uplink allocation of resources, in accordance with certain aspects of the present invention.

Fig. 3 is a block diagram conceptually illustrating an example of a node B communicating with User Equipment (UE) in a wireless communication network, in accordance with certain aspects of the present invention.

Fig. 4 illustrates an exemplary heterogeneous network in accordance with certain aspects of the invention.

Fig. 5 illustrates exemplary resource partitioning in a heterogeneous network, in accordance with certain aspects of the present invention.

Fig. 6 illustrates an exemplary cooperative partitioning of subframes in a heterogeneous network in accordance with certain aspects of the subject innovation.

Fig. 7 is a functional block diagram conceptually illustrating exemplary blocks performed to determine protected subframes that comply with cooperative resource allocation, in accordance with certain aspects of the present invention.

Fig. 8A-8C illustrate exemplary structures for transmitting bitmap information for conveying protected time domain resources in accordance with certain aspects of the present invention.

Figure 9 is a functional block diagram conceptually illustrating exemplary blocks executed to receive broadcast information indicating protected resources in a heterogeneous network, in accordance with certain aspects of the present invention.

Figure 10 is a functional block diagram conceptually illustrating exemplary blocks executed to broadcast information indicative of protected resources, in accordance with certain aspects of the present invention.

Fig. 11 illustrates restricted measurement resources signaled to UEs associated with a macro cell using common resources for all cells in accordance with certain aspects of the subject innovation.

Figure 12 is a functional block diagram conceptually illustrating exemplary blocks performed to determine and signal a subset of time domain resource allocations for performing certain measurements, in accordance with certain aspects of the present invention.

Figure 13 is a functional block diagram conceptually illustrating exemplary blocks performed to identify protected time domain resources from received time domain Resource Partitioning Information (RPI), in accordance with certain aspects of the present invention.

Figure 14 is a functional block diagram conceptually illustrating exemplary blocks performed to use time domain resource partitioning in a heterogeneous network, in accordance with certain aspects of the present invention.

Detailed Description

The techniques described herein may be used for various wireless communication networks such as CDMA, TDMA, FDMA, OFDM, SC-FDMA and other networks. The terms "network" and "system" are generally used interchangeably. A CDMA network may implement a radio technology such as Universal Terrestrial Radio Access (UTRA), CDMA 2000, etc. UTRA includes wideband CDMA (wcdma) and other variants of CDMA. cdma 2000 covers IS-2000, IS-95 and IS-856 standards. TDMA networks may implement wireless technologies such as global system for mobile communications (GSM). OFDMA systems may implement methods such as evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-And the like. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS). 3GPP Long Term Evolution (LTE) and LTE-advanced (LTE-A) are new versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE-A, and GSM are described in documents from an organization named "3 rd Generation partnership project" (3 GPP). From the name "3 rd generation partnership project 2"Cdma 2000 and UMB are described in documents of the organization of (3 GPP 2). The techniques described herein may be used for the wireless networks and wireless technologies described above, as well as other wireless networks and wireless technologies. For clarity, certain aspects of the techniques are described below for LTE, and LTE terminology is used extensively in the following description.

Exemplary Wireless network

Fig. 1 shows a wireless communication network 100, which may be an LTE network. Wireless network 100 may include several evolved node bs (enbs) 110 and other network entities. An eNB may be a station that communicates with User Equipment (UE) and may also be referred to as a base station, a node B, an access point, etc. Each eNB110 may provide communication coverage for a particular geographic area. The term "cell" may refer to a coverage area of an eNB and/or an eNB subsystem serving the coverage area, depending on the context in which the term is used.

An eNB may provide communication coverage for a macro cell, pico cell, femto cell, and/or other types of cells. A macro cell may cover a relatively large geographic area (e.g., a range of several kilometers radius) and allow unrestricted access by UEs with service subscriptions. A pico cell may cover a relatively small geographic area and allow unrestricted access by UEs with service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and allow restricted access by UEs associated with the femto cell (e.g., UEs in a Closed Subscriber Group (CSG), UEs of in-home users, etc.). The enbs of the macro cell may be referred to as macro enbs. An eNB for a pico cell may be referred to as a pico eNB. An eNB of a femto cell may be referred to as a femto eNB or a home eNB. In the example shown in fig. 1, enbs 110a, 110b, and 110c may be macro enbs for macro cells 102a, 102b, and 102c, respectively. eNB110 x may be a pico eNB for pico cell 102 x. enbs 110y and 110z may be femto enbs for femto cells 102y and 102z, respectively. An eNB may support one or more (e.g., three) cells.

Wireless network 100 may also include relay stations. A relay station is a station that receives a transmission of data and/or other information from an upstream station (e.g., an eNB or UE) and sends a transmission of data and/or other information to a downstream station (e.g., a UE or eNB). The relay station may also be a UE that relays transmissions for other UEs. In the example shown in fig. 1, relay 110r may communicate with eNB110 a and UE120 r to facilitate communication between eNB110 a and UE120 r. A relay station may also be referred to as a relay eNB, relay, etc.

Wireless network 100 may be a heterogeneous network including different types of enbs (e.g., macro enbs, pico enbs, femto enbs, relays, etc.). These different types of enbs may have different transmit power levels, different coverage areas, and different effects on interference in wireless network 100. For example, macro enbs may have a higher transmit power level (e.g., 20 watts), while pico enbs, femto enbs, and relays may have a lower transmit power level (e.g., 1 watt).

Wireless network 100 may support synchronous or asynchronous operation. For synchronous operation, enbs may have similar frame timing, and transmissions from different enbs may be approximately aligned in time. For asynchronous operation, enbs may have different frame timing, and transmissions from different enbs may not be aligned in time. The techniques described herein may be used for both synchronous and asynchronous operations.

Network controller 130 may couple to a set of enbs and provide coordination and control for these enbs. Network controller 130 may communicate with eNB110 over a backhaul. The enbs 110 may also communicate with each other, e.g., directly or indirectly through a wireless or wired backhaul.

UEs 120 may be dispersed throughout wireless network 100, and each UE may be fixed or mobile. A UE may also be referred to as a terminal, mobile station, subscriber unit, station, etc. A UE may be a cellular telephone, a Personal Digital Assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless telephone, a Wireless Local Loop (WLL) station, a tablet, etc. The UE may communicate with a macro eNB, pico eNB, femto eNB, relay, etc. In fig. 1, a solid line with double arrows indicates the desired transmission between a UE and a serving eNB designated to serve the UE on the downlink and/or uplink. The dashed line with double arrows indicates interfering transmissions between the UE and the eNB.

LTE employs Orthogonal Frequency Division Multiplexing (OFDM) on the downlink and single carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers, which are collectively referred to as tones, bins (bins), and so on. Each subcarrier may be modulated with data. Generally, modulation symbols are transmitted in the frequency domain with OFDM and in the time domain with SC-FDMA. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may depend on the system bandwidth. For example, K may be equal to 128, 256, 512, 1024 or 2048 for a system bandwidth of 1.25, 2.5, 5, 10 or 20 megahertz (MHz), respectively. The system bandwidth may also be divided into sub-bands. For example, a sub-band may cover 1.08MHz, and there may be 1, 2, 4, 8, or 16 sub-bands for a system bandwidth of 1.25, 2.5, 5, 10, or 20MHz, respectively.

Fig. 2 shows a frame structure used in LTE. The transmission timeline for the downlink may be divided into units of radio frames. Each radio frame may have a predetermined duration (e.g., 10 milliseconds (ms)), and each radio frame may be divided into 10 subframes with indices of 0 through 9. Each subframe may include two slots. Thus, each radio frame may include 20 slots with indices of 0 through 19. Each slot may include L symbol periods, e.g., L =7 symbol periods for a normal cyclic prefix (as shown in fig. 2), or L =6 symbol periods for an extended cyclic prefix. Indexes 0 to 2L-1 may be allocated to 2L symbol periods in each subframe. The available time-frequency resources may be divided into resource blocks. Each resource block may cover N subcarriers (e.g., 12 subcarriers) in one slot.

In LTE, an eNB may transmit a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) for each cell in the eNB. The primary and secondary synchronization signals may be transmitted in symbol periods 6 and 5, respectively, in each of subframes 0 through 5 of each radio frame with the normal cyclic prefix, as shown in fig. 2. The UE may use the synchronization signal for cell detection and acquisition. The eNB may transmit a Physical Broadcast Channel (PBCH) in symbol periods 0 to 3 in slot 1 of subframe 0. The PBCH may carry certain system information.

The eNB may transmit a Physical Control Format Indicator Channel (PCFICH) in the first symbol period of each subframe, as shown in fig. 2. The PCFICH may convey the number of symbol periods (M) used for the control channel, where M may be equal to 1, 2, or 3, or may vary from subframe to subframe. For smaller system bandwidths (e.g., having less than 10 resource blocks), M may also be equal to 4. The eNB may transmit a Physical HARQ Indicator Channel (PHICH) and a Physical Downlink Control Channel (PDCCH) in the first M symbol periods of each subframe. The eNB may transmit a Physical HARQ Indicator Channel (PHICH) and a Physical Downlink Control Channel (PDCCH) (not shown in fig. 2) in the first M symbol periods of each subframe. The PHICH may carry information to support hybrid automatic repeat request (HARQ). The PDCCH may carry information on resource allocation for the UE and control information for a downlink channel. The eNB may transmit a Physical Downlink Shared Channel (PDSCH) in the remaining symbol periods of each subframe. The PDSCH may carry data for UEs scheduled for data transmission on the downlink.

The eNB may transmit the PSS, SSS, and PBCH in the center 1.08MHz of the system bandwidth used by the eNB. The eNB may transmit the PCFICH and PHICH over the entire system bandwidth in each symbol period used to transmit the PCFICH and PHICH channels. The eNB may send PDCCH to the set of UEs in certain portions of the system bandwidth. The eNB may transmit the PDSCH to a particular UE in a particular portion of the system bandwidth. The eNB may transmit the PSS, SSS, PBCH, PCFICH, and PHICH to all UEs in a broadcast form, may transmit the PDCCH to a specific UE in a unicast form, and may also transmit the PDSCH to a specific UE in a unicast form.

There may be several resource units available in each symbol period. Each resource element may cover one subcarrier in one symbol period and may be used to transmit one modulation symbol, which may be real or complex valued. Resource elements that are not used for reference signals in each symbol period may be arranged into Resource Element Groups (REGs). Each REG may include four resource elements in one symbol period. The PCFICH may occupy four REGs in symbol period 0, where the four REGs may be approximately evenly spaced in frequency. The PHICH may occupy three REGs in one or more configurable symbol periods, where the three REGs may be spread over frequency. For example, the three REGs for the PHICH may all belong to symbol period 0, or may be spread in symbol period 0, symbol period 1, and symbol period 2. The PDCCH may occupy 9, 18, 36, or 72 REGs in the first M symbol periods, where the REGs may be selected from available REGs. Only certain combinations of REGs may be allowed for PDCCH.

The UE may know specific REGs for PHICH and PCFICH. The UE may search for different REG combinations for the PDCCH. The number of combinations used for the search is typically less than the number of combinations allowed for the PDCCH. The eNB may send the PDCCH to the UE in any one of the combinations that the UE will search for.

Fig. 2A is a block diagram conceptually illustrating an example of an uplink allocation 200A of resources (e.g., corresponding to uplink in LTE) in accordance with certain aspects of the present disclosure. The resource blocks available for uplink may be divided into a data portion and a control portion. The control section may be formed at both edges of the system bandwidth and may have a configurable size. The resource blocks in the control portion may be allocated to the UE for transmission of control information. The data portion may include all resource blocks not included in the control portion. The design in fig. 2 results in the data portion including contiguous subcarriers, which may allow all of the contiguous subcarriers in the data portion to be allocated to a single UE.

The resource blocks in the control portion may be allocated to the UE for transmitting control information to the eNB. The resource blocks in the data portion may also be allocated to the UE for transmitting data to the eNB. The UE may send control information in a Physical Uplink Control Channel (PUCCH) 210 on the resource blocks allocated in the control portion. The UE may transmit data in a Physical Uplink Shared Channel (PUSCH) 220 on the allocated resource blocks in the data portion, or transmit both data and control information. As shown in fig. 2A, the uplink transmission may span both slots of a subframe, or may hop in frequency.

The UE may be in the coverage of multiple enbs. One of the enbs may be selected to serve the UE. The serving eNB may be selected according to various criteria, such as received power, path loss, signal-to-noise ratio (SNR), and so on.

The UE may operate in a dominant interference scenario, where the UE may observe high interference from one or more interfering enbs. A significant interference scenario may occur due to limited relevance. For example, in fig. 1, UE120 y may be close to femto eNB110 y and may have a higher received power for eNB110 y. However, UE120 y may not be able to access femto eNB110 y due to the restricted association and thus connect to macro eNB110 c at a lower received power (as shown in fig. 1), or connect to femto eNB110 z at a lower received power as well (not shown in fig. 1). Then, UE120 y may observe high interference from femto eNB110 y on the downlink and may also cause high interference to eNB110 y on the uplink.

A dominant interference scenario may also occur due to range extension, which is a scenario where: the UE connects to an eNB with lower path loss and lower SNR among all ebns detected by the UE. For example, in fig. 1, UE120 x may detect macro eNB110 b and pico eNB110 x and may have a lower received power for eNB110 x than eNB110 b. However, if the path loss for eNB110 x is lower than the path loss for macro eNB110 b, then UE120 x is expected to be connected to pico eNB110 x. This may cause less interference to the wireless network for a given data rate for UE120 x.

In an aspect, communication in a dominant interference scenario may be supported by having different enbs operate on different frequency bands. A frequency band is a range of frequencies that may be used for communication and may be given by (i) a center frequency and a bandwidth or (ii) a lower frequency and an upper frequency. A frequency band may also be referred to as a band, a frequency channel, etc. The frequency bands of the different enbs may be selected such that a UE may communicate with a weaker eNB in a dominant interference scenario while allowing a stronger eNB to communicate with its UE. An eNB may be classified as a "weak" eNB or a "strong" eNB based on the relative received power of signals received from the eNB at the UE.

Fig. 3 shows a block diagram of a design of a base station or eNB110 and a UE120 (which may be one of the base station/eNB and UE in fig. 1). For the restricted association scenario, eNB110 may be macro eNB110 c in fig. 1 and UE120 may be UE120 y. The eNB110 may also be some other type of base station. The eNB110 may be equipped with T antennas 334a through 334T and the UE120 may be equipped with R antennas 352a through 352R, where T ≧ 1 and R ≧ 1.

At the eNB110, a transmit processor 320 may receive data from a data source 312 and control information from a controller/processor 340. The control information may be for PBCH, PCFICH, PHICH, PDCCH, etc. The data may be for PDSCH, etc. Transmit processor 320 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The transmit processor 320 may also generate reference symbols (e.g., for PSS, SSS) and cell-specific reference signals. A Transmit (TX) multiple-input multiple-output (MIMO) processor 330 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide T output symbol streams to T Modulators (MODs) 332a through 332T. Each modulator 332 may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator 332 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. T downlink signals from modulators 332a through 332T may be transmitted through T antennas 334a through 334T, respectively.

At UE120, antennas 352a through 352r may receive downlink signals from eNB110 and may provide received signals to demodulators (DEMODs) 354a through 354r, respectively. Each demodulator 354 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator 354 may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 356 may obtain received symbols from all R demodulators 354a through 354R and, if applicable, perform MIMO detection on the received symbols and provide detected symbols. A receive processor 358 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for UE120 to a data sink 360, and provide decoded control information to a controller/processor 380.

On the uplink, at UE120, a transmit processor 364 may receive and process data from a data source 362 (e.g., for the PUSCH) and may receive and process control information from a controller/processor 380 (e.g., for the PUCCH). The transmit processor 364 may also generate reference symbols for a reference signal. The symbols from transmit processor 364 may be precoded by a TX MIMO processor 366 if applicable, further processed by modulators 354a through 354r (e.g., for SC-FDM, etc.), and transmitted to eNB 110. At the eNB110, the uplink signals from the UE120 may be received by antennas 334, processed by demodulators 332, detected by a MIMO detector 336, and further processed by a receive processor 338 to obtain the decoded data and control information transmitted by the UE120, if applicable. Receive processor 338 may provide the decoded data to a data sink 339 and the decoded control information to controller/processor 340.

Controllers/processors 340, 380 may direct the operation at eNB110 and UE120, respectively. Controller/processor 340 and/or other processors and modules at eNB110 may perform or direct the operations of block 1000 in fig. 10, and/or other processes for the techniques described herein. Controller/processor 380 and/or other processors and modules at UE120 may also perform or direct the operations of block 700 in fig. 7, block 900 in fig. 9, and/or other processes for the techniques described herein. Memories 342, 382 may store data and program codes for eNB110 and UE120, respectively. A scheduler 344 may schedule UEs for data transmission on the downlink and/or uplink.

Exemplary resource partitioning

According to certain aspects of the present disclosure, when a network supports enhanced inter-cell interference coordination (elcic), base stations may negotiate with each other to coordinate resources in order to reduce/eliminate interference by interfering cells relinquishing part of their resources. With elcic or similar techniques, the UE may access the serving cell using the resources relinquished by the interfering cell, otherwise the UE would experience severe interference.

For example, a femto cell with a closed access mode within the coverage of an open macro cell (i.e., only member femto UEs may access the cell) may create a coverage hole for the macro cell. By having the femto cell relinquish some of its resources, a macro UE under the femto cell coverage area may access the UE's serving macro cell by using the resources relinquished by the femto cell.

In wireless access systems using OFDM (e.g., E-UTRAN), the resources relinquished by the interfering cells may be time-based, frequency-based, or a combination of both. When the relinquished resources are time-based, the interfering cell does not use some of the subframes in the time domain. When the relinquished resources are based on frequency, the interfering cell does not use some of the subcarriers in the frequency domain. When the relinquished resources are a combination of both frequency and time, the interfering cell does not use some of the resources defined by frequency and time.

Fig. 4 illustrates an example of a scenario in which eICIC may allow a macro UE120 y supporting eICIC to access a macro cell 110c (as shown by the full radio link 402) even when the macro UE120 y is under severe interference from the femto cell 110y (e.g., a release 10 macro UE shown in fig. 4). Under severe interference from the femtocell 110y, a conventional macro UE120u (e.g., a release 8 macro UE shown in fig. 4) may not be able to access the macrocell 110c (as shown by the broken radio link 404). Femto UE120 v (e.g., a release 8 femto UE shown in fig. 4) may access femto cell 110y without any interference issues from macro cell 110 c.

According to certain aspects, resource partitioning between base stations may be accomplished on a time basis. As an example, for E-UTRAN, the resources may be divided by subframes.

According to certain aspects, the network may support enhanced interference coordination, where there may be different sets of partitioning information. The first of these sets may be referred to as semi-Static Resource Partitioning Information (SRPI). The second of these sets may be referred to as Adaptive Resource Partitioning Information (ARPI). As the name implies, the SRPI does not change often, and the SRPI may be sent to the UE so that the UE may use this resource partitioning information for its own operation.

For example, the resource partition may have a period of 8ms (8 subframes) or a period of 40ms (40 subframes). For the downlink (e.g., from cell node B to UE), the partition pattern may be mapped to a known subframe (e.g., the first subframe of each radio frame with a System Frame Number (SFN) value of a multiple of 4). Accordingly, the mapping may be applied to determine resource partitioning information for a particular subframe. An example of a downlink may be

Index_{SRPI_DL}= (SFN x 10+ subframe number) mod 8

For the uplink, the SRPI map may be shifted, e.g., by 4 ms. Thus, an example for the uplink may be

Index_{SRPI_UL}= (SFN x 10+ subframe number +4) mod 8

The SRPI may use the following three values for each entry:

u (use): the value indicates that the subframe has been sorted out from the dominant interference for use by the cell (i.e., the primary interfering cell does not use the subframe);

n (not used): the value indicates that the subframe should not be used; and

x (unknown): the value indicates that the subframe is not statically partitioned. The details of resource usage negotiation between base stations are unknown to the UE.

Another possible set of parameters for the SRPI may be as follows.

U (use): the value indicates that the subframe has been sorted out from the dominant interference for use by the cell (i.e., the primary interfering cell does not use the subframe);

n (not used): the value indicates that the subframe should not be used;

x (unknown): the value indicates that the subframe is not statically partitioned (and details of resource usage negotiation between base stations are unknown to the UE); and

c (public): the value may indicate that all cells may use the subframe without resource partitioning. The subframe may be subject to interference so that the base station may choose to use the subframe only for UEs that are not under severe interference.

The SRPI of the serving cell may be broadcast over the air. In the E-UTRAN, the SRPI of the serving cell may be transmitted in one of a Master Information Block (MIB) or a System Information Block (SIB). The predefined SRPI may be defined according to characteristics of cells, e.g., macro cells, pico cells (with open access), and femto cells (with closed access). In this case, encoding the SRPI in the overhead message may result in more efficient broadcasting over the air.

The base station may also broadcast the SRPI of the neighbor cell in one of the SIBs. To this end, the SRPI may be sent with its corresponding range of Physical Cell Identities (PCIs).

The ARPI may represent further resource partitioning information with detailed information for the "X" subframe in the SRPI. As described above, the detailed information for the "X" subframe is typically only known to the base station.

Fig. 5 and 6 show examples of SRPI allocation as described above in scenarios with macro cells and femto cells.

Exemplary broadcast of resource partitioning information

Figure 7 is a functional block diagram conceptually illustrating exemplary blocks 700 that may be performed to determine protected subframes that comply with cooperative resource allocation in accordance with the subject matter of the present disclosure. Block 700 may be performed, for example, by a UE or a node B to determine protected subframes from an SFN. At 702, an SFN may be acquired. At block 704, one or more protected subframes that comply with cooperative resource allocation between a serving node B and at least one non-serving node B can be determined from the SFN. One or more unprotected subframes that do not comply with the cooperative resource allocation may also be determined at block 704.

Certain aspects of the present disclosure provide techniques for using SRPI for enhanced interference coordination. The term "femto" as used in this application generally refers to a closed home enhanced node b (henb) having a Closed Subscriber Group (CSG) to which a UE is not allowed access if the UE is not a member of the CSG. In a macro-femto scenario, non-member UEs (served by a macro cell) may be protected from femto cell interference and allowed to access the macro cell.

The term "pico cell" as used in this application generally refers to an open access eNB with less transmit power. Also, the term "CRE" as used in this application generally refers to cell range extension, where a pico cell is used to extend the range of a macro cell. In a macro-pico scenario, it is desirable to coordinate the interference so that the pico can serve its UEs over an extended geographic area, with possibly moderate Handover (HO) bias.

According to certain aspects, resources may be limited to the time domain. In some cases, the protected resources may correspond to any resources that are restricted from being used by the interfering cell (or potential interfering cell). For example, during protected subframes, the interfering cells may be restricted to required transmissions, such as almost blank subframes (ABSFs, also known as ABSs), which may be restricted to reference signals, synchronization signals, and/or certain control signals. Resources that are not restricted for use by the interfering cell (or potentially interfering cell) may be considered unprotected resources.

As described above, when the network supports enhanced interference coordination, the base stations negotiate with each other to coordinate resources in order to reduce/eliminate interference by the interfering cells relinquishing a portion of their time and/or frequency resources. As described above, fig. 4 illustrates an exemplary "macro-femto" scenario in which eICIC may allow an eICIC-enabled macro UE120 y (e.g., a release 10 macro UE in the figure) to access a macro cell even when it is under severe interference from femto cell 110 y.

Another scenario to consider is the "macro-pico" case with Cell Range Extension (CRE), where the UE is served by a weaker pico cell. In such a scenario, the macro cell may relinquish some time domain resources (e.g., subframes in E-UTRA) so that the UE may be served by the weaker pico cell.

In much of the present description, the resource partitioning between base stations may be time-based (e.g., for E-UTRAN, the resources are partitioned by sub-frames). However, those skilled in the art will appreciate that the techniques presented herein may also be performed using a cooperative partitioning of frequency resources, or a cooperative partitioning of a combination of both time and frequency resources.

When the network supports enhanced interference coordination using time domain resource partitioning, the network may broadcast information about which time domain resources idle mode UEs should use to implement mobility functions such as cell selection and reselection. According to certain aspects, a UE may use statically negotiated or allocated Almost Blank Subframes (ABSFs) of an aggressor (i.e., a cell causing strong interference), especially when the UE is under severe interference from the aggressor.

According to certain aspects, Resource Partitioning Information (RPI) may be broadcast, such as ABSF of a femto. According to certain aspects, the information may be encoded in the SIB or MIB as a bitmap. The bitmap may be broadcast instead of, or in addition to, broadcasting the resource partitioning information (i.e., enumerated in U/N/X) as described above with reference to FIG. 5.

According to certain aspects, the information may be broadcast using an Information Element (IE). For example, as shown in fig. 8A, a new IE may be defined in SIB1/2, for example, in the macro-femto case. This IE may be considered to indicate "secure resources under strong interference from closed CSG". The description of usage and related behavior in this manner may be limited to the macro-femto scenario. In the illustrated example, bit 2 indicates the ABSF of the femto cell.

In the macro-pico case (with CRE) shown in fig. 8B, IEs may be included in the broadcast, which have a very similar or identical format as the macro-femto case. In the macro-pico case, the IE may be considered to indicate "security resources under strong interference of cell range extension". In the example shown, bit 2 indicates the ABSF of the pico cell. If an idle mode UE camped on a macro cell does not attempt to detect a weak femto cell, but the UE that was once connected to the pico cell may remain in the pico Extended Boundary Area (EBA) in idle mode, this may be broadcast only by the pico cell (and not by the macro cell).

Another possible scheme (as shown in fig. 8C) is to define two different IEs (e.g., for macro SIB1/2, the IE may be defined as "intruder's ABSF", while the IE in femto SIB1/2 may be defined as "own ABSF"). This difference can distinguish the former (macro SIB 1/2) (intended for use by UEs camping on the macro cell) from the latter (femto SIB 1/2) (intended for use only by non-member UEs that cannot camp on the cell).

As proposed in the present application, various signaling of resource partitioning may be performed in heterogeneous networks, benefiting UEs in idle mode from performing utility functions. As described above, bitmap information (e.g., ABSF of aggressor cells) may be broadcast (e.g., instead of or in place of what is enumerated based on the SRPI shown in fig. 5). As shown in fig. 8A-8C, this may be common information between two associated cells (i.e., the same information is broadcast in both femto and macro-femto scenarios).

The UE may use the bitmap information only under certain conditions. For example, "security resources under strong interference from a closed CSG" may be used only when a UE served by a macro cell is under severe interference from a femto cell, while "security resources under strong interference of cell range extension" may be used by a UE camped on a weak pico cell. This scheme may require the use of two IEs, but may allow forward compatibility for macro-pico scenarios.

Figure 9 is a functional block diagram conceptually illustrating an exemplary block 900 executed to receive broadcast information indicating protected resources in a heterogeneous network, in accordance with certain aspects of the present invention. Block 900 may be performed, for example, by a UE. In block 902, the UE may receive a broadcast message including information regarding time domain resources. The time domain resource is determined from a cooperative partitioning of resources between a serving access point and one or more non-serving access points of the heterogeneous network. In block 904, the UE may identify one or more protected time domain resources in which to restrict use of interfering access points based on the information.

As described above, the UE may use these protected time domain resources for idle mode mobility functions such as cell selection and reselection. As described above, the protected resources may correspond to Almost Blank Subframes (ABSFs) of static negotiations or allocations of aggressor access points (e.g., access points of cells that are causing strong interference). It is particularly desirable to use these protected resources when the UE is under severe interference from an intruder.

Figure 10 is a functional block diagram conceptually illustrating exemplary blocks 1000 executed to broadcast information indicative of protected resources, in accordance with certain aspects of the present invention. Block 1000 may be performed, for example, by an access point (e.g., a macro, femto, or pico eNB) in a heterogeneous network. At block 1002, an access point may participate in cooperative partitioning of time domain resources of a heterogeneous network. The partitioning may include: active negotiation between access points, or simply receiving resource partitioning information from, for example, another access point. At block 1004, the access point may broadcast a message including information identifying one or more protected time domain resources of the heterogeneous network in which interfering access point usage is restricted.

RRM/RLM measurements for enhanced inter-cell interference coordination

For certain aspects of the present disclosure, the network may utilize dedicated Radio Resource Control (RRC) signaling to signal information about which resources a connected mode UE may use to perform Radio Resource Management (RRM) and Radio Link Monitoring (RLM) measurements for enhanced interference coordination. For example, in a macro-femto scenario, non-member UEs may be protected and allowed to access a macro cell. As another example, in a macro-pico scenario, interference may need to be coordinated so that the pico cell may better serve its UEs, with a possible appropriate Handover (HO) bias.

The UE may perform RRM/RLM measurements using any subframes (e.g., non-MBSFN (non-multimedia broadcast over single frequency network) subframes). However, for proper operation of eICIC in heterogeneous networks, the UE may use specific resources (e.g., subframes) for making measurements for RRM/RLM. For example, for connected mode RRM/RLM measurements, the UE may use dedicated RRC signaling for measurement configuration.

As will be described further below, for certain aspects, the resource partitioning between base stations may be based on time. For example, resources may be divided by subframes (e.g., for E-UTRAN). For other aspects, the resource partitioning between base stations may be based on frequency or a combination of time and frequency. When the network supports enhanced interference coordination using time domain resource partitioning, the network may signal information about which resources a connected mode UE may use for RRM/RLM measurements via dedicated RRC signaling. The UE may use statically negotiated or allocated Almost Blank Subframes (ABSFs) of an aggressor (i.e., a cell causing strong interference), especially when the UE is under severe interference from the aggressor. For certain aspects, the ABSF may be an N subframe.

For certain aspects, the restricted measurement resources signaled to the UE may comprise the same set of restricted resources for all cells. The restricted resource set may be contained in a measurement object IE in an RRC message. For other aspects, the restricted measurement resources signaled to the UE may include different sets of resources according to different cells (e.g., according to cell types, such as macro/femto/pico). For example, the set of resources may be configured for each Physical Cell Identity (PCI). As another example, a set of resources may be configured for a range of PCIs.

For certain aspects, the eNB may always configure restricted measurement resources. For other aspects, the eNB may configure the restricted measurement resources according to radio conditions reported by the UE (e.g., in a heterogeneous network).

Combinations of the above described embodiments may be used. For example, the restricted measurement resources signaled to the UE may include using common resources for all cells, where the restricted measurement resources may be based on radio conditions reported by the UE. As another example, the restricted measurement resources signaled to the UE may include using different resources according to cell type, wherein the restricted measurement resources may always be configured by the eNB.

Fig. 11 illustrates a restricted measurement resource signaled to a UE120 y associated with a macro cell 102c using common resources for all cells. As shown in fig. 11, pico cell 102p and femto cell 102y may be located within the coverage area of macro cell 102 c. When UE120 y is not in close proximity to femtocell 102y, UE120 y may be configured to use N subframes (i.e., N subframes) of macrocell 102c_macro) Performing RRM/RLM measurements to detect the picocell 102p, where N_macroProtected subframes (i.e., U) with pico cell 102p_pico) And (4) correlating. However, when UE 102y enters the coverage area of the femto cell (or is in close proximity thereto), macro cell 102c may use the restricted resources to configure new measurements. Thus, UE120 y may be configured to use N subframes (i.e., N) of femto cell 102y_femto) Performing RRM/RLM measurements, wherein N_femtoMay be other than N_macroThe subframe of (2). In other words, UE120 y may use another set of restricted resources when it is not very close to the coverage area of femtocell 102 y.

For certain aspects, measurement resources for RRM and RLM may be configured commonly. This may ensure that the UE may correctly declare a Radio Link Failure (RLF) from RLM when it cannot perform appropriate RRM measurements. For other aspects, the measurement resources for RRM and RLM may be configured separately. Further, the eNB may utilize Channel State Information (CSI) reports from the UE (i.e., when the UE reports different CSI values for protected and unprotected resources) to infer whether the UE is in strong interference.

Figure 12 is a functional block diagram conceptually illustrating exemplary blocks 1200 performed to determine and signal a subset of time domain resource allocations for performing certain measurements, in accordance with certain aspects of the present invention. Block 1200 may be performed, for example, by a base station or eNB110 to signal resources to a UE to perform RRM/RLM measurements for eICIC. In block 1202, a base station may determine time domain resources for a Radio Resource Management (RRM) or Radio Link Management (RLM) procedure. The time domain resources are determined according to a cooperative partitioning of resources between a serving access point and one or more non-serving access points. At block 1024, the base station may signal the UE with a subset of time domain resources for performing measurements at the UE.

Generic resource partitioning for eICIC

Figure 13 is a functional block diagram conceptually illustrating exemplary blocks 1300 that are performed to identify protected time domain resources from received time domain Resource Partitioning Information (RPI), in accordance with certain aspects of the present invention. Block 1300 may be performed, for example, by UE 120.

At block 1302, the UE may receive an indication of a time domain RPI. The time domain RPI may correspond to a time domain resource allocation between a serving access point and one or more non-serving access points in a heterogeneous network (HetNet).

At block 1304, the UE may identify one or more protected time domain resources from the time domain RPI. The one or more protected time domain resources are time domain resources that limit usage by an interfering access point.

For certain aspects, the one or more protected time domain resources may include an Almost Blank Subframe (ABS) associated with the interfering access point. For certain aspects, the time domain RPI may include a bitmap with one or more bits set to a value indicating one or more protected time domain resources. For certain aspects, the one or more protected time domain resources may be common to the serving access point and the one or more non-access points.

For certain aspects, the indication of the time domain RPI may be received from a serving access point. For certain aspects, the interfering access point may be one of the non-serving access points, and the one or more protected time domain resources may be associated with the serving access point. The interfering access point may be associated with a Closed Subscriber Group (CSG) to which the UE does not belong. For other aspects, the interfering access point may be a serving access point and the protected time domain resources may correspond to a non-serving access point.

For certain aspects, the indication of the time domain RPI may be received in a broadcast message. The UE may receive the broadcast message while it is in idle mode. The time domain RPI may be broadcast in a System Information Block (SIB). For certain aspects, the UE may receive a neighbor list from a serving access point. The neighbor list carries the time domain RPI in the SIB. For certain aspects, the time domain RPI in the broadcast message may be associated with a first access point that is different from a second access point that sent the broadcast message, the first access point and the second access point being in a heterogeneous network. For other aspects, the time domain RPI in the broadcast message may be associated with the same access point that transmitted the broadcast message.

For certain aspects, the UE may receive a broadcast message from a serving access point including a time domain RPI, the time domain RPI corresponding to the serving access point. The UE may identify the protected resources by obtaining one or more protected time domain resources for one or more non-serving access points based on the protected time domain resources for the serving access point. For certain aspects, the obtaining may include: the one or more protected time domain resources for the one or more non-serving access points are considered the same as the protected time domain resources for the serving access point. For other aspects, the obtaining may include: one or more protected time domain resources for one or more non-serving access points are considered supplemental to the protected time domain resources for the serving access point.

For certain aspects, the indication of the time domain RPI may include at least one of a dedicated message or a unicast message. The UE may receive the dedicated message or the unicast message when it is in the connected mode. For certain aspects, the UE may determine a received power of a reference signal from a serving access point during one or more protected time domain resources.

For certain aspects, the UE may optionally determine a received power of a Reference Signal (RS) from a serving access point during one or more protected time domain resources at block 1306. For certain aspects, the UE may selectively perform at least one of the following during the one or more protected time domain resources based on one or more signals from the serving access point, at block 1308: (1) determining Channel State Information (CSI); (2) performing Radio Resource Management (RRM) measurements; or (3) perform Radio Link Monitoring (RLM). For certain aspects, the protected time domain resources for RRM are the same as the protected time domain resources for RLM. In this case, a single Information Element (IE) may be used to indicate protected time domain resources for both RRM and RLM.

For certain aspects, the UE may receive the indication of the time domain RPI by: the method includes receiving a first IE indicating first protected time domain resources associated with a serving access point and receiving a second IE indicating second protected time domain resources associated with at least one of non-serving access points. The second IE may include a cell Identification (ID) of each of at least one of the non-serving access points. For certain aspects, the UE may determine Channel State Information (CSI), make Radio Resource Management (RRM) measurements, and/or perform Radio Link Monitoring (RLM) during the second protected time domain resource based on one or more signals from at least one of the non-serving access points.

Fig. 14 is a functional block diagram conceptually illustrating an exemplary block 1400 executed to use time domain resource partitioning in a HetNet, in accordance with certain aspects of the present invention. Block 1400 may be performed, for example, by a base station or eNB 110.

At block 1402, a base station may participate in time domain resource partitioning in a HetNet. At block 1404, the base station may transmit an indication of a time domain RPI identifying one or more protected time domain resources. The one or more protected time domain resources are time domain resources that limit usage by an interfering access point.

For certain aspects, the one or more protected time domain resources may include an Almost Blank Subframe (ABS) associated with the interfering access point. The time domain RPI may include a bitmap with one or more bits set to a value indicating one or more protected time domain resources. For certain aspects, the time domain resources may be jointly partitioned for a serving access point and one or more non-serving access points in a heterogeneous network.

For certain aspects, the base station may transmit the indication of the time domain RPI by broadcasting the indication. The time domain RPI may be broadcast in a System Information Block (SIB), such as in one or more Information Elements (IEs) of the SIB, or in a Master Information Block (MIB). For certain aspects, an indication of the time domain RPI may be broadcast from an access point associated with one or more protected time domain resources. For certain aspects, an indication of a time domain RPI may be broadcast from a first access point, and one or more protected time domain resources may be associated with a second access point different from the first access point.

For certain aspects, the base station may send the indication using a dedicated message or a unicast message. An indication of the time domain RPI may be sent to a User Equipment (UE) operating in a connected mode.

For certain aspects, the base station may optionally transmit Reference Signals (RSs) to the UE at 1406. At 1408, the base station can receive an indication of a received power of a reference signal determined during one or more protected time domain resources from the UE.

For certain aspects, the base station may optionally transmit one or more signals to the UE at 1410. At 1412, the base station may receive an indication of CSI based on the one or more signals determined during the one or more protected time domain resources from the UE.

The protected time domain resources may be used by the UE for Radio Resource Management (RRM) or Radio Link Management (RLM) procedures. For certain aspects, the protected time domain resources for RRM may be the same as the protected time domain resources for RLM.

For certain aspects, the base station may optionally receive a report from the UE indicating radio conditions. The base station may determine one or more protected time domain resources identified by the time domain RPI based on the report and the time domain resource partitioning. The radio conditions may include information about the proximity of the UE to one or more non-serving access points. The protected time domain resources may include time domain resources partitioned for one or more non-serving access points or for a serving access point.

For certain aspects, the base station may send the indication by: the method includes transmitting a first IE indicating first protected time domain resources associated with a first access point in a heterogeneous network and transmitting a second IE indicating second protected time domain resources associated with one or more second access points different from the first access point. The first access point or the second access point may be a base station that transmits an indication of the time domain RPI.

For certain aspects, the protected time domain resources may depend on a Physical Cell Identity (PCI) of the access point being measured. The protected time domain resources may be configured for a range or set of PCIs. The range or set of PCIs may correspond to a power class of the access point or to access permissions of the access point.

The various operations of the methods described above may be performed by any suitable module capable of performing the corresponding functions. These modules may include various hardware and/or software components and/or devices, including but not limited to, circuits, Application Specific Integrated Circuits (ASICs), or processors. For example, the means for transmitting or the means for transmitting may include: the transmitter, modulator 354, and/or antenna 352 of UE120 shown in fig. 3; or the transmitter, modulator 332, and/or antenna 334 of eNB110 shown in fig. 3. The means for receiving may comprise: the receiver, demodulator 354, and/or antenna 352 of UE120 shown in fig. 3; or the receiver, demodulator 332, and/or antenna 334 of eNB110 shown in fig. 3. The means for processing, means for determining, means for identifying, means for operating, means for performing, and/or means for participating may comprise a processing system that may include at least one processor, such as transmit processor 320, receive processor 338, or controller/processor 340 of eNB110 shown in fig. 3, or receive processor 358, transmit processor 364, or controller/processor 380 of UE120 shown in fig. 3.

Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

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

The various illustrative logical blocks, modules, and circuits described in connection with the disclosure herein may be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The steps of a method or algorithm described in connection with the teachings herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

In one or more exemplary aspects, the functions described herein may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a general purpose or special purpose computer. Further, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source via a coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes Compact Disc (CD), laser disc, optical disc, Digital Versatile Disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the present invention is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (150)

1. A method for wireless communication, comprising:

receiving, at a User Equipment (UE), an indication of a time domain Resource Partitioning Information (RPI) corresponding to a subframe allocation between a serving access point and one or more non-serving access points in a heterogeneous network, wherein the indication of the time domain RPI comprises:

a second information element, IE, for indicating a second protected subframe associated with at least one of the non-serving access points; or

The second IE and a first IE indicating a first protected subframe associated with the serving access point; and

identifying one or more protected subframes from the time domain RPI, the one or more protected subframes being subframes that limit usage by an interfering access point.

2. The method of claim 1, wherein the one or more protected subframes comprise Almost Blank Subframes (ABSs) associated with the interfering access point.

3. The method of claim 1, wherein the time domain RPI comprises a bitmap with one or more bits set to a value indicating the one or more protected subframes.

4. The method of claim 1, wherein the indication of the time domain RPI is received from the serving access point.

5. The method of claim 1, wherein the interfering access point is one of the non-serving access points, and wherein the one or more protected subframes are associated with the serving access point.

6. The method of claim 5, wherein the interfering access point is associated with a Closed Subscriber Group (CSG) to which the UE does not belong.

7. The method of claim 1, wherein the indication of the time domain RPI is received in a broadcast message.

8. The method of claim 7, wherein the time domain RPI in the broadcast message is associated with a first access point that is different from a second access point that transmitted the broadcast message, the first access point and the second access point being in the heterogeneous network.

9. The method of claim 7, wherein the time domain RPI is broadcast in a system information block, SIB.

10. The method of claim 9, further comprising: receiving a neighbor list from the serving access point, wherein the neighbor list carries the time domain RPI in the SIB.

11. The method of claim 7, wherein the receiving comprises: receiving the broadcast message from the serving access point including the time domain RPI corresponding to the serving access point, and wherein the identifying comprises: obtaining the one or more protected subframes for the one or more non-serving access points from the protected subframes for the serving access point.

12. The method of claim 11, wherein the obtaining comprises: treat the one or more protected subframes for the one or more non-serving access points to be the same as the protected subframes for the serving access point.

13. The method of claim 7, wherein the receiving comprises: receiving the broadcast message from the one or more non-serving access points, the broadcast message including a time domain RPI related to the one or more protected subframes for the one or more non-serving access points.

14. The method of claim 13, wherein the broadcast message comprises a system information block type 1(SIB1) from the one or more non-serving access points.

15. The method of claim 7, wherein the time domain RPI is broadcast in a master information block, MIB.

16. The method of claim 7, wherein the receiving comprises: receiving the broadcast message while the UE is in an idle mode.

17. The method of claim 1, wherein the indication of the time domain RPI comprises at least one of a dedicated message or a unicast message.

18. The method of claim 17, wherein the receiving comprises: receiving the at least one of the dedicated message or the unicast message while the UE is in a connected mode.

19. The method of claim 17, further comprising: determining, at the UE, a received power of a reference signal from the serving access point during the one or more protected subframes.

20. The method of claim 17, further comprising: at least one of determining channel state information, CSI, making radio resource management, RRM, measurements, or performing radio link monitoring, RLM, at the UE from one or more signals from the serving access point during the one or more protected subframes.

21. The method of claim 20, wherein the one or more protected subframes for RRM are the same as the protected subframes for RLM.

22. The method of claim 21, wherein a single information element IE is used to indicate the protected subframes for both RRM and RLM.

23. The method of claim 1, wherein the second IE comprises a cell identification, ID, of each of the at least one of the non-serving access points.

24. The method of claim 1, further comprising: determining, at the UE, at least one of Channel State Information (CSI), Radio Resource Management (RRM) measurements, or Radio Link Monitoring (RLM) based on one or more signals from the at least one of the non-serving access points during the second protected subframe.

25. The method of claim 1, wherein the one or more protected subframes are common to the serving access point and the one or more non-serving access points.

26. An apparatus for wireless communication, comprising:

a receiver configured to receive an indication of time domain resource partitioning information, RPI, corresponding to a subframe allocation between a serving access point and one or more non-serving access points in a heterogeneous network, wherein the indication of time domain RPI comprises:

a second information element, IE, for indicating a second protected subframe associated with at least one of the non-serving access points; or

The second IE and a first IE indicating a first protected subframe associated with the serving access point; and

at least one processor configured to identify one or more protected subframes from the time domain RPI, the one or more protected subframes being subframes that limit usage by an interfering access point.

27. The apparatus of claim 26, wherein the one or more protected subframes comprise Almost Blank Subframes (ABSs) associated with the interfering access point.

28. The apparatus of claim 26, wherein the time domain RPI comprises a bitmap with one or more bits set to a value indicating the one or more protected subframes.

29. The apparatus of claim 26, wherein the indication of the time domain RPI is received from the serving access point.

30. The apparatus of claim 26, wherein the interfering access point is one of the non-serving access points, and wherein the one or more protected subframes are associated with the serving access point.

31. The apparatus of claim 30, wherein the interfering access point is associated with a Closed Subscriber Group (CSG) to which the apparatus does not belong.

32. The apparatus of claim 26, wherein the indication of the time domain RPI is received in a broadcast message.

33. The apparatus of claim 32, wherein the time domain RPI in the broadcast message is associated with a first access point that is different from a second access point that transmitted the broadcast message, the first access point and the second access point being in the heterogeneous network.

34. The apparatus of claim 32, wherein the time domain RPI is broadcast in a system information block, SIB.

35. The apparatus of claim 34, wherein the receiver is configured to: receiving a neighbor list from the serving access point, wherein the neighbor list carries the time domain RPI in the SIB.

36. The apparatus of claim 32, wherein the receiver is configured to: receive the broadcast message from the serving access point including the time domain RPI corresponding to the serving access point, and wherein the at least one processor is to: identifying the one or more protected subframes by obtaining the one or more protected subframes for the one or more non-serving access points from the protected subframes for the serving access point.

37. The apparatus of claim 36, wherein the obtaining comprises: treat the one or more protected subframes for the one or more non-serving access points to be the same as the protected subframes for the serving access point.

38. The apparatus of claim 32, wherein the receiver is configured to: receiving the broadcast message from the one or more non-serving access points, the broadcast message including a time domain RPI related to the one or more protected subframes for the one or more non-serving access points.

39. The apparatus of claim 38, wherein the broadcast message comprises a system information block type 1(SIB1) from the one or more non-serving access points.

40. The apparatus of claim 32, wherein the time domain RPI is broadcast in a master information block, MIB.

41. The apparatus of claim 32, wherein the receiver is configured to: receiving the broadcast message while the apparatus is in an idle mode.

42. The apparatus of claim 26, wherein the indication of the time domain RPI comprises at least one of a dedicated message or a unicast message.

43. The apparatus of claim 42, wherein the receiver is configured to: receiving the at least one of the dedicated message or the unicast message while the apparatus is in a connected mode.

44. The apparatus of claim 42, wherein the at least one processor is configured to: determining a received power of a reference signal from the serving access point during the one or more protected subframes.

45. The apparatus of claim 42, wherein the at least one processor is configured to: determining at least one of channel state information, CSI, from one or more signals from the serving access point, making radio resource management, RRM, measurements, or performing radio link monitoring, RLM, during the one or more protected subframes.

46. The apparatus of claim 45, wherein the one or more protected subframes for RRM are the same as the protected subframes for RLM.

47. The apparatus of claim 46, wherein a single information element IE is used to indicate the protected subframes for both RRM and RLM.

48. The apparatus of claim 26, wherein the second IE comprises a cell identification, ID, of each of the at least one of the non-serving access points.

49. The apparatus of claim 26, wherein the at least one processor is configured to: determining at least one of channel state information, CSI, radio resource management, RRM, measurements, or radio link monitoring, RLM, from one or more signals from the at least one of the non-serving access points during the second protected subframe.

50. The apparatus of claim 26, wherein the one or more protected subframes are common to the serving access point and the one or more non-serving access points.

51. An apparatus for wireless communication, comprising:

means for receiving an indication of time domain resource partitioning information, RPI, corresponding to a subframe allocation between a serving access point and one or more non-serving access points in a heterogeneous network, wherein the indication of time domain RPI comprises:

a second information element, IE, for indicating a second protected subframe associated with at least one of the non-serving access points; or

The second IE and a first IE indicating a first protected subframe associated with the serving access point; and

means for identifying one or more protected subframes from the time domain RPI, the one or more protected subframes being subframes that limit usage by an interfering access point.

52. The apparatus of claim 51, wherein the one or more protected subframes comprise Almost Blank Subframes (ABS) associated with the interfering access point.

53. The apparatus of claim 51, wherein the time domain RPI comprises a bitmap with one or more bits set to a value indicating the one or more protected subframes.

54. The apparatus of claim 51, wherein the indication of the time domain RPI is received from the serving access point.

55. The apparatus of claim 51, wherein the interfering access point is one of the non-serving access points, and wherein the one or more protected subframes are associated with the serving access point.

56. The apparatus of claim 55, wherein the interfering access point is associated with a Closed Subscriber Group (CSG) to which the apparatus does not belong.

57. The apparatus of claim 51, wherein the indication of the time domain RPI is received in a broadcast message.

58. The apparatus of claim 57, wherein the time domain RPI in the broadcast message is associated with a first access point that is different from a second access point that transmitted the broadcast message, the first access point and the second access point being in the heterogeneous network.

59. The apparatus of claim 57, wherein the time domain RPI is broadcast in a System Information Block (SIB).

60. The apparatus of claim 59, wherein the means for receiving is further for: receiving a neighbor list from the serving access point, wherein the neighbor list carries the time domain RPI in the SIB.

61. The apparatus of claim 57, wherein the means for receiving is configured to: receive the broadcast message from the serving access point including the time domain RPI corresponding to the serving access point, and wherein the means for identifying is to: obtaining the one or more protected subframes for the one or more non-serving access points from the protected subframes for the serving access point.

62. The apparatus of claim 61, wherein the means for identifying is configured to: obtaining the one or more protected subframes by considering the one or more protected subframes for the one or more non-serving access points to be the same as the protected subframes for the serving access point.

63. The apparatus of claim 57, wherein the means for receiving is configured to: receiving the broadcast message from the one or more non-serving access points, the broadcast message including a time domain RPI related to the one or more protected subframes for the one or more non-serving access points.

64. The apparatus of claim 63, wherein the broadcast message comprises a system information block type 1(SIB1) from the one or more non-serving access points.

65. The apparatus of claim 57, wherein the time domain RPI is broadcast in a Master Information Block (MIB).

66. The apparatus of claim 57, wherein the means for receiving is configured to: receiving the broadcast message while the apparatus is in an idle mode.

67. The apparatus of claim 51, wherein the indication of the time domain RPI comprises at least one of a dedicated message or a unicast message.

68. The apparatus of claim 67, wherein the means for receiving is configured to: receiving the at least one of the dedicated message or the unicast message while the apparatus is in a connected mode.

69. The apparatus of claim 67, further comprising: means for determining a received power of a reference signal from the serving access point during the one or more protected subframes.

70. The apparatus of claim 67, further comprising: means for determining channel state information, CSI, from one or more signals from the serving access point during the one or more protected subframes, means for making radio resource management, RRM, measurements, or means for performing radio link monitoring, RLM.

71. The apparatus of claim 70, wherein the one or more protected subframes for RRM are the same as the protected subframes for RLM.

72. The apparatus of claim 71, wherein a single information element IE is used to indicate the protected subframes for both RRM and RLM.

73. The apparatus of claim 51, wherein the second IE comprises a cell Identification (ID) for each of the at least one of the non-serving access points.

74. The apparatus of claim 51, further comprising: means for determining channel state information, CSI, from one or more signals from the at least one of the non-serving access points, means for making radio resource management, RRM, measurements, or means for performing radio link monitoring, RLM, during the second protected subframe.

75. The apparatus of claim 51, wherein the one or more protected subframes are common to the serving access point and the one or more non-serving access points.

76. A method for wireless communication, comprising:

participating in time domain resource division in a heterogeneous network; and

transmitting, to a User Equipment (UE), an indication of time domain Resource Partitioning Information (RPI) corresponding to a subframe allocation between a serving access point and one or more non-serving access points in the heterogeneous network, the time domain RPI identifying one or more protected subframes that are subframes that limit usage of interfering access points, wherein the indication of time domain RPI comprises:

a second information element, IE, for indicating second protected subframes associated with the one or more non-serving access points; or

The second IE and a first IE indicating a first protected subframe associated with the serving access point in the heterogeneous network.

77. The method of claim 76, the one or more protected subframes comprising Almost Blank Subframes (ABSs) associated with the interfering access point.

78. The method of claim 76, wherein the time domain RPI comprises a bitmap with one or more bits set to a value indicating the one or more protected subframes.

79. The method of claim 76, wherein the transmitting comprises: broadcasting the indication of the time domain RPI.

80. The method of claim 79, wherein the indication of the time domain RPI is broadcast from an access point associated with the one or more protected subframes.

81. The method of claim 79, wherein the indication of the time domain RPI is broadcast from a first access point, and wherein the one or more protected subframes are associated with a second access point different from the first access point in the heterogeneous network.

82. The method of claim 79, wherein the time domain RPI is broadcast in a System Information Block (SIB).

83. The method of claim 82, wherein the time domain RPI is broadcast in one or more Information Elements (IEs) of the SIB.

84. The method of claim 79, wherein the time domain RPI is broadcast in a Master information Block, MIB.

85. The method of claim 76, wherein the indication of the time domain RPI is transmitted using at least one of a dedicated message or a unicast message.

86. The method of claim 85, wherein the indication of the time domain RPI is transmitted to a user equipment, UE, operating in a connected mode.

87. The method of claim 86, further comprising:

transmitting a reference signal; and

receiving, from the UE, an indication of a received power of the reference signal determined during the one or more protected subframes.

88. The method of claim 86, further comprising:

transmitting one or more signals; and

receiving, from the UE, an indication of Channel State Information (CSI) based on the one or more signals determined during the one or more protected subframes.

89. The method of claim 86, wherein the protected subframes are used by the UE for Radio Resource Management (RRM) or Radio Link Management (RLM) procedures.

90. The method of claim 89, wherein the one or more protected subframes for RRM are the same as the protected subframes for RLM.

91. The method of claim 86, further comprising:

receiving a report from the UE indicating radio conditions; and

determining the one or more protected subframes identified by the time domain RPI based on the report and the time domain resource partitioning.

92. The method of claim 91, wherein the radio conditions comprise information regarding proximity of the UE to one or more non-serving access points.

93. The method of claim 92, wherein the one or more protected subframes comprise subframes divided for the one or more non-serving access points.

94. The method of claim 92, wherein the one or more protected subframes comprise subframes divided for a serving access point.

95. The method of claim 76, wherein the subframes are commonly partitioned for a serving access point and one or more non-serving access points in the heterogeneous network.

96. The method of claim 76, wherein the serving access point transmits the indication of the time domain RPI.

97. The method of claim 76, wherein the one or more protected subframes are dependent on a Physical Cell Identity (PCI) of an access point being measured.

98. The method of claim 97, wherein the one or more protected subframes are configured for a range or set of PCIs.

99. The method of claim 98, wherein the range or set of PCIs corresponds to a power class of an access point.

100. The method of claim 98, wherein the range or set of PCIs corresponds to access permissions of access points.

101. An apparatus for wireless communication, comprising:

at least one processor configured to participate in time domain resource partitioning in a heterogeneous network; and

a transmitter configured to transmit, to a User Equipment (UE), an indication of time domain Resource Partitioning Information (RPI) corresponding to a subframe allocation between a serving access point and one or more non-serving access points in the heterogeneous network, the time domain RPI identifying one or more protected subframes that are subframes that limit usage by interfering access points, wherein the indication of time domain RPI comprises:

a second information IE indicating a second protected subframe associated with the one or more non-serving access points; or

The second IE and a first IE indicating a first protected subframe associated with the serving access point in the heterogeneous network.

102. The apparatus of claim 101, the one or more protected subframes comprise an Almost Blank Subframe (ABS) associated with the interfering access point.

103. The apparatus of claim 101, wherein the time domain RPI comprises a bitmap with one or more bits set to a value indicating the one or more protected subframes.

104. The apparatus of claim 101, wherein the transmitter is configured to broadcast the indication of the time domain RPI.

105. The apparatus of claim 104, wherein the apparatus is an access point associated with the one or more protected subframes.

106. The apparatus of claim 104, wherein the apparatus is a first access point, and wherein the one or more protected subframes are associated with a second access point that is different from the first access point in the heterogeneous network.

107. The apparatus of claim 104, wherein the time domain RPI is broadcast in a system information block, SIB.

108. The apparatus of claim 107, wherein the time domain RPI is broadcast in one or more information elements, IEs, of the SIB.

109. The apparatus of claim 104, wherein the time domain RPI is broadcast in a master information block, MIB.

110. The apparatus of claim 101, wherein the indication of the time domain RPI is transmitted using at least one of a dedicated message or a unicast message.

111. The apparatus of claim 110, wherein the indication of the time domain RPI is transmitted to a user equipment, UE, operating in a connected mode.

112. The apparatus of claim 111, further comprising a receiver, wherein the transmitter is configured to transmit a reference signal, and wherein the receiver is configured to receive an indication of a received power of the reference signal determined during the one or more protected subframes from the UE.

113. The apparatus of claim 111, further comprising a receiver, wherein the transmitter is configured to transmit one or more signals, and wherein the receiver is configured to receive an indication of Channel State Information (CSI) based on the one or more signals determined during the one or more protected subframes from the UE.

114. The apparatus of claim 111, wherein the protected subframes are used by the UE for Radio Resource Management (RRM) or Radio Link Management (RLM) procedures.

115. The apparatus of claim 114, wherein the one or more protected subframes for RRM are the same as the protected subframes for RLM.

116. The apparatus of claim 111, further comprising a receiver configured to receive a report from the UE indicating radio conditions, and wherein the at least one processor is configured to determine the one or more protected subframes identified by the time domain RPI based on the report and the time domain resource partitioning.

117. The apparatus of claim 116, wherein the radio conditions comprise information regarding proximity of the UE to one or more non-serving access points.

118. The apparatus of claim 117, wherein the one or more protected subframes comprise subframes divided for the one or more non-serving access points.

119. The apparatus of claim 117, wherein the one or more protected subframes comprise subframes divided for a serving access point.

120. The apparatus of claim 101, wherein the subframe is jointly partitioned for a serving access point and one or more non-serving access points in the heterogeneous network.

121. The apparatus of claim 101, wherein the apparatus is the serving access point.

122. The apparatus of claim 101, wherein the one or more protected subframes are dependent on a Physical Cell Identity (PCI) of an access point being measured.

123. The apparatus of claim 122, wherein the one or more protected subframes are configured for a range or a set of PCIs.

124. The apparatus of claim 123, wherein the range or set of PCIs corresponds to a power class of an access point.

125. The apparatus of claim 123, wherein the range or set of PCIs corresponds to access permissions of access points.

126. An apparatus for wireless communication, comprising:

means for participating in time domain resource partitioning in a heterogeneous network; and

means for transmitting an indication of time domain Resource Partitioning Information (RPI) to a User Equipment (UE), the time domain RPI corresponding to a subframe allocation between a serving access point and one or more non-serving access points in the heterogeneous network, the time domain RPI identifying one or more protected subframes that are subframes that limit usage by interfering access points, wherein the indication of time domain RPI comprises:

a second information IE indicating a second protected subframe associated with the one or more non-serving access points; or

The second IE and a first IE indicating a first protected subframe associated with the serving access point in the heterogeneous network.

127. The apparatus of claim 126, the one or more protected subframes comprise an Almost Blank Subframe (ABS) associated with the interfering access point.

128. The apparatus of claim 126, wherein the time domain RPI comprises a bitmap with one or more bits set to a value indicating the one or more protected subframes.

129. The apparatus of claim 126, wherein the means for transmitting is configured to broadcast the indication of the time domain RPI.

130. The apparatus of claim 129, wherein the apparatus is an access point associated with the one or more protected subframes.

131. The apparatus of claim 129, wherein the apparatus is a first access point, and wherein the one or more protected subframes are associated with a second access point different from the first access point in the heterogeneous network.

132. The apparatus of claim 129, wherein the time domain RPI is broadcast in a system information block, SIB.

133. The apparatus of claim 132, wherein the time domain RPI is broadcast in one or more information elements, IEs, of the SIB.

134. The apparatus of claim 129, wherein the time domain RPI is broadcast in a master information block, MIB.

135. The apparatus of claim 126, wherein the indication of the time domain RPI is transmitted using at least one of a dedicated message or a unicast message.

136. The apparatus of claim 135, wherein the indication of the time domain RPI is transmitted to a user equipment, UE, operating in a connected mode.

137. The apparatus of claim 136, further comprising means for receiving, wherein the means for transmitting is configured to transmit a reference signal, and wherein the means for receiving is configured to receive, from the UE, an indication of a received power of the reference signal determined during the one or more protected subframes.

138. The apparatus of claim 136, further comprising means for receiving, wherein the means for transmitting is configured to transmit one or more signals, and wherein the means for receiving is configured to receive, from the UE, an indication of channel state information, CSI, based on the one or more signals determined during the one or more protected subframes.

139. The apparatus of claim 136, wherein the protected subframes are used by the UE for Radio Resource Management (RRM) or Radio Link Management (RLM) procedures.

140. The apparatus of claim 139, wherein the one or more protected subframes for RRM are the same as the protected subframes for RLM.

141. The apparatus of claim 136, further comprising:

means for receiving a report from the UE indicating radio conditions; and

means for determining the one or more protected subframes identified by the time domain RPI based on the reporting and the time domain resource partitioning.

142. The apparatus of claim 141, wherein the radio conditions comprise information regarding proximity of the UE to one or more non-serving access points.

143. The apparatus of claim 142, wherein the one or more protected subframes comprise subframes divided for the one or more non-serving access points.

144. The apparatus of claim 142, wherein the one or more protected subframes comprise subframes divided for a serving access point.

145. The apparatus of claim 126, wherein the subframe is jointly partitioned for a serving access point and one or more non-serving access points in the heterogeneous network.

146. The apparatus of claim 126, wherein the apparatus is the serving access point.

147. The apparatus of claim 126, wherein the one or more protected subframes are dependent on a Physical Cell Identity (PCI) of an access point being measured.

148. The apparatus of claim 147, wherein the one or more protected subframes are configured for a range or a set of PCIs.

149. The apparatus of claim 148, wherein the range or set of PCIs corresponds to a power class of an access point.

150. The apparatus of claim 148, wherein the range or set of PCIs corresponds to access permissions of access points.