WO2017173621A1

WO2017173621A1 - Mitigation of ue-ue interference in flexible duplex mode

Info

Publication number: WO2017173621A1
Application number: PCT/CN2016/078674
Authority: WO
Inventors: Ruiming Zheng; Neng Wang; Peng Cheng
Original assignee: Qualcomm Incorporated
Priority date: 2016-04-07
Filing date: 2016-04-07
Publication date: 2017-10-12

Abstract

Aspects of the present disclosure provide a scheduling entity for communicating with a set of one or more subordinate entities utilizing frequency division duplexing on a downlink subcarrier and an uplink subcarrier. The scheduling entity further obtains interference measurement information indicating an interference power level within a cell associated with the scheduling entity, and based on at least the interference measurement information, enables a flexible duplex mode utilizing time division duplexing to dynamically switch between downlink transmissions on the uplink subcarrier and uplink transmissions on the uplink subcarrier.

Description

MITIGATION OF UE-UE INTERFERENCE IN FLEXIBLE DUPLEX MODE

TECHNICAL FIELD

Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to mitigating interference in a flexible duplex mode.

BACKGROUND

Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources.

The spectrum allocated to such wireless communication networks is typically apportioned between downlink transmissions from the base station to user equipment and uplink transmissions from the user equipment to the base station. Uplink and downlink transmissions in cellular systems typically operate in either a frequency division duplex (FDD) mode or a time division duplex (TDD) mode. In the FDD mode, the uplink and downlink transmissions are transmitted in different frequency bands, while in the TDD mode, the same frequency band is shared between uplink and downlink transmissions.

The TDD mode further provides the ability to flexibly adjust the available time domain resources to either downlink or uplink transmissions to match the uplink and downlink traffic characteristics in the network. For example, by changing the duplex switching point between uplink and downlink transmissions in the time domain, the available spectrum may be efficiently allocated based on the traffic conditions in the network.

The FDD mode may be enhanced by increasing the time-frequency resources assigned to downlink transmissions to accommodate the increasing demand for mobile broadband access. However, the FDD mode currently does not enable dynamic flexible allocation of time-frequency resources to manage the current traffic characteristics in the network.

BRIEF SUMMARY OF SOME EXAMPLES

The following presents a simplified summary of one or more aspects of the present disclosure, in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated features of the disclosure, and is intended neither to identify key or critical elements of all aspects of the disclosure nor to delineate the scope of any or all aspects of the disclosure. Its sole purpose is to present some concepts of one or more aspects of the disclosure in a simplified form as a prelude to the more detailed description that is presented later.

In an aspect of the disclosure, a method and scheduling entity apparatus are provided. The scheduling entity communicates with a set of one or more subordinate entities utilizing frequency division duplexing on a downlink subcarrier and an uplink subcarrier. The scheduling entity further obtains interference measurement information indicating an interference power level within a cell associated with the scheduling entity. Based on the interference measurement information, the scheduling entity further enables a flexible duplex mode utilizing time division duplexing to dynamically switch between downlink transmission on the uplink subcarrier and uplink transmissions on the uplink subcarrier. For example, the scheduling entity may compare the interference power level with an interference threshold, and if the interference power level is greater than the interference threshold, maintain communication between the scheduling entity and the set of one or more subordinate entities using frequency division duplexing on the uplink subcarrier. However, if the interference power level is less than or equal to the interference threshold, the scheduling entity may enable the flexible duplex mode.

These and other aspects of the invention will become more fully understood upon a review of the detailed description, which follows. Other aspects, features, and embodiments of the present invention will become apparent to those of ordinary skill in the art, upon reviewing the following description of specific, exemplary embodiments of the present invention in conjunction with the accompanying figures. While features of the present invention may be discussed relative to certain embodiments and figures below, all embodiments of the present invention can include one or more of the advantageous features discussed herein. In other words, while one or more embodiments may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various embodiments of the invention discussed herein. In similar fashion, while exemplary embodiments may be discussed below as device, system, or method embodiments it should be understood that such exemplary embodiments can be implemented in various devices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of an access network.

FIG. 2 is a block diagram conceptually illustrating an example of a scheduling entity communicating with one or more subordinate entities according to some embodiments.

FIG. 3 is a diagram illustrating an example of a downlink frame structure for use in an access network.

FIG. 4 is a diagram illustrating an example of an uplink frame structure for use in an access network.

FIGs. 5A and 5B are diagrams illustrating examples of frequency division duplexing and time division duplexing.

FIG. 6 is a diagram illustrating an example of a flexible duplex mode.

FIGs. 7A and 7B are diagrams illustrating examples of interference that may result in the flexible duplex mode.

FIG. 8 is a block diagram illustrating an example of a hardware implementation for a scheduling entity employing a processing system according to some embodiments.

FIG. 9 is a block diagram illustrating an example of a hardware implementation for a subordinate entity employing a processing system according to some embodiments.

FIG. 10 is a diagram illustrating an example of an interference power detection pattern for the flexible duplex mode on one or more subframes of an uplink subcarrier.

FIG. 11 is a flow chart of a method for enabling a flexible duplex mode in a wireless communication network.

FIG. 12 is a flow chart of a method for interference measurement before enabling the flexible duplex mode.

FIG. 13 is a flow chart of a method for implementing a flexible duplex mode in a wireless communication network.

FIG. 14 is a diagram illustrating an example of implementing the flexible duplex mode in accordance with the method of FIG. 13.

FIG. 15 is a flow chart of another method for implementing a flexible duplex mode in a wireless communication network.

FIG. 16 is a diagram illustrating an example of implementing the flexible duplex mode in accordance with the method of FIG. 15.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

The various concepts presented throughout this disclosure may be implemented across a broad variety of telecommunication systems, network architectures, and communication standards. Referring now to FIG. 1, as an illustrative example without limitation, a simplified schematic illustration of an access network 100 is provided.

The geographic region covered by the access network 100 may be divided into a number of cellular regions (cells) , including

macrocells

102, 104, and 106, and a small cell 108, each of which may include one or more sectors. Cells may be defined geographically (e.g., by coverage area) and/or may be defined in accordance with a frequency, scrambling code, etc. In a cell that is divided into sectors, the multiple sectors within a cell can be formed by groups of antennas with each antenna responsible for communication with mobile devices in a portion of the cell.

In general, a radio transceiver apparatus serves each cell. A radio transceiver apparatus is commonly referred to as a base station (BS) in many wireless communication systems, but may also be referred to by those skilled in the art as a base transceiver station (BTS) , a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , an access point (AP) , a Node B, an eNode B, or some other suitable terminology.

In FIG. 1, two high-

power base stations

110 and 112 are shown in

cells

102 and 104； and a third high-power base station 114 is shown controlling a remote radio head (RRH) 116 in cell 106. In this example, the

cells

102, 104, and 106 may be referred to as macrocells, as the high-

power base stations

110, 112, and 114 support cells having a large size. Further, a low-power base station 118 is shown in the small cell 108 (e.g., a microcell, picocell, femtocell, home base station, home Node B, home eNode B, etc. ) which may overlap with one or more macrocells. In this example, the cell 108 may be referred to as a small cell, as the low-power base station 118 supports a cell having a relatively small size. Cell sizing can be done according to system design as well as component constraints. It is to be understood that the access network 100 may include any number of wireless base stations and cells. The

base stations

110, 112, 114, 118 provide wireless access points to a core network for any number of mobile apparatuses.

FIG. 1 further includes a quadcopter or drone 120, which may be configured to function as a base station. That is, in some examples, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile base station such as the quadcopter 120.

In some examples, the base stations may be interconnected to one another and/or to one or more other base stations or network nodes (not shown) in the access network 100 through various types of backhaul interfaces such as a direct physical connection, a virtual network, or the like using any suitable transport network.

The access network 100 is illustrated supporting wireless communication for multiple mobile apparatuses. A mobile apparatus is commonly referred to as user equipment (UE) in standards and specifications promulgated by the 3rd Generation Partnership Project (3GPP) , but may also be referred to by those skilled in the art as a mobile station (MS) , a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal (AT) , a mobile terminal, a wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile client, a client, or some other suitable terminology.

Within the present document, a “mobile” apparatus need not necessarily have a capability to move, and may be stationary. Some non-limiting examples of a mobile apparatus include a mobile, a cellular (cell) phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal computer (PC) , a notebook, a netbook, a smartbook, a tablet, and a personal digital assistant (PDA) . A mobile apparatus may additionally be an “Internet of things” (IoT) device such as an automotive or other transportation vehicle, a satellite radio, a global positioning system (GPS) device, a logistics controller, a drone, a multi-copter, a quad-copter, a smart energy or security device, municipal lighting, water, or other infrastructure； industrial automation and enterprise devices； consumer and wearable devices, such as eyewear, a wearable camera, a smart watch, a health or fitness tracker, a digital audio player (e.g., MP3 player) , a camera, a game console, etc. ； and digital home or smart home devices such as a home audio, video, and multimedia device, an appliance, a sensor, a vending machine, intelligent lighting, a home security system, a smart meter, etc.

Within the access network 100, the cells may include UEs that may be in communication with one or more sectors of each cell. For example,

UEs

122 and 124 may be in communication with base station 110；

UEs

126 and 128 may be in communication with base station 112；

UEs

130 and 132 may be in communication with base station 114 by way of RRH 116； UE 134 may be in communication with low-power base station 118； and UE 136 may be in communication with mobile base station 120. Here, each

base station

110, 112, 114, 118, and 120 may be configured to provide an access point to a core network (not shown) for all the UEs in the respective cells.

In another example, the quadcopter 120 may be configured to function as a UE. For example, the quadcopter 120 may operate within cell 102 by communicating with base station 110.

The air interface in the access network 100 may utilize one or more multiplexing and multiple access algorithms to enable simultaneous communication of the various devices. For example, multiple access for uplink (UL) or reverse link transmissions from

UEs

122 and 124 to base station 110 may be provided utilizing time division multiple access (TDMA) , code division multiple access (CDMA) , frequency division multiple access (FDMA) , orthogonal frequency division multiple access (OFDMA) , or other suitable multiple access schemes. Further, multiplexing downlink (DL) or forward link transmissions from the base station 110 to UEs 122 and 124 may be provided utilizing time division multiplexing (TDM) , code division multiplexing (CDM) , frequency division multiplexing (FDM) , orthogonal frequency division multiplexing (OFDM) , or other suitable multiplexing schemes.

Within the access network 100, during a call with a scheduling entity, or at any other time, a UE may monitor various parameters of the signal from its serving cell as well as various parameters of neighboring cells. Further, depending on the quality of these parameters, the UE may maintain communication with one or more of the neighboring cells. During this time, if the UE moves from one cell to another, or if signal quality from a neighboring cell exceeds that from the serving cell for a given amount of time, the UE may undertake a handoff or handover from the serving cell to the neighboring (target) cell. For example, UE 124 may move from the geographic area corresponding to its serving cell 102 to the geographic area corresponding to a neighbor cell 106. When the signal strength or quality from the neighbor cell 106 exceeds that of its serving cell 102 for a given amount of time, the UE 124 may transmit a reporting message to its serving base station 110 indicating this condition. In response, the UE 124 may receive a handover command, and the UE may undergo a handover to the cell 106.

In some examples, access to the air interface may be scheduled, wherein a scheduling entity (e.g., a base station) allocates resources for communication among some or all devices and equipment within its service area or cell. Within the present disclosure, as discussed further below, the scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, subordinate entities utilize resources allocated by the scheduling entity.

Base stations are not the only entities that may function as a scheduling entity. That is, in some examples, a UE may function as a scheduling entity, scheduling resources for one or more subordinate entities (e.g., one or more other UEs) . For example, UE 138 is illustrated communicating with

UEs

140 and 142. In this example, the UE 138 is functioning as a scheduling entity, and

UEs

140 and 142 utilize resources scheduled by the UE 138 for wireless communication. A UE may function as a scheduling entity in a peer-to-peer (P2P) network, and/or in a mesh network. In a mesh network example,

UEs

140 and 142 may optionally communicate directly with one another in addition to communicating with the scheduling entity 138.

Thus, in a wireless communication network with a scheduled access to time–frequency resources and having a cellular configuration, a P2P configuration, and a mesh configuration, a scheduling entity and one or more subordinate entities may communicate utilizing the scheduled resources. Referring now to FIG. 2, a block diagram illustrates a scheduling entity 202 and a plurality of subordinate entities 204. Here, the scheduling entity 202 may correspond to the

base stations

110, 112, 114, and 118. In additional examples, the scheduling entity 202 may correspond to the UE 138, the quadcopter 120, or any other suitable node in the access network 100. Similarly, in various examples, the subordinate entity 204 may correspond to the

UE

122, 124, 126, 128, 130, 132, 134, 136, 138, 140, and 142, or any other suitable node in the access network 100.

As illustrated in FIG. 2, the scheduling entity 202 may broadcast data 206 to one or more subordinate entities 204 (the data may be referred to as downlink data) . In accordance with certain aspects of the present disclosure, the term downlink (DL) may refer to a point-to-multipoint transmission originating at the scheduling entity 202. Broadly, the scheduling entity 202 is a node or device responsible for scheduling traffic in a wireless communication network, including the downlink transmissions and, in some examples, uplink data 210 from one or more subordinate entities to the scheduling entity 202. Another way to describe the system may be to use the term broadcast channel multiplexing. In accordance with aspects of the present disclosure, the term uplink (UL) may refer to a point-to-point transmission originating at a subordinate entity 204. Broadly, the subordinate entity 204 is a node or device that receives scheduling control information, including but not limited to scheduling grants, synchronization or timing information, or other control information from another entity in the wireless communication network such as the scheduling entity 202.

The scheduling entity 202 may broadcast a control channel 208 to one or more subordinate entities 204. Uplink data 210 and/or downlink data 206 may be transmitted using a transmission time interval (TTI) . Here, a TTI may correspond to an encapsulated set or packet of information capable of being independently decoded. In various examples, TTIs may correspond to frames, subframes, resource blocks, time slots, or other suitable groupings of bits for transmission.

Furthermore, the subordinate entities 204 may transmit uplink control information 212 to the scheduling entity 202. Uplink control information may include a variety of packet types and categories, including pilots, reference signals, and information configured to enable or assist in decoding uplink data transmissions. In some examples, the control information 212 may include a scheduling request (SR) , i.e., request for the scheduling entity 202 to schedule uplink transmissions. Here, in response to the SR transmitted on the control channel 212, the scheduling entity 202 may transmit in the downlink control channel 208 information that may schedule the TTI for uplink packets. In a further example, the uplink control channel 212 may include hybrid automatic repeat request (HARQ) feedback transmissions, such as an acknowledgment (ACK) or negative acknowledgment (NACK) . HARQ is a technique well-known to those of ordinary skill in the art, wherein packet transmissions may be checked at the receiving side for accuracy, and if confirmed, an ACK may be transmitted, whereas if not confirmed, a NACK may be transmitted. In response to a NACK, the transmitting device may send a HARQ retransmission, which may implement chase combining, incremental redundancy, etc.

The channels illustrated in FIG. 2 are not necessarily all of the channels that may be utilized between a scheduling entity 202 and subordinate entities 204, and those of ordinary skill in the art will recognize that other channels may be utilized in addition to those illustrated, such as other data, control, and feedback channels.

Various frame structures may be used to support the DL and UL transmissions. An example of a DL frame structure will now be presented with reference to FIG. 3. However, as those skilled in the art will readily appreciate, the frame structure for any particular application may be different depending on any number of factors. In this example, a frame (10 ms) is divided into 10 equally sized subframes. Each subframe includes two consecutive time slots.

A resource grid may be used to represent two time slots, each time slot including a resource block. The resource grid is divided into multiple resource elements. For example, in LTE, a resource block contains 12 consecutive subcarriers in the frequency domain and, for a normal cyclic prefix in each OFDM symbol, 7 consecutive OFDM symbols in the time domain, or 84 resource elements. Some of the resource elements, as indicated as

R

302, 304, include DL reference signals (DL-RS) . The DL-RS include Cell-specific RS (CRS) (also sometimes called common RS) 302 and UE-specific RS (UE-RS) 304. UE-RS 304 are transmitted only on the resource blocks upon which the corresponding physical downlink shared channel (PDSCH) is mapped. The number of bits carried by each resource element depends on the modulation scheme. Thus, the more resource blocks that a subordinate entity receives and the higher the modulation scheme, the higher the data rate for the subordinate entity.

An example of a UL frame structure 400 will now be presented with reference to FIG. 4. The available resource blocks for the UL may be partitioned into a data section and a control section. The control section may be formed at the two edges of the system bandwidth and may have a configurable size. The resource blocks in the control section may be assigned to subordinate entities for transmission of control information. The data section may include all resource blocks not included in the control section. The structure shown in FIG. 4 results in the data section including contiguous subcarriers, which may allow a single subordinate entity to be assigned all of the contiguous subcarriers in the data section.

A subordinate entity may be assigned

resource blocks

410a, 410b in the control section to transmit control information to a scheduling entity. The subordinate entity may also be assigned

resource blocks

420a, 420b in the data section to transmit data to the scheduling entity. The subordinate entity may transmit control information in a physical uplink control channel (PUCCH) on the assigned resource blocks in the control section. The subordinate entity may transmit only data or both data and control information in a physical uplink shared channel (PUSCH) on the assigned resource blocks in the data section. A UL transmission may span both slots of a subframe and may hop across frequency as shown in FIG. 4.

As also shown in FIG. 4, a set of resource blocks may be used to perform initial system access and achieve UL synchronization in a physical random access channel (PRACH) 430. The PRACH 430 carries a random sequence and cannot carry any UL data/signaling. Each random access preamble occupies a bandwidth corresponding to six consecutive resource blocks. The starting frequency is specified by the network. That is, the transmission of the random access preamble is restricted to certain time and frequency resources. There is no frequency hopping for the PRACH. The PRACH attempt is carried in a single subframe (1 ms) and a UE can make only a single PRACH attempt per frame (10 ms) .

FIGs. 5A and 5B are diagrams illustrating examples of frequency division duplexing (FDD) and time division duplexing (TDD) . The FDD and TDD modes shown in FIGs. 5A and 5B may utilize any frame structure, such as the frame structures shown in FIGs. 3 and 4. As shown in FIG. 5A, in FDD, uplink (UL) transmissions 500 and downlink (DL) transmissions 510 are separated in the frequency domain, with a guard band separating the two frequency bands or channels used for the DL 500 and UL 510. As shown in FIG. 3B, in TDD, the UL transmissions 500 and DL transmissions 510 are separated in the time domain, with a guard period separating the UL/DL transmissions. Thus, with TDD, a single frequency band is used for both UL 500 and DL 510 transmissions, and may be shared, for example, by assigning alternating frames or subframes to UL 500 and DL 510 transmissions.

With the increase in demand for DL resources and the limited available spectrum, flexible resource allocation for traffic adaptation in both the FDD and TDD modes is desired. In FDD, the traffic ratio between DL and UL transmissions may be increased to 4: 1 or higher to accommodate mobile broadband Internet access and video data for mobile traffic. For example, DL throughput may be enhanced by 50％or more when 40％or more of the FDD UL subframes are used for DL data transmissions (in addition to the FDD DL subframes) . However, dynamic flexible allocation of time-frequency resources to the UL or DL based on current, real-time traffic conditions is not available in FDD mode.

By contrast, in TDD mode, the time domain resources may be flexibly allocated in real-time to either UL or DL by changing the duplex switching point between UL and DL in the time domain, thus moving capacity from the UL to the DL, or vice-versa. Referring now to FIG. 6, in accordance with aspects of the present disclosure, wireless communication networks utilizing FDD may provide the benefits of dynamic flexible allocation offered by TDD using a flexible duplex mode in which the UL frequency band may be reconfigured for TDD to accommodate the current traffic conditions in the network.

For example, as shown in FIG. 6, an access network 600 may include two cells 610, Cell A and Cell B, each served by a respective scheduling entity (eNB) 620. Each of the cells 610 may be configured to operate in FDD mode, by default. However, during periods of high DL traffic in a particular cell 610, such as Cell B, the scheduling entity 620 serving Cell B may reconfigure the UL frequency band in Cell B to operate in a flexible duplex mode to offload some of the DL traffic onto the UL frequency band. In the flexible duplex mode, one or more subcarriers in the frequency band assigned to the UL in FDD mode may switch from FDD to TDD for one or more frames or subframes. For example, as shown in FIG. 6, the scheduling entity 610 within Cell B may enable the flexible duplex mode for a particular frame, thus providing the ability to dynamically switch between DL transmissions and UL transmissions in the time domain (via subframes) over one or more subcarriers in the UL frequency band. In the example shown in FIG. 6, the UL frequency band of

subframes

0, 1, 3, 4, 5, 6, 7, 8, and 9 of a particular frame are dynamically allocated to DL transmissions, while subframe 2 continues to be allocated to UL transmissions.

The DL transmissions within

subframes

0, 1, 3, 4, 5, 6, 7, 8, and 9 in Cell B may cause interference with UL transmissions received at the scheduling entity 620 in Cell A.In addition, UL transmissions by a subordinate entity (UE) 630 in Cell A during

subframes

0, 1, 3, 4, 5, 6, 7, 8, and 9 may cause interference with the DL transmissions received by a subordinate entity (UE) 630 in Cell B. Depending on the distance between the subordinate entities 630 in Cell A and Cell B and the transmit power of the interfering subordinate entity 630 in Cell A, the UE-UE interference may significantly degrade the DL transmissions received by the subordinate entity 630 in Cell B.

FIGs. 7A and 7B are diagrams illustrating examples of interference that may result in the flexible duplex mode. In FIG. 7A, the signal power of an interfering UE as received at an interfered UE is plotted against the UE-UE distance for different transmit signal powers of the interfering UE. As seen in FIG. 7A, with different interfering UE transmit powers, the signal power received at the interfered UE is between about -60 dBm and -100 dBm for a UE-UE distance less than 10 meters. In FIG. 7B, the signal-to-interference-plus-noise ratio (SINR) degradation experienced by the interfered UE is plotted against the UE-UE distance for different transmit signal powers of the interfering UE. As seen in FIG. 7B, the interfering UE with 23 dBm full transmit power causes significant DL transmission SINR degradation to the interfered UE when the UE-UE distance is less than 4 meters. At lower transmit powers (e.g., 3 dBm) , the DL SINR degradation experienced by the interfered UE is minimal.

FIG. 8 is a conceptual diagram illustrating an example of a hardware implementation for a scheduling entity 202 employing a processing system 814. In accordance with various aspects of the disclosure, an element, or any portion of an element, or any combination of elements may be implemented with a processing system 814 that includes one or more processors 804.

In various aspects of the disclosure, the scheduling entity 202 may be any suitable radio transceiver apparatus, and in some examples, may be embodied by a base station (BS) , a base transceiver station (BTS) , a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , an access point (AP) , a Node B, an eNode B (eNB) , mesh node, relay, peer, or some other suitable terminology. Within the present document, a base station may be referred to as a scheduling entity, indicating that the base station provides scheduling information to one or more subordinate entities.

In other examples, the scheduling entity 202 may be embodied by a wireless user equipment (UE) . Examples of a UE include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a notebook, a netbook, a smartbook, a personal digital assistant (PDA) , a satellite radio, a global positioning system (GPS) device, a multimedia device, a video device, a digital audio player (e.g., MP3 player) , a camera, a game console, an entertainment device, a vehicle component, a wearable computing device (e.g., a smart watch, a health or fitness tracker, etc. ) , an appliance, a sensor, a vending machine, or any other similar functioning device. The UE may also be referred to by those skilled in the art as a mobile station (MS) , a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal (AT) , a mobile terminal, a wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile client, a client, or some other suitable terminology. Within the present document, a UE may be referred to either as a scheduling entity, or a subordinate entity. That is, in various aspects of the present disclosure, a wireless UE may operate as a scheduling entity providing scheduling information to one or more subordinate entities, or may operate as a subordinate entity, operating in accordance with scheduling information provided by a scheduling entity.

Examples of processors 804 include microprocessors, microcontrollers, digital signal processors (DSPs) , field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. That is, the processor 804, as utilized in the scheduling entity 202, may be used to implement any one or more of the processes described below.

In this example, the processing system 814 may be implemented with a bus architecture, represented generally by the bus 802. The bus 802 may include any number of interconnecting buses and bridges depending on the specific application of the processing system 814 and the overall design constraints. The bus 802 links together various circuits including one or more processors (represented generally by the processor 804) , a memory 805, and computer-readable media (represented generally by the computer-readable medium 806) . The bus 802 may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further. A bus interface 808 provides an interface between the bus 802 and a transceiver 810. The transceiver 810 provides a means for communicating with various other apparatus over a transmission medium. Depending upon the nature of the apparatus, a user interface 812 (e.g., keypad, display, touch screen, speaker, microphone, joystick) may also be provided.

The processor 804 is responsible for managing the bus 802 and general processing, including the execution of software stored on the computer-readable medium 806. The software, when executed by the processor 804, causes the processing system 814 to perform the various functions described below for any particular apparatus. The computer-readable medium 806 may also be used for storing data that is manipulated by the processor 804 when executing software.

In some aspects of the disclosure, the processor 804 may include resource assignment and subframe control circuitry 841, configured to generate, schedule, and modify a resource assignment or grant of time–frequency resources. For example, the resource assignment and subframe control circuitry 841 may generate one or more subframes, each including time–frequency resources assigned to carry data and/or control information to and/or from multiple subordinate entities. The resource assignment and subframe control circuitry 841 may further be configured to enable frequency division multiplexing and/or time division multiplexing for uplink and downlink transmissions. The resource assignment and subframe control circuitry 841 may operate in coordination with resource assignment and subframe control software 851.

The processor 804 may further include downlink (DL) data and control channel generation and transmission circuitry 842, configured to generate and transmit downlink data and control channels. The DL data and control channel generation and transmission circuitry 842 may operate in coordination with the resource assignment and subframe control circuitry 841 to schedule the DL data and/or control information and to place the DL data and/or control information onto a subcarrier, such as a time division duplex (TDD) subcarrier or a frequency division duplex (FDD) subcarrier, within one or more subframes generated by the resource assignment and subframe control circuitry 841 in accordance with the resources assigned to the DL data and/or control information. The DL data and control channel generation and transmission circuitry 842 may further operate in coordination with DL data and control channel generation and transmission software 852.

The processor 804 may further include uplink (UL) data and control channel reception and processing circuitry 843, configured to receive and process uplink control channels and uplink data channels received on a FDD subcarrier or a TDD subcarrier from one or more subordinate entities. In some examples, the UL data and control channel reception and processing circuitry 843 may be configured to receive scheduling requests from one or more subordinate entities, the scheduling requests being configured to request a grant of time–frequency resources for uplink user data transmissions. In other examples, the UL data and control channel reception and processing circuitry 843 may be configured to receive and process acknowledgement information (e.g., acknowledged/not acknowledged packets) from one or more subordinate entities. The UL data and control channel reception and processing circuitry 843 may operate in coordination with the resource assignment and subframe control circuitry 841 to schedule UL data transmissions, DL data transmissions and/or DL data retransmissions in accordance with the received UL control channel information. The UL data and control channel reception and processing circuitry 843 may further operate in coordination with UL data and control channel reception and processing software 853.

The processor 804 may further include interference measurement circuitry 844, configured for measuring the interference power level within the cell on the uplink subcarrier. In this example, the interference power level represents the total interference power level collectively produced by interfering subordinate entities served by other (neighboring) scheduling entities. For example, the interference measurement circuitry 844 may detect the total signal power on the uplink carrier and subtract the total received power from subordinate entities in the cell from the total signal power to determine the interference power level. As another example, the interference measurement circuitry 844 may measure the pure interference power level from other subordinate entities in other cells during subframes that uplink transmissions from subordinate entities within the cell are not scheduled. The interference measurement circuitry 844 may further operate in coordination with interference measurement software 854.

The processor 804 may further include flexible duplex mode configuration circuitry 845, configured for obtaining interference measurement information indicating an interference power level within a cell associated with the scheduling entity and enabling a flexible duplex mode based on at least the interference measurement information. The flexible duplex mode utilizes time division duplexing (TDD) to dynamically switch between downlink transmissions and uplink transmissions on an uplink subcarrier or a downlink subcarrier. For ease of understanding, the below discussion is concerned with dynamic switching of downlink and uplink transmissions on an uplink subcarrier using TDD. However, it should be understood that the below discussion could equally apply to dynamic switching of downlink and uplink transmissions on a downlink subcarrier using TDD.

In various aspects of the present disclosure, the flexible duplex mode configuration circuitry 845 operates in coordination with the resource assignment and subframe generation circuitry 841 to enable time division duplexing on the uplink subcarrier and schedule downlink transmissions (and, in some examples, uplink transmissions) on the uplink subcarrier. In addition, the flexible duplex mode configuration circuitry 845 operates in coordination with the DL data and control channel generation and transmission circuitry 842 to notify the subordinate entities of the change from FDD to TDD on the uplink subcarrier and to provide scheduling information indicating one or more subframes on the uplink subcarrier allocated to downlink transmissions. For example, L1 (PDCCH) or Radio Resource Control (RRC) signaling may be used to communicate the switch from FDD to TDD on the uplink subcarrier and to provide the scheduling information to the subordinate entities.

In some examples, the flexible duplex mode configuration circuitry 845 compares the interference power level with an interference threshold to determine whether to enable the flexible duplex mode. For example, if the interference power level is greater than the interference threshold, the flexible duplex mode configuration circuitry does not enable the flexible duplex mode. In this example, the flexible duplex mode configuration circuitry 845 communicates with the resource assignment and subframe generation circuitry 841 to maintain frequency division duplexing on the uplink subcarrier and schedule only uplink transmissions on the uplink subcarrier. However, if the interference power level is less than or equal to the interference threshold, the flexible duplex mode configuration circuitry 845 enables the flexible duplex mode to utilize time division duplexing on the uplink subcarrier and schedule downlink transmissions on the uplink subcarrier.

In one example, the flexible duplex mode configuration circuitry 845 obtains the interference measurement information from the interference measurement circuitry 844. The flexible duplex mode configuration circuitry 845 may operate with the resource assignment and subframe generation circuitry 841 to avoid scheduling any subordinate entities in one or more subframes on the uplink subcarrier to enable the interference measurement circuitry 844 to measure the pure interference power level from other subordinate entities in other cells during those subframes. The flexible duplex mode configuration circuitry 845 may establish a detecting timing pattern for periodic (predetermined) triggering of interference measurements and/or may trigger interference measurements aperiodically based on, for example, the traffic loading (downlink and/or uplink) in the cell, buffer status or other factors.

In other examples, the flexible duplex mode configuration circuitry 845 receives interference measurement reports from one or more subordinate entities (UEs) in the cell and determines the interference measurement information from the interference measurement reports. The interference measurement reports may include, for example, the measured total interference power level in the cell (e.g., the total interference power level on the uplink subcarrier as measured by the subordinate entities) or the measured interference power level on the uplink subcarrier of a particular interfering UE in a neighboring cell. From the interference measurement reports, the flexible duplex mode configuration circuitry 845 may determine the total interference power level in the cell (e.g., an average of the reported interference power levels in the cell or a highest reported interference power level) or a local interference power level of the particular interfering UE (e.g., an average or a highest reported interference power level of that particular interfering UE) .

The flexible duplex mode configuration circuitry 845 may further operate with the DL data and control channel generation and transmission circuitry 842 to generate and transmit a control message including interference detection information to the subordinate entities in the cell. In some examples, the interference detection information includes scheduling information that grants one or more subframes (e.g., 1 –20 subframes) for the subordinate entities to detect and measure the interference power level on the uplink subcarrier (e.g., the total interference power level in the cell or the local interference power level of a particular interfering UE) and to transmit respective interference measurement reports containing the measured interference power levels to the scheduling entity 202.

In one example, the flexible duplex mode configuration circuitry 845 establishes a detection timing pattern to periodically trigger interference detection by the subordinate entities, and transmits the control message including the scheduling information to the subordinate entities based on the detection timing pattern. For example, the flexible duplex mode configuration circuitry 845 may transmit the control message on a FDD downlink subcarrier or on a TDD uplink subcarrier at least one subframe prior to the measurement period. The use of a detection timing pattern provides semi-static measurement periods within the cell. In addition, the detection timing pattern may be exchanged with other scheduling entities in the network via the X2 interface to ensure uplink interference measurement periods within neighboring cells do not overlap.

In another example, the flexible duplex mode configuration circuitry 845 establishes one or more factors for triggering interference detection and transmits the control message including the scheduling information based on the factors. The factors may include, for example, the traffic loading in the cell, the buffer status of the scheduling entity, and/or any other suitable factor. As an example, the flexible duplex mode configuration circuitry 845 may compare the downlink traffic loading in the cell to a threshold, and if the downlink traffic loading exceeds the threshold, trigger interference detection. This type of factor-based interference detection provides aperiodic triggering within the cell.

In other examples, one or more subordinate entities may generate and transmit a flexible duplex request to the scheduling entity 202 to request enablement of the flexible duplex mode. The flexible duplex request may include an interference measurement report, or may trigger interference detection, thereby causing the flexible duplex mode configuration circuitry 845 to measure the interference power level or to transmit the control message including the scheduling information for measuring the interference to the subordinate entities.

The flexible duplex mode configuration circuitry 845 may decide whether to enable the flexible duplex mode based on not only the interference measurement information, but also on the number of received flexible duplex requests. In addition, the flexible duplex mode configuration circuitry 845 may further consider the traffic loading and buffer status when deciding whether to enable the flexible duplex mode. Thus, the flexible duplex mode configuration circuitry 845 may determine interference measurement information, a number of received flexible duplex requests, a buffer status within the cell, and a traffic loading condition within the cell, and enable the flexible duplex mode based on the interference measurement information and one or more of the number of received flexible duplex requests, the buffer status, or the traffic loading condition.

In the flexible duplex mode, the flexible duplex mode configuration circuitry 845 may further operate with the resource assignment and subframe generation circuitry 841 to determine at least one resource block (time-frequency resources) to transmit a downlink signal to the subordinate entities in the cell over the uplink subcarrier. In addition, the flexible duplex mode configuration circuitry 845 may further transmit scheduling pattern information to another scheduling entity, via the X2 interface, to avoid scheduling uplink transmissions from at least one other subordinate entity (interfering UE) in wireless communication with the other scheduling entity during the designated resource blocks to mitigate interference from the interfering UE (s) during the designated resource blocks. For example, the flexible duplex mode configuration circuitry 845 may indicate a scheduling pattern of resource blocks on which downlink transmissions will occur on the uplink subcarrier, and request that the other scheduling entity not schedule uplink transmissions from at least the interfering UE during those designated resource blocks.

In some examples, the respective positions of each of the UEs (flexible duplex UE and interfering UE) and/or the distance between the UE’s is used to determine whether to send the scheduling pattern information or to determine whether to avoid scheduling uplink transmissions from the interfering UE during the designated resource block. For example, if the distance between the UE’s is more than a minimum distance at which interference from the interfering UE does not significantly degrade the downlink transmission received by the flexible duplex UE, the flexible duplex mode configuration circuitry 845 may not transmit the scheduling pattern information or the other scheduling entity may schedule uplink transmissions from the interfering UE during the designated resource blocks. The positions of each the UE’s may be determined, for example, based on the path loss of the respective uplink transmissions sent by each of the UE’s to their respective scheduling entity or other measurement. The distance between the UE’s may be determined, for example, based on the positions of the UE’s or the path loss between the UE’s , which may be reported by the UE’s to their respective scheduling entities. For example, the flexible duplex UE may include the path loss or distance between the flexible duplex UE and at least one interfering UE within the interference measurement report sent to the scheduling entity.

The flexible duplex mode configuration circuitry 845 may also receive a scheduling pattern from another scheduling entity indicating at least one resource block granted to an interfering UE in wireless communication with the other scheduling entity. The flexible duplex mode configuration circuitry 845 may operate with the resource assignment and subframe generation circuitry 841 to avoid scheduling downlink transmissions to the flexible duplex UE (s) during the designated resource blocks. In some examples, the distance between the flexible duplex UE and the interfering UE may be used to determine whether to avoid scheduling downlink transmissions on the uplink subcarrier during the designated resource blocks. For example, if the distance between the flexible duplex UE and the interfering UE is less than the minimum distance, the flexible duplex mode configuration circuitry 845 may request the resource assignment and subframe generation circuitry 841 to not schedule downlink transmissions during the designated resource blocks. The flexible duplex mode configuration circuitry 845 may operate in coordination with flexible duplex mode configuration software 855.

One or more processors 804 in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. The software may reside on a computer-readable medium 806. The computer-readable medium 806 may be a non-transitory computer-readable medium. A non-transitory computer-readable medium includes, by way of example, a magnetic storage device (e.g., hard disk, floppy disk, magnetic strip) , an optical disk (e.g., a compact disc (CD) or a digital versatile disc (DVD) ) , a smart card, a flash memory device (e.g., a card, a stick, or a key drive) , a random access memory (RAM) , a read only memory (ROM) , a programmable ROM (PROM) , an erasable PROM (EPROM) , an electrically erasable PROM (EEPROM) , a register, a removable disk, and any other suitable medium for storing software and/or instructions that may be accessed and read by a computer. The computer-readable medium may also include, by way of example, a carrier wave, a transmission line, and any other suitable medium for transmitting software and/or instructions that may be accessed and read by a computer. The computer-readable medium 806 may reside in the processing system 814, external to the processing system 814, or distributed across multiple entities including the processing system 814. The computer-readable medium 806 may be embodied in a computer program product. By way of example, a computer program product may include a computer-readable medium in packaging materials. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system.

FIG. 9 is a conceptual diagram illustrating an example of a hardware implementation for an exemplary subordinate entity 204 employing a processing system 914. In accordance with various aspects of the disclosure, an element, or any portion of an element, or any combination of elements may be implemented with a processing system 914 that includes one or more processors 904.

The processing system 914 may be substantially the same as the processing system 814 illustrated in FIG. 8, including a bus interface 908, a bus 902, memory 905, a processor 904, and a computer-readable medium 906. Furthermore, the subordinate entity 204 may include a user interface 912 and a transceiver 910 substantially similar to those described above in FIG. 8. The processor 904, as utilized in a subordinate entity 204, may be used to implement any one or more of the processes described below.

In some aspects of the disclosure, the processor 904 may include uplink (UL) data and control channel generation and transmission circuitry 942, configured to generate and transmit uplink data on an UL data channel, and to generate and transmit uplink control/feedback/acknowledgement information on an UL control channel. The UL data and control channel generation and transmission circuitry 942 may operate in coordination with UL data and control channel generation and transmission software 952. The processor 904 may further include downlink (DL) data and control channel reception and processing circuitry 944, configured for receiving and processing downlink data on a data channel, and to receive and process control information on one or more downlink control channels. In an aspect, the control information may include distributed unscheduled assistance information 915. In some examples, received downlink data and/or control information, such as distributed unscheduled assistance information 915, may be stored within memory 905. The DL data and control channel reception and processing circuitry 944 may operate in coordination with DL data and control channel reception and processing software 954.

The processor 904 may further include interference measurement circuitry 946, configured for measuring the interference within the cell or of a particular interfering subordinate entity in a neighboring cell on the uplink subcarrier. The interference measurement circuitry 946 may operate in coordination with interference measurement software 956.

The processor 904 may further include flexible duplex mode configuration circuitry 948, configured for enabling the flexible duplex mode to utilize time division duplexing to dynamically switch between downlink and uplink transmissions on an uplink subcarrier. In some examples, the flexible duplex mode configuration circuitry 948 may receive a control message from the scheduling entity to initiate measurement of the interference power level within the cell or the interference power level of a particular interfering subordinate entity (UE) served by another scheduling entity. The control message may include, for example, including interference detection information providing scheduling information granting one or more subframes (e.g., 1 –20 subframes) to detect and measure the interference power level on the uplink subcarrier (e.g., the total interference power level in the cell or the local interference power level of a particular interfering UE) and to transmit an interference measurement report containing the measured interference power level to the scheduling entity. In some examples, the interference measurement report may further include the path loss or distance between the subordinate entity and at least one interfering UE in another cell. The flexible duplex mode configuration circuitry 948 operates with the interference measurement circuitry 946 to measure the interference power level and generate the interference measurement report.

In other examples, the flexible duplex mode configuration circuitry 948 may initiate measurement of the interference power level via the interference measurement circuitry 946 without receiving the control message from the scheduling entity. In this example, the flexible duplex mode configuration circuitry 948 may include the measured interference power level with a flexible duplex request that requests the scheduling entity to enable the flexible duplex mode. The flexible duplex request may be generated, for example, based on a requested downlink bandwidth. The requested downlink bandwidth may be determined, for example, based on the amount and/or type of data currently being downloaded by the subordinate entity 204. The flexible duplex mode configuration circuitry 948 may further operate in coordination with flexible duplex mode configuration software 958.

One or more processors 904 in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. The software may reside on a computer-readable medium 906. The computer-readable medium 906 may be a non-transitory computer-readable medium. A non-transitory computer-readable medium includes, by way of example, a magnetic storage device (e.g., hard disk, floppy disk, magnetic strip) , an optical disk (e.g., a compact disc (CD) or a digital versatile disc (DVD) ) , a smart card, a flash memory device (e.g., a card, a stick, or a key drive) , a random access memory (RAM) , a read only memory (ROM) , a programmable ROM (PROM) , an erasable PROM (EPROM) , an electrically erasable PROM (EEPROM) , a register, a removable disk, and any other suitable medium for storing software and/or instructions that may be accessed and read by a computer. The computer-readable medium may also include, by way of example, a carrier wave, a transmission line, and any other suitable medium for transmitting software and/or instructions that may be accessed and read by a computer. The computer-readable medium 906 may reside in the processing system 914, external to the processing system 914, or distributed across multiple entities including the processing system 914. The computer-readable medium 406 may be embodied in a computer program product. By way of example, a computer program product may include a computer-readable medium in packaging materials. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system.

FIG. 10 is a diagram illustrating an example of an interference power detection pattern for the flexible duplex mode on one or more subframes of an uplink subcarrier 1000. In this example, the uplink subcarrier 1000 is used to transmit a number of frames 1010, and each frame (10 ms) is divided into 10 equally sized subframes 1020. The first frame utilizes frequency division duplexing (FDD) on the uplink subcarrier for uplink transmissions (U) on the subframes. The second frame utilizes time division duplexing (TDD) on the uplink subcarrier to dynamically switch between downlink transmissions (D) and uplink transmissions (U) on the uplink subcarrier. The third frame again utilizes FDD on the uplink subcarrier for uplink transmissions (U) , while the fourth frame utilizes TDD on the uplink subcarrier for uplink transmissions (U) and downlink transmissions (D) .

One or more of the subframes (D) may further be allocated as measurement subframes during which the subordinate entities measure the pure interference power level in the cell or from a particular interfering UE. In addition, the subordinate entities may further measure the interference power level within other downlink or uplink subframes over a period of one or more subframes or frames. The reported interference measurement information may then be used to determine whether to enable the flexible duplex mode for a fifth frame (not shown) .

FIG. 11 is a flow chart 1100 of a method for enabling a flexible duplex mode in a wireless communication network. The method may be performed by a scheduling entity 202 or subordinate entity 204 as described above and illustrated in FIGs. 8 and 9, by a processor or processing system, or by any suitable means for carrying out the described functions.

At block 1102, the scheduling entity and a set of one or more subordinate entities communicate utilizing frequency division duplexing on a downlink subcarrier and an uplink subcarrier. At block 1104, interference measurement information is obtained that indicates an interference power level within a cell associated with the scheduling entity. In one example, the interference power level represents the total interference power level on the uplink subcarrier within the cell. The total interference power level may include, for example, the aggregated interference power levels of all of the interfering subordinate entities in neighboring cells. The total interference power level may be measured by the scheduling entity or by one or more subordinate entities. In the latter example, the scheduling entity may average or take the highest interference power level measured by the subordinate entities as the total interference power within the cell. In another example, the interference power level represents the local interference power level of a particular interfering subordinate entity in another cell. The local interference power level may be the interference power level experienced by one subordinate entity in the cell or may be an average of the interference power levels experienced by two or more subordinate entities in the cell.

At block 1106, the flexible duplex mode is enabled based on at least the interference measurement information. In the flexible duplex mode, time division duplexing is utilized on the uplink subcarrier to dynamically switch between downlink transmissions and uplink transmissions on the uplink subcarrier. The flexible duplex mode may be enabled for one or more subframes or one or more frames, depending on, for example, the traffic loading in the cell, the buffer status of the scheduling entity, scheduling requests received from subordinate entities, and other factors.

FIG. 12 is a flow chart 1200 of a method for interference measurement before enabling the flexible duplex mode. The method may be performed by a scheduling entity 202 as described above and illustrated in FIG. 8, by a processor or processing system, or by any suitable means for carrying out the described functions.

At block 1202, the scheduling entity determines that an interference measurement is needed prior to enabling the flexible duplex mode. The interference measurements may be performed, for example, by the scheduling entity or one or more subordinate entities served by the scheduling entity. If the scheduling entity determines that the interference measurements should be performed by one or more subordinate entities, at block 1204, the scheduling entity instructs the subordinate entities to measure the interference power level within the cell. If the scheduling entity determines that the interference measurements should be performed at the scheduling entity, at block 1206, the scheduling entity measures the interference power level within the cell.

FIG. 13 is a flow chart 1300 of a method for implementing a flexible duplex mode in a wireless communication network. The method may be performed by a scheduling entity 202 as described above and illustrated in FIG. 8, by a processor or processing system, or by any suitable means for carrying out the described functions. FIG. 13 will be described with reference to the diagram shown in FIG. 14.

At block 1302, an aggressor scheduling entity 1402 (e.g., a normal scheduling entity that schedules uplink transmissions on the uplink subcarrier) schedules uplink transmissions by an interfering subordinate entity 1404 on the uplink subcarrier over one or more resource blocks (RBs) . At block 1304, the aggressor scheduling entity 1402 indicates the scheduled RBs and the interfering UE position to surrounding flexible duplex scheduling entities 1406, for example, via the X2 interface. At block 1306, if the interfering UE position is close enough to a UE 1408 served by a flexible duplex scheduling entity, the flexible duplex scheduling entity 1406 may not schedule downlink transmissions on the uplink subcarrier over the indicated RBs.

FIG. 15 is a flow chart 1500 of another method for implementing a flexible duplex mode in a wireless communication network. The method may be performed by a scheduling entity 202 as described above and illustrated in FIG. 8, by a processor or processing system, or by any suitable means for carrying out the described functions. FIG. 15 will be described with reference to the diagram shown in FIG. 16.

At block 1502, a flexible duplex scheduling entity 1406 schedules downlink transmissions on the uplink carrier over one or more resource blocks (RBs) . At block 1504, the flexible duplex scheduling entity 1406 indicates the scheduled RBs and the position of a flexible duplex UE 1408 served by the flexible duplex scheduling entity to surrounding normal scheduling entities 1402, for example, via the X2 interface. At block 1506, if the position of the flexible duplex UE 1408 is close enough to another UE (normal UE) 1404 served by the normal scheduling entity 1402, the normal scheduling entity may not schedule uplink transmissions by the normal UE on the uplink subcarrier over the indicated RBs.

As those skilled in the art will readily appreciate, various aspects described throughout this disclosure may be extended to any suitable telecommunication system, network architecture, and communication standard. By way of example, various aspects may be applied to UMTS systems such as W-CDMA, TD-SCDMA, and TD-CDMA. Various aspects may also be applied to systems employing Long Term Evolution (LTE) (in FDD, TDD, or both modes) , LTE-Advanced (LTE-A) (in FDD, TDD, or both modes) , CDMA2000, Evolution-Data Optimized (EV-DO) , Ultra Mobile Broadband (UMB) , IEEE 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Ultra-Wideband (UWB) , Bluetooth, and/or other suitable systems, including those described by yet-to-be defined wide area network standards. The actual telecommunication standard, network architecture, and/or communication standard employed will depend on the specific application and the overall design constraints imposed on the system.

Within the present disclosure, the word “exemplary” is used to mean “serving as an example, instance, or illustration. ” Any implementation or aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects of the disclosure. Likewise, the term “aspect” or “aspects” does not require that all aspects of the disclosure include the discussed feature, advantage or mode of operation. The term “coupled” is used herein to refer to the direct or indirect coupling between two objects. For example, if object A physically touches object B, and object B touches object C, then objects A and C may still be considered coupled to one another—even if they do not directly physically touch each other. For instance, a first die may be coupled to a second die in a package even though the first die is never directly physically in contact with the second die. The terms “circuit” and “circuitry” are used broadly, and intended to include both hardware implementations of electrical devices and conductors that, when connected and configured, enable the performance of the functions described in the present disclosure, without limitation as to the type of electronic circuits, as well as software implementations of information and instructions that, when executed by a processor, enable the performance of the functions described in the present disclosure.

One or more of the components, steps, features and/or functions illustrated in FIGs. 1–11 may be rearranged and/or combined into a single component, step, feature or function or embodied in several components, steps, or functions. Additional elements, components, steps, and/or functions may also be added without departing from novel features disclosed herein. The apparatus, devices, and/or components illustrated in FIGs. 1–11 may be configured to perform one or more of the methods, features, or steps described herein. The novel algorithms described herein may also be efficiently implemented in software and/or embedded in hardware.

It is to be understood that the specific order or hierarchy of steps in the methods disclosed is an illustration of exemplary processes. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the methods may be rearranged. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented unless specifically recited therein.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more. ” Unless specifically stated otherwise, the term “some” refers to one or more. A phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a； b； c； a and b； a and c； b and c； and a, b and c. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112 (f) , unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for. ”

Claims

A method of wireless communication between a scheduling entity and a set of one or more subordinate entities in a wireless communication network, the method comprising:

communicating between the scheduling entity and the set of one or more subordinate entities utilizing frequency division duplexing on a downlink subcarrier and an uplink subcarrier；

obtaining interference measurement information indicating an interference power level within a cell associated with the scheduling entity； and

based on at least the interference measurement information, enabling a flexible duplex mode utilizing time division duplexing to dynamically switch between downlink transmissions on the uplink subcarrier and uplink transmissions on the uplink subcarrier.
The method of claim 1, further comprising:

comparing the interference power level with an interference threshold；

if the interference power level is greater than the interference threshold, maintaining communication between the scheduling entity and the set of one or more subordinate entities using frequency division duplexing on the uplink subcarrier； and

if the interference power level is less than or equal to the interference threshold, enabling the flexible duplex mode.
The method of claim 1, wherein obtaining the interference measurement information indicating the interference power level within the cell further comprises:

receiving, at the scheduling entity, respective interference measurement reports containing respective interference measurement information from the set of one or more subordinate entities； and

determining the interference power level from the respective interference measurement reports.
The method of claim 3, wherein the interference power level comprises a total interference power level within the cell or a local interference power level of an interfering subordinate entity in wireless communication with another scheduling entity.
The method of claim 3, further comprising:

transmitting a control message to the set of one or more subordinate entities including interference detection information for use by the set of one or more subordinate entities in detecting the respective interference measurement information.
The method of claim 5, wherein the interference detection information comprises scheduling information that grants one or more subframes for the set of one or more subordinate entities to detect the respective interference measurement information and transmit the respective interference measurement reports to the scheduling entity.
The method of claim 6, wherein transmitting the control message to the set of one or more subordinate entities further comprises:

establishing a detection timing pattern to periodically trigger interference detection by the set of one or more subordinate entities； and

transmitting the control message including the scheduling information based on the detection timing pattern.
The method of claim 6, wherein transmitting the control message to the set of one or more subordinate entities further comprises:

establishing one or more factors for triggering interference detection by the set of one or more subordinate entities； and

transmitting the control message including the scheduling information based on the one or more factors.
The method of claim 1, further comprising:

receiving a flexible duplex request from at least one subordinate entity in the set of one or more subordinate entities, and wherein enabling the flexible duplex mode further comprises:

enabling the flexible duplex mode based on the flexible duplex request and the interference measurement information.
The method of claim 1, further comprising:

determining a buffer status and a traffic loading condition within the cell, and wherein enabling the flexible duplex mode further comprises:

enabling the flexible duplex mode based on the buffer status, the traffic loading condition and the interference measurement information.
The method of claim 1, wherein the obtaining the interference measurement information indicating the interference power level within the cell further comprises:

measuring, by the scheduling entity, the interference power level within the cell.
The method of claim 1, further comprising:

in the flexible duplex mode:

determining a resource block for transmitting a downlink signal from the scheduling entity to the set of subordinate entities over the uplink subcarrier； and

transmitting scheduling pattern information to another scheduling entity to avoid scheduling uplink transmissions from another subordinate entity in wireless communication with the other scheduling entity during the resource block to mitigate interference from the other subordinate entity during the resource block.
The method of claim 1, further comprising:

in the flexible duplex mode:

receiving a scheduling pattern from another scheduling entity indicating at least one resource block granted to an interfering subordinate entity in wireless communication with the other scheduling entity； and

avoiding scheduling downlink transmissions to the set of subordinate entities during the at least one resource block.
A scheduling entity in a wireless communication network, comprising:

a transceiver for wireless communication with a set of subordinate entities；

a memory； and

a processor communicatively coupled to the transceiver and the memory, the processor configured to:

communicate between the scheduling entity and the set of one or more subordinate entities utilizing frequency division duplexing on a downlink subcarrier and an uplink subcarrier；

obtain interference measurement information indicating an interference power level within a cell associated with the scheduling entity； and

based on at least the interference measurement information, enable a flexible duplex mode utilizing time division duplexing to dynamically switch between downlink transmissions on the uplink subcarrier and uplink transmissions on the uplink subcarrier.
The scheduling entity of claim 14, wherein the processor is further configured to:

compare the interference power level with an interference threshold；

if the interference power level is greater than the interference threshold, maintain communication between the scheduling entity and the set of one or more subordinate entities using frequency division duplexing on the uplink subcarrier； and

if the interference power level is less than or equal to the interference threshold, enable the flexible duplex mode.
The scheduling entity of claim 14, wherein the processor is further configured to:

receive respective interference measurement reports containing respective interference measurement information from the set of one or more subordinate entities； and

determine the interference power level from the respective interference measurement reports.
The scheduling entity of claim 16, wherein the processor is further configured to:

transmit, via the transceiver, a control message to the set of one or more subordinate entities including interference detection information for use by the set of one or more subordinate entities in detecting the respective interference measurement information.
A scheduling entity apparatus in a wireless communication network, comprising:

means for communicating between the scheduling entity and the set of one or more subordinate entities utilizing frequency division duplexing on a downlink subcarrier and an uplink subcarrier；

means for obtaining interference measurement information indicating an interference power level within a cell associated with the scheduling entity； and

based on at least the interference measurement information, means for enabling a flexible duplex mode utilizing time division duplexing to dynamically switch between downlink transmissions on the uplink subcarrier and uplink transmissions on the uplink subcarrier.
The scheduling entity apparatus of claim 18, further comprising:

means for comparing the interference power level with an interference threshold；

if the interference power level is greater than the interference threshold, means for maintaining communication between the scheduling entity and the set of one or more subordinate entities using frequency division duplexing on the uplink subcarrier； and

if the interference power level is less than or equal to the interference threshold, means for enabling the flexible duplex mode.
The scheduling entity apparatus of claim 18, further comprising:

means for receiving respective interference measurement reports containing respective interference measurement information from the set of one or more subordinate entities； and

means for determining the interference power level from the respective interference measurement reports.