WO2018209590A1

WO2018209590A1 - Extended gap for power saving and gsm measurement

Info

Publication number: WO2018209590A1
Application number: PCT/CN2017/084698
Authority: WO
Inventors: Tao Huang; Hao Sun; Yanxia Wang; Ying Zhang
Original assignee: Apple Inc.
Priority date: 2017-05-17
Filing date: 2017-05-17
Publication date: 2018-11-22

Abstract

Embodiments herein relate to a user equipment device (UE) and associated methods for performing time-division (TD) multiplexing communications. The UE may determine that one or more downlink and/or uplink subframes are potential non-scheduled subframes. The UE may reallocate resources to the determined one or more downlink and/or uplink subframes. The reallocation of resources may comprise powering off a transmitter or receiver of the UE during the determined one or more downlink and/or uplink subframes. The reallocation of resources may also comprise extending a measurement gap to include the determined one or more downlink and/or uplink subframes.

Description

EXTENDED GAP FOR POWER SAVING AND GSM MEASUREMENT

FIELD OF THE INVENTION

The present application relates to wireless devices, and more particularly to a system and method for providing improved performance and/or reduced power consumption in wireless devices that support measurement gaps in time-division multiplexing.

DESCRIPTION OF THE RELATED ART

Wireless communication systems are rapidly growing in usage. Further, wireless communication technology has evolved from voice-only communications to also include the transmission of data, such as Internet and multimedia content. Many wireless communication technologies, such as cellular communication technologies, are substantially designed to provide mobile communication capabilities to wireless devices, such as cellular phones. Users of such wireless devices may be able to move freely within a service territory of their service provider while using their wireless devices, and the wireless devices may operate in conjunction with the service provider’s network in a manner that accounts for such movement.

For example, if a cellular phone is experiencing degraded signal strength or quality, a common cause is movement of the cell phone (e.g., a user of the cell phone may be carrying the cell phone while moving) which results in lower signal strength or quality from the serving cell as the user moves away from the serving cell’s base station. As a result, some wireless communication technologies require that a wireless device search for alternative cells under certain conditions (e.g., detecting degraded signal strength or quality of the serving cell) and/or according to certain timelines. During these searches, the wireless device may enter a measurement gap wherein the wireless device temporarily halts communications with the serving cell’s base station.

However, performing such searches generally does consume power and decrease the battery life of the wireless device. As such, determining how such procedures should be performed under various circumstances, in light of device performance concerns and concerns regarding power consumption and battery life of the wireless device, is a difficult problem. Accordingly, improvements in wireless communication systems, may be desirable.

SUMMARY OF THE INVENTION

This document describes, inter alia, methods for entering an optimization mode for potential non-scheduled subframes in a time-division multiplexing communication system, and describes wireless devices configured to implement the described methods.

In some embodiments, a user equipment device (UE) may determine that one or more downlink (DL) subframes are scheduled for an acknowledgement feedback message (e.g., which may be a positive acknowledgement (ACK) or a negative acknowledgement (NACK) ) during an upcoming UL subframe that occurs within a measurement gap. The UE may designate these DL subframes as potential non-scheduled subframes, and may enter a mode (e.g., an optimization mode) where resources may be reallocated for or during these DL subframes. In some embodiments, the reallocation of resources may comprise powering off a receiver of the UE. In some embodiments, the reallocation of resources may comprise extending the measurement gap to include the DL subframes.

In some embodiments, a user equipment device (UE) may determine that one or more uplink (UL) subframes are potential non-scheduled subframes. In some embodiments, this determination may be based on the UL subframes being scheduled to transmit an ACK/NACK feedback message for previous DL subframes that occur within a measurement gap. Similar to above, the UE may enter a mode (e.g., an optimization mode) where resources are reallocated for or during these UL subframes. In some embodiments, the reallocation of resources may comprise powering off a transmitter of the UE. In some embodiments, the reallocation of resources may comprise extending the measurement gap to include the UL subframes.

Thus, it may be desirable to provide a way for a wireless device to more effectively utilize resources in communication sessions involving a measurement gap. Accordingly, embodiments are presented herein of such a method for a wireless user equipment (UE) device to determine potential non-scheduled subframes and reallocate or otherwise modify operation during those non-scheduled subframes, and a UE configured to implement the method.

The UE may include one or more radios, including one or more antennas, for performing wireless communications with base stations (BSs) . The UE may also include device logic (which may include a processor and memory medium and/or hardware logic) configured to implement the method. Embodiments are also presented of a memory medium (e.g., a non-transitory computer accessible memory medium) storing program instructions executable by a processor to perform part or all of the method.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present subject matter can be obtained when the following detailed description of the embodiments is considered in conjunction with the following drawings, in which:

Figure 1 illustrates an exemplary (and simplified) wireless communication system, according to some embodiments；

Figure 2 illustrates a base station (BS) in communication with a user equipment (UE) device, according to some embodiments；

Figure 3 illustrates an exemplary block diagram of a UE, according to some embodiments, according to some embodiments；

Figure 4 illustrates an exemplary block diagram of a BS, according to some embodiments, according to some embodiments；

Figure 5 is an illustration of a particular subframe configuration with a measurement gap, according to some embodiments；

Figure 6 is an illustration of a particular subframe configuration and associated potential non-scheduled subframes, according to some embodiments；

Figure 7 is an illustration of sets of potential non-scheduled subframes for a variety of different UL/DL configurations and gap offsets, according to some embodiments；

Figure 8 is an illustration of a downlink subframe scheduled for detection of a physical hybrid-ARQ indicator channel (PHICH) message； according to some embodiments；

Figure 9 is a flow chart diagram illustrating an exemplary method by which resources may be reallocated for DL subframes, according to some embodiments；

Figure 10 is a flow chart diagram illustrating an exemplary method by which resources may be reallocated for UL subframes, according to some embodiments； and

Figure 11 is an illustration of subframe allocation for an instance wherein it may be desirable for a UE to exit optimization mode, according to some embodiments.

While the features described herein may be susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to be limiting to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the subject matter as defined by the appended claims.

DETAILED DESCRIPTION

Acronyms

The following acronyms are used in this disclosure:

UE: User Equipment

BS: Base Station

GSM: Global System for Mobile Communication

UMTS: Universal Mobile Telecommunication System

LTE: Long Term Evolution

Terms

The following is a glossary of terms used in this disclosure:

Memory Medium –Any of various types of memory devices or storage devices. The term “memory medium” is intended to include an installation medium, e.g., a CD-ROM, floppy disks, or tape device； a computer system memory or random access memory such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc. ； a non-volatile memory such as a Flash, magnetic media, e.g., a hard drive, or optical storage； registers, or other similar types of memory elements, etc. The memory medium may include other types of memory as well or combinations thereof. In addition, the memory medium may be located in a first computer system in which the programs are executed, or may be located in a second different computer system which connects to the first computer system over a network, such as the Internet. In the latter instance, the second computer system may provide program instructions to the first computer for execution. The term “memory medium” may include two or more memory mediums which may reside in different locations, e.g., in different computer systems that are connected over a network. The memory medium may store program instructions (e.g., embodied as computer programs) that may be executed by one or more processors.

Carrier Medium –amemory medium as described above, as well as a physical transmission medium, such as a bus, network, and/or other physical transmission medium that conveys signals such as electrical, electromagnetic, or digital signals.

Programmable Hardware Element -includes various hardware devices comprising multiple programmable function blocks connected via a programmable interconnect. Examples include FPGAs (Field Programmable Gate Arrays) , PLDs (Programmable Logic Devices) , FPOAs (Field Programmable Object Arrays) , and CPLDs (Complex PLDs) . The programmable function blocks may range from fine grained (combinatorial logic or look up tables) to coarse grained (arithmetic logic units or processor cores) . A programmable hardware element may also be referred to as "reconfigurable logic” .

Computer System –any of various types of computing or processing systems, including a personal computer system (PC) , mainframe computer system, workstation, network appliance, Internet appliance, personal digital assistant (PDA) , television system, grid computing system, or other device or combinations of devices. In general, the term "computer system"can be broadly defined to encompass any device (or combination of devices) having at least one processor that executes instructions from a memory medium.

User Equipment (UE) (or “UE Device” ) –any of various types of computer systems devices which are mobile or portable and which performs wireless communications. Examples of UE devices include mobile telephones or smart phones (e.g., iPhone^TM, Android^TM-based phones) , portable gaming devices (e.g., Nintendo DS^TM, PlayStation Portable^TM, Gameboy Advance^TM, iPhone^TM) , laptops, PDAs, portable Internet devices, music players, data storage devices, or other handheld devices, etc. In general, the term “UE” or “UE device” can be broadly defined to encompass any electronic, computing, and/or telecommunications device (or combination of devices) which is easily transported by a user and capable of wireless communication.

Base Station –The term "Base Station"has the full breadth of its ordinary meaning, and at least includes a wireless communication station installed at a fixed location and used to communicate as part of a wireless telephone system or radio system.

Processing Element –refers to various elements or combinations of elements. Processing elements include, for example, circuits such as an ASIC (Application Specific Integrated Circuit) , portions or circuits of individual processor cores, entire processor cores, individual processors, programmable hardware devices such as a field programmable gate array (FPGA) , and/or larger portions of systems that include multiple processors.

Channel -amedium used to convey information from a sender (transmitter) to a receiver. It should be noted that since characteristics of the term “channel” may differ according to different wireless protocols, the term “channel” as used herein may be considered as being used in a manner that is consistent with the standard of the type of device with reference to which the term is used. In some standards, channel widths may be variable (e.g., depending on device capability, band conditions, etc. ) . For example, LTE may support scalable channel bandwidths from 1.4 MHz to 20MHz. In contrast, WLAN channels may be 22MHz wide while Bluetooth channels may be 1Mhz wide. Other protocols and standards may include different definitions of channels. Furthermore, some standards may define and use multiple types of channels, e.g., different channels for uplink or downlink and/or different channels for different uses such as data, control information, etc.

Automatically –refers to an action or operation performed by a computer system (e.g., software executed by the computer system) or device (e.g., circuitry, programmable hardware elements, ASICs, etc. ) , without user input directly specifying or performing the action or operation. Thus the term "automatically"is in contrast to an operation being manually performed or specified by the user, where the user provides input to directly perform the operation. An automatic procedure may be initiated by input provided by the user, but the subsequent actions that are performed “automatically” are not specified by the user, i.e., are not performed “manually” , where the user specifies each action to perform. For example, a user filling out an electronic form by selecting each field and providing input specifying information (e.g., by typing information, selecting check boxes, radio selections, etc. ) is filling out the form manually, even though the computer system must update the form in response to the user actions. The form may be automatically filled out by the computer system where the computer system (e.g., software executing on the computer system) analyzes the fields of the form and fills in the form without any user input specifying the answers to the fields. As indicated above, the user may invoke the automatic filling of the form, but is not involved in the actual filling of the form (e.g., the user is not manually specifying answers to fields but rather they are being automatically completed) . The present specification provides various examples of operations being automatically performed in response to actions the user has taken.

Figures 1 and 2 -Communication System

Figure 1 illustrates an exemplary (and simplified) wireless communication system. It is noted that the system of Figure 1 is merely one example of a possible system, and features of this disclosure may be implemented in any of various systems, as desired.

As shown, the exemplary wireless communication system includes a base station 102 which communicates over a transmission medium with one or

more user devices

106A, 106B, etc., through 106N. Each of the user devices may be referred to herein as a “user equipment” (UE) . Thus, the user devices 106 are referred to as UEs or UE devices.

The base station 102 may be a base transceiver station (BTS) or cell site, and may include hardware that enables wireless communication with the UEs 106A through 106N. The base station 102 may also be equipped to communicate with a network 100 (e.g., a core network of a cellular service provider, a telecommunication network such as a public switched telephone network (PSTN) , and/or the Internet, among various possibilities) . Thus, the base station 102 may facilitate communication between the user devices and/or between the user devices and the network 100.

The communication area (or coverage area) of the base station may be referred to as a “cell. ” The base station 102 and the UEs 106 may be configured to communicate over the transmission medium using any of various radio access technologies (RATs) , also referred to as wireless communication technologies, or telecommunication standards, such as GSM, UMTS (WCDMA) , LTE, LTE-Advanced (LTE-A) , New Radio (NR) , 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD) , Wi-Fi, WiMAX etc. Base station 102 and other similar base stations operating according to the same or a different cellular communication standard may thus be provided as a network of cells, which may provide continuous or nearly continuous overlapping service to UE 106 and similar devices over a wide geographic area via one or more cellular communication standards.

A UE 106 may be capable of communicating using multiple wireless communication standards. For example, a UE 106 might be configured to communicate using two or more of GSM, UMTS, CDMA2000, WiMAX, LTE, NR, WLAN, Bluetooth, one or more global navigational satellite systems (GNSS, e.g., GPS or GLONASS) , one and/or more mobile television broadcasting standards (e.g., ATSC-M/H or DVB-H) , etc. Other combinations of wireless communication standards (including more than two wireless communication standards) are also possible.

Figure 2 illustrates user equipment 106 (e.g., one of the devices 106A through 106N) in communication with the base station 102. The UE 106 may be a device with wireless network connectivity such as a mobile phone, a hand-held device, a computer or a tablet, or virtually any type of wireless device.

The UE 106 may include a processor that is configured to execute program instructions stored in memory. The UE 106 may perform any of the method embodiments described herein by executing such stored instructions. Alternatively, or in addition, the UE 106 may include a programmable hardware element such as an FPGA (field-programmable gate array) that is configured to perform any of the method embodiments described herein, or any portion of any of the method embodiments described herein.

In some embodiments, the UE 106 may be configured to communicate using any of multiple radio access technologies /wireless communication protocols. For example, the UE 106 may be configured to communicate using two or more of CDMA2000, LTE, LTE-A, NR, WLAN, or GNSS. Other combinations of wireless communication technologies are also possible.

The UE 106 may include one or more antennas for communicating using one or more wireless communication protocols. In some embodiments, the UE 106 may share one or more parts of a receive and/or transmit chain between multiple wireless communication standards. The shared radio may include a single antenna, or may include multiple antennas (e.g., for MIMO) for performing wireless communications. In other embodiments, the UE 106 may include separate transmit and/or receive chains (e.g., including separate antennas and other radio components) for each wireless communication protocol with which it is configured to communicate. In still other embodiments, the UE 106 may include one or more radios which are shared between multiple wireless communication protocols, and one or more radios which are used exclusively by a single wireless communication protocol. For example, in one set of embodiments, the UE 106 may include a shared radio for communicating using either of LTE or CDMA2000 1xRTT (among other cellular RAT combinations) , and separate radios for communicating using each of Wi-Fi and Bluetooth. Other configurations are also possible.

Figure 3 –Exemplary Block Diagram of a UE

Figure 3 illustrates an exemplary block diagram of a UE 106. As shown, the UE 106 may include a system on chip (SOC) 300, which may include portions for various purposes. For example, as shown, the SOC 300 may include processor (s) 302 which may execute program instructions for the UE 106 and display circuitry 304 which may perform graphics processing and provide display signals to the display 360. The processor (s) 302 may also be coupled to memory management unit (MMU) 340, which may be configured to receive addresses from the processor (s) 302 and translate those addresses to locations in memory (e.g., memory 306, read only memory (ROM) 350, NAND flash memory 310) and/or to other circuits or devices, such as the display circuitry 304, wireless communication circuitry 330, connector I/F 320, and/or display 360. The MMU 340 may be configured to perform memory protection and page table translation or set up. In some embodiments, the MMU 340 may be included as a portion of the processor (s) 302.

As shown, the SOC 300 may be coupled to various other circuits of the UE 106. For example, the UE 106 may include various types of memory (e.g., including NAND flash 310) , a connector interface 320 (e.g., for coupling to the computer system) , the display 360, and wireless communication circuitry (e.g., for UMTS, LTE, CDMA2000, Wi-Fi, GPS, etc. ) .

The UE device 106 may include at least one antenna, and in some embodiments multiple antennas, for performing wireless communication with base stations and/or other devices. For example, the UE device 106 may use antenna 335 to perform the wireless communication. As noted above, the UE may be configured to communicate wirelessly using multiple wireless communication standards in some embodiments.

As described further subsequently herein, the UE 106 may include hardware and software components for implementing features for determining potential non-scheduled subframes and entering optimization mode, such as those described herein with reference to, inter alia, Figures 9 and 10. The processor 302 of the UE device 106 may be configured to implement part or all of the methods described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium) . In other embodiments, processor 302 may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array) , or as an ASIC (Application Specific Integrated Circuit) . Alternatively (or in addition) the processor 302 of the UE device 106, in conjunction with one or more of the

other components

300, 304, 306, 310, 320, 330, 335, 340, 350, 360 may be configured to implement part or all of the features described herein, such as the features described herein with reference to, inter alia, Figures 9 and 10.

Figure 4 –Exemplary Block Diagram of a Base Station

Figure 4 illustrates an exemplary block diagram of a base station 102. It is noted that the base station of Figure 4 is merely one example of a possible base station. As shown, the base station 102 may include processor (s) 404 which may execute program instructions for the base station 102. The processor (s) 404 may also be coupled to memory management unit (MMU) 440, which may be configured to receive addresses from the processor (s) 404 and translate those addresses to locations in memory (e.g., memory 460 and read only memory (ROM) 450) or to other circuits or devices.

The base station 102 may include at least one network port 470. The network port 470 may be configured to couple to a telephone network and provide a plurality of devices, such as UE devices 106, access to the telephone network as described above in Figures 1 and 2.

The network port 470 (or an additional network port) may also or alternatively be configured to communicatively couple to a cellular network, e.g., a core network of a cellular service provider. The core network may provide mobility related services and/or other services to a plurality of devices, such as UE devices 106. In some cases, the network port 470 may couple to a telephone network via the core network, and/or the core network may provide a telephone network (e.g., among other UE devices serviced by the cellular service provider) .

The base station 102 may include at least one antenna 434, and possibly multiple antennas. The at least one antenna 434 may be configured to operate as a wireless transceiver and may be further configured to communicate with UE devices 106 via radio 430. The antenna 434 communicates with the radio 430 via communication chain 432. Communication chain 432 may be a receive chain, a transmit chain or both. The radio 430 may be configured to communicate via various wireless telecommunication standards, including, but not limited to, LTE, LTE-A, TDS-CDMA, WCDMA, CDMA2000, etc.

The processor 404 of the base station 102 may be configured to implement part or all of the methods described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium) . Alternatively, the processor 404 may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array) , or as an ASIC (Application Specific Integrated Circuit) , or a combination thereof.

Time-Division Multiplexing and Measurement Gaps

In time-division Long-term Evolution (TD-LTE) systems, a UE and a base station (BS) may engage in time-division (TD) multiplexing communications, e.g., whereby the UE and BS alternatively engage in uplink (UL) and downlink (DL) communications in a periodic manner. In some embodiments, the TD multiplexing communications may take place in a series of subsequent frames, wherein each frame is composed of a set of sequential subframes (in exemplary embodiments there may be 10 subframes per frame, but other numbers of subframes are also possible) . In these systems, particular subframes may be designated as UL subframes wherein the UE transmits communications to the BS, and other particular subframes may be designated as DL subframes wherein the BS transmits communications to the UE. Additionally, some particular downlink subframes may be designated as ‘special’s ubframes, whereby the special subframe indicates an upcoming switch from downlink to uplink. Different allocations of UL, DL, and special subframes may be used in various systems, according to a configuration set by the BS.

In some embodiments, an uplink or downlink communication between the UE and BS may be associated with a later acknowledgment/negative acknowledgement (ACK/NACK) feedback message (both referred to as “acknowledgement messages” , “acknowledgement feedback” , or “ACK/NACK” feedback herein) . The ACK/NACK feedback message may specify whether the communication was successfully received and decoded. For example, if the UE receives a DL message from the BS in a particular subframe, the UE may be scheduled to send an ACK/NACK message to the BS in a specific subsequent UL subframe, depending on the subframe configuration. For example, each DL subframe may be associated with a particular subsequent ACK/NACK UL subframe, depending on the subframe configuration. Similarly, if the UE sends an UL message to the BS in a particular UL subframe, the BS may be scheduled to respond with an ACK/NACK feedback in a specific subsequent DL subframe, depending on the configuration. For example, Table 10.1.3.1-1 illustrates ACK/NACK subframe allocation for the uplink for a variety of subframe configurations.

Table 10.1.3.1-1： Downlink association set index K: {k₀， k₁， L k_M-1} for TDD

As illustrated in Table 10.1.3.1-1, for UL/DL configuration 2, the subframe index for uplink subframe 2 is {8, 7, 4, 6} , indicating that the downlink subframes which are scheduled to receive corresponding ACK/NACK feedback in uplink subframe 2 should be (2 – {8, 7, 4, 6} ) mod 10 ＝ {4, 5, 8, 6} . This means that, in this embodiment, if the UE receives downlink grants for PDSCH in

downlink subframes

4, 5, 6 and 8, then the UE should send ACK/NACK feedback in the subsequent subframe 2. Additionally, in configuration 2, the subframe index for UL subframe 7 is {8, 7, 4, 6} , indicating that downlink subframes (7- {8, 7, 4, 6} ) mod 10 ＝ {9, 0, 3, 1} are scheduled for ACK/NACK feedback in the subsequent UL subframe 7.

In some embodiments, the UE may periodically perform a measurement gap, wherein the UE may perform various measurements (e.g., inter-frequency measurements) , which may result in the UE being incapable of receiving or transmitting messages to or from a base station (BS) or eNB. In various embodiments, the measurement gap may be initiated for a variety of reasons. For example, the UE may perform quality measurements on the camped-on base station during the measurement gap. The measurements may be performed at the same frequency or at a different frequency from that which the UE was previously communicating on, such that a radio of the UE may be retuned during the measurement gap. In other embodiments, the UE may perform measurements on other BSs during the measurement gap, e.g., neighboring base stations. Because the UE may not be responsive to the BS during the measurement gap, the BS may decide not to schedule some downlink subframes that occur prior to measurement gap if the corresponding ACK/NACK feedback message is scheduled to occur during the measurement gap (e.g., because the UE would be unable to send the ACK/NACK feedback during the measurement gap) . Note that the UE could also be configured to determine the same situation (that the downlink subframes may not be scheduled due to the feedback message occurring during the measurement gap) , and as discussed below, may then be able to reallocate resources that would have been used to receive downlink transmissions during those downlink subframes for other purposes (e.g., powering those resources off, using them to extend the measurement gap, etc. Thus, the UE may be able to predict that the BS will not use those subframes for downlink transmission based on the fact that the BS is aware that the UE will not be able to respond to them due to the measurement gap. Accordingly, the UE may be configured to assume these downlink subframes will not be used and are thus potential non-scheduled subframes. As noted below, this assumption may be verified by determining that they are not scheduled by the BS for one or more frames that include a measurement gap.

Figure 5 –Exemplary Subframe Configuration with Measurement Gap

Figure 5 illustrates a particular subframe configuration with a measurement gap, according to one embodiment. The illustrated subframe configuration corresponds to configuration 2 of Table 10.1.3.1-1, where the subframe offset of the measurement gap is 3. The subframe offset indicates the first subframe of the measurement gap (i.e., in Figure 5, the measurement gap begins at subframe 3) .

As explained above and as shown in Figure 5, ACK/NACK feedback associated with DL subframes {4, 5, 6, 8} is scheduled to occur in the subsequent UL subframe 2. Similarly, ACK/NACK feedback associated with DL subframes {9, 0, 3, 1} is scheduled to occur in the subsequent UL subframe 7. In the illustrated embodiment, a downlink message included within the shaded

subframes

9, 0 and 1 are scheduled to receive an UL ACK/NACK feedback message in the indicated subframe 7, which as illustrated, will occur during the measurement gap. In this embodiment, the BS may decide to not schedule any downlink transmissions for the

shaded subframes

9, 0 and 1, since the UE may not be able to transmit the ACK/NACK feedback associated with such downlink messages.

In other embodiments with different UL/DL configurations and different GAP offsets, the pattern for subframes which will not be scheduled may be different. In general, subframes which may not be scheduled because their corresponding ACK/NACK feedback will occur during a measurement gap may be referred to as “potential non-scheduled subframes” .

Figure 6 –Exemplary Subframe Configuration and Associated Potential Non-scheduled Subframes

Figure 6 illustrates another exemplary embodiment with UL/DL configuration 2 and gap offset 1. In this embodiment, the slashed

subframes

4, 5, 6 and 8 are associated with an ACK/NACK message in the subsequent UL subframe 2 that is included within the measurement gap, and these slashed subframes are potential non-scheduled subframes. Furthermore, in this embodiment, for the slashed uplink subframe 7, an uplink grant for transmission of a physical uplink shared channel (PUSCH) message would have been received in a DL subframe included within the measurement gap. In this embodiment, the PUSCH message may not be sent in the slashed UL subframe due to the lack of an UL grant. Alternatively, the slashed UL subframe may be scheduled to send ACK/NACK feedback associated with the

previous DL subframes

1 and 3 that are included within the measurement gap. The BS may decide to not schedule communications for these DL subframes within the measurement gap since the UE is not responsive during the measurement gap, and as a result, the slashed UL subframe may not be utilized for transmitting ACK/NACK feedback by the UE.

Because of this, the slashed UL subframe may be considered a potential non-scheduled subframe. This slashed UL subframe may alternatively be utilized for transmission of a sounding reference signal (SRS) , a physical uplink control channel (PUCCH) message, or a physical random access channel (PRACH) message. However, if the UE determines that the slashed UL subframe is additionally not scheduled for transmission of SRS, PUCCH, or PRACH, it may likewise be considered a potential non-scheduled subframe. For example, in some embodiments the UE may be configured to send SRS periodically. The period and offset may be calculated based on RRC signaling, and the UE may determine whether a particular UL subframe is scheduled for SRS. In general, the UE may be aware of the subframe locations for each of SRS/PUCCH/PRACH in advance, and may thereby be able to determine whether a particular UL subframe may be designated a potential non-scheduled subframe.

Thus, “potential non-scheduled subframes” may include both DL and UL subframes that may not be scheduled or utilized due to the measurement gap. Accordingly, in various embodiments, potential non-scheduled subframes may occur either before or after a measurement gap. For example, in some embodiments, regular downlink and special downlink subframes that may be identified as potential non-scheduled subframes may occur before a measurement gap, while uplink subframes that may be identified as potential non-scheduled subframes may occur after a measurement gap.

Figure 7 – Exemplary UL/DL configurations

Figure 7 illustrates sets of potential non-scheduled subframes for a variety of different UL/DL configurations and gap offsets. In Figure 7, the dark shaded subframes indicate subframes that occur during a measurement gap. The potential non-scheduled subframes for each UL/DL configuration and for each measurement gap offset are illustrated as slashed subframes.

Figure 8 - PHICH detection during DL subframe

Figure 8 shows an embodiment wherein the slashed downlink subframe located at frame 0 and subframe 9 is scheduled for detection of a physical hybrid-ARQ indicator channel (PHICH) message. In some embodiments, PHICH detection may depend on the UL grant schedule of the UE, as illustrated below in Table 9.1.2-1.

Table 9.1.2-1： k_PHICHfor TDD

Table 9.1.2-1 illustrates, for a variety of UL/DL configurations, which subframe a UE should use to detect a PHICH message, depending on the subframe in which a PUSCH message was sent, in some embodiments. For instance, in UL/DL configuration 2, if a PUSCH message is sent in subframe 2, then the UE should detect the PHICH message in subframe 2+k which is subframe 8 (since k＝6) , as indicated in the table. In other words, in some embodiments, whether a PHICH message should be detected may depend on the network’s UL schedule.

In these embodiments, depending on the control format indicator (CFI) number, the PHICH message may only occupy some of the symbols in the subframe, such that the remaining symbols may be utilized for another purpose. For example, in some embodiments the PHICH message may only occupy the first OFDM symbol of a subframe, such that the remaining symbols may be utilized for another purpose, as described in further detail below. In other embodiments, the mapping of PHICH may only occupy the first 1, 2, or any number of symbols of the subframe (e.g., depending on high layer signaling, such as PHICH duration) . In these embodiments, as described in detail below, the UE can power off the transmitter or expand the measurement gap in the remained symbols that are not occupied for PHICH messaging.

Leveraging Potential Non-scheduled Subframes

In some embodiments, potential non-scheduled subframes may be leveraged to improve the functionality of the UE. In other words, the UE may be configured to reallocate resources associated with the potential non-scheduled subframes. Alternatively or in addition, the UE may reallocate resources associated with some of the symbols comprised within a particular subframe (e.g., if only a subset of the symbols within a subframe are used for PHICH detection, as described above) . When a UE is operating according to these reallocated resources, the UE may be said to be operating in a ‘reallocation mode’ or a ‘optimization mode’ . For example, in some embodiments, entering the reallocation mode may comprise a transmitter/receiver of the UE being powered down during a potential nonscheduled UL/DL subframe to reduce power consumption of the UE. In other embodiments, as explained in further detail below, the reallocation mode may comprise extending the measurement gap to include the potential non-scheduled subframes to provide improved Global System for Mobile Communications (GSM) measurement during the measurement gap.

In a Single Radio Voice Call Continuity (SRVCC) scenario, a UE may utilize a measurement gap to detect the base station identity code (BSIC) , which in some embodiments may be sent periodically (for example, the BSIC may be sent every 46.15ms, or with some other periodicity) . In these embodiments, the UE may retune its radio to detect the BSIC during the measurement gap. In these embodiments, since the duration of the measurement gap may be shorter than the periodicity within which the BSIC is sent, the UE may need to use multiple measurement gaps before the BSIC signal is successfully detected. In some embodiments, some or all of the potential non-scheduled subframes may be leveraged to increase the duration of the measurement gap, and the probability of successful BSIC detection may be increased.

In some embodiments, the mechanism for the detection of potential non-scheduled downlink subframes may proceed as follows. First, the parameters of the measurement gap may be configured. It may then be determined if one or more downlink subframes have not been scheduled for multiple consecutive measurement gaps. For example, the UE may wait until specific downlink subframes have not been scheduled for four consecutive gaps before resources are reallocated for these specific downlink subframes. Accordingly, the UE may turn on the reallocation or power saving mode.

AUE may be required to detect a BSIC for various reasons. As one non-limiting example, a B2 event may occur that may initiate BSIC detection. A B2 event is defined in 3GPP 36.331 as occurring when a first signal quality associated with a primary cell (PCell) falls below a first quality threshold, while a second signal quality associated with a neighboring cell rises above a second quality threshold. Once B2 is configured from the network, the UE may initiate an attempt to detect a valid BSIC during the measurement gap. In these embodiments, if no valid BSIC is detected, then the potential non-scheduled subframes may be leveraged for GSM BSIC detection. In other words, the potential non-scheduled subframes may be utilized to extend the duration of a subsequent measurement gap, to improve the probability of a successful BSIC detection.

Figure 9 –Method for reallocating resources for DL subframes

Figure 9 is a flow chart diagram illustrating an exemplary method by which resources may be reallocated for DL subframes, according to some embodiments.

As illustrated, at 902, the UE may determine that one or more DL subframes are scheduled to receive ACK/NACK feedback during an UL subframe included within a measurement gap. The UE may designate these DL subframes as potential non-scheduled subframes, which may receive a reallocation of resources as discussed below.

In some embodiments, the one or more DL subframes may additionally be required to have not been scheduled for a plurality of consecutive measurement gaps before their resources may be reallocated (e.g., before the reallocation mode is entered) . For example, it may be required for the one or more DL subframes to not have been scheduled over four consecutive measurement gaps (or some other number of consecutive measurement gaps) before they are designated as potential non-scheduled subframes. However, in other embodiments, the UE may also designate these DL subframe (s) for reallocation immediately, without ensuring they have not been scheduled for one or more measurement gaps.

At 904, the UE may reallocate resources of the one or more DL subframes based on the determination (e.g., upon entering a reallocation mode) . In particular, in response to determining that the DL subframe (s) are associated with uplink subframe (s) within the measurement gap (e.g., where the uplink subframe (s) would have been used for an acknowledgement message of those DL subframe (s) , but cannot because the uplink subframe (s) fall within the measurement gap) , the UE may reuse those DL subframe (s) for other purposes.

For example, the reallocation of resources may comprise powering off a receiver of the UE during the one or more DL subframes to preserve power. Alternatively, in some embodiments the reallocation of resources may comprise extending the measurement gap to include the determined one or more DL subframes. In some embodiments, the UE may determine to reallocate resources in response to a failure to detect a valid BSIC. For example, the UE may reallocate resources only if the UE has recently failed to detect a valid BSIC. Note that the extended measurement gap may be used for various other measurements or procedures as well, as desired. For example, the additional DL subframe (s) may be used to perform interfrequency measurements, neighboring base station measurements, etc.

Figure 10 –Method for reallocating resources for UL subframes

Figure 10 is a flow chart diagram illustrating an exemplary method by which resources may be reallocated for UL subframes, according to some embodiments.

As illustrated, at 1002, the UE may determine that one or more UL subframes are potential non-scheduled subframes, which may receive a reallocation of resources, e.g., in a reallocation mode. In some embodiments, the determination may be based on a determination that the one or more UL subframes are scheduled to transmit ACK/NACK feedback for DL subframes included within a measurement gap. Alternatively or in addition, the one or more UL subframes may be determined to be potential non-scheduled subframes if an uplink grant for transmission of a physical uplink shared channel (PUSCH) message during the one or more uplink subframes would have been received in a DL subframe included within the measurement gap. Alternatively or in addition, the one or more UL subframes may be determined to be potential non-scheduled subframes if the UE determines that the one or more UL subframes are not scheduled for transmission of SRS, PUCCH, or PRACH.

At 1004, the UE may reallocate resources to the one or more UL subframes based on the determination (e.g., within a reallocation mode) . In particular, in response to determining that the UL subframe (s) are associated with downlink subframe (s) that fall within the measurement gap (e.g., where the uplink subframe (s) would have been used for an acknowledgement message of those DL subframe (s) , but cannot because the downlink subframe (s) fall within the measurement gap) , the UE may reuse those UL subframe (s) for other purposes.

Similar to discussions above in 904, in some embodiments, the reallocation of resources may comprise powering off a transmitter of the UE during the one or more UL subframes to preserve power. Alternatively, in some embodiments the reallocation of resources may comprise extending the measurement gap to include the determined one or more UL subframes. In some embodiments, the UE may determine to reallocate resources in response to a failure to detect a valid BSIC. For example, the UE may enter an optimization mode and reallocate resources only if the UE has recently failed to detect a valid BSIC. Note that the extended measurement gap may be used for various other measurements or procedures as well, as desired. For example, the additional DL subframe (s) may be used to perform interfrequency measurements, neighboring base station measurements, etc.

Figure 11 –Exiting Reallocation Mode

Figure 11 illustrates subframe allocation for an instance wherein it may be desirable for a UE to exit reallocation mode (or otherwise cease reallocation of resources of certain subframes) , according to some embodiments. In these embodiments, if a UE enters reallocation mode, it may fail to detect a DL schedule during a DL subframe whose resources have been reallocated. As illustrated in Figure 9, the UE may fail to detect the DL schedule in the

white subframes

9, 0, and 1, and the UE may then fail to receive a transmission during the measurement gap. As illustrated, the UE may then receive an initial downlink transmission in the subsequent subframe 3 with a redundancy version (RV) not equal to 0. Because the received initial downlink transmission had a RV not equal to 0, the UE may determine that a previous downlink transmission (i.e., with an RV equal to 0) may have been sent during either the potential non-scheduled subframe or the measurement gap. In this embodiment, the UE may determine to exit the reallocation mode (or otherwise cease reallocation of resources of these potential non-scheduled subframes) , to avoid missing further DL schedules. In other words, the UE may determine to revert the reallocation of resources that was introduced by the reallocation mode.

In some embodiments, the UE may monitor the DL channel for a particular number of subframes (e.g., 15 subframes in the illustrated embodiment, or some other number of subframes) after the measurement gap, to determine whether an initial DL transmission is received with an RV not equal to 0. For example, the network may typically schedule DL retransmission at regular intervals (e.g., every 10ms, or some other interval) , and the UE may monitor the DL channel for a transmission with an RV not equal to 0 for a duration slightly longer than this interval (e.g., 15ms in the example of Figure 9) . If no transmission is detected with a nonzero RV during this duration, the UE may continue functioning in the reallocation mode. Note that other detections may be used to exit the reallocation mode. In general, any indication that the potential non-scheduled subframe (s) were actually scheduled by the BS may cause the UE to exit the reallocation mode or otherwise modify operation to adjust for the actions of the BS.

In some embodiments, the UE may leverage the potential non-scheduled uplink subframes if no PUSCH/PUCCH/SRS/PRACH transmission is scheduled regardless of the measurement gap pattern. In some embodiments, if the uplink subframe is adjacent to the measurement gap, then the uplink subframe may be leveraged for GSM BSIC detection when B2 is configured and no valid BSIC detected.

Embodiments of the present disclosure may be realized in any of various forms. For example, some embodiments may be realized as a computer-implemented method, a computer-readable memory medium, or a computer system. Other embodiments may be realized using one or more custom-designed hardware devices such as ASICs. Still other embodiments may be realized using one or more programmable hardware elements such as FPGAs.

In some embodiments, a non-transitory computer-readable memory medium may be configured so that it stores program instructions and/or data, where the program instructions, if executed by a computer system, cause the computer system to perform a method, e.g., any of a method embodiments described herein, or, any combination of the method embodiments described herein, or, any subset of any of the method embodiments described herein, or, any combination of such subsets.

In some embodiments, a device (e.g.， a UE 106) may be configured to include a processor (or a set of processors) and a memory medium, where the memory medium stores program instructions, where the processor is configured to read and execute the program instructions from the memory medium, where the program instructions are executable to implement any of the various method embodiments described herein (or, any combination of the method embodiments described herein, or, any subset of any of the method embodiments described herein, or, any combination of such subsets) . The device may be realized in any of various forms.

Although the embodiments above have been described in considerable detail, numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications.

Claims

A method for reallocating resources to subframes in a time-division (TD) multiplexing communication system, the method comprising:

by a user equipment device (UE) comprising a processor coupled to a radio:

determining that one or more downlink subframes are associated with an uplink subframe that is included within a measurement gap, wherein messages transmitted during the one or more downlink subframes are scheduled to receive a corresponding acknowledgement message during the uplink subframe； and

reallocating resources during the one or more downlink subframes in response to the determination that the one or more downlink subframes are associated with the uplink subframe that is included within the measurement gap.
The method of claim 1,

wherein the reallocation of resources comprises powering off a receiver coupled to the radio during the determined one or more downlink subframes.
The method of claim 1,

wherein the reallocation of resources comprises extending the measurement gap to include the determined one or more downlink subframes.
The method of claim 3,

wherein the extended measurement gap is utilized by the UE to detect a base station identity code (BSIC) .
The method of claim 4, the method further comprising:

attempting to detect a valid BSIC；

wherein the resources are reallocated further in response to a failure to detect a valid BSIC.
The method of claim 1, the method further comprising:

determining that the one or more downlink subframes have not been scheduled over a plurality of measurement gaps； and

wherein said reallocation of resources to the one or more downlink subframes is further based on the determination that the one or more downlink subframes have not been scheduled over a plurality of measurement gaps.
The method of claim 1, the method further comprising:

determining that a received redundancy version (RV) is not equal to zero；

reverting the reallocated resources in response to the determination that the received RV is not equal to zero.
A method for reallocating resources to subframes in a time-division (TD) multiplexing communication system, the method comprising:

by a user equipment device (UE) comprising a processor coupled to a radio:

determining that one or more uplink subframes are potential non-scheduled subframes； and

reallocating resources during the one or more uplink subframes in response to the determination that the one or more uplink subframes are potential non-scheduled subframes.
The method of claim 8,

wherein the determination that the one or more uplink subframes are potential non-scheduled subframes is based on a determination that the one or more uplink subframes are associated with one or more downlink subframes that are included within a measurement gap, wherein messages received during the one or more downlink subframes are scheduled for transmission of a corresponding acknowledgement message during the one or more uplink subframes.
The method of claim 8,

wherein the determination that the one or more uplink subframes are potential non-scheduled subframes is based on a determination that an uplink grant for transmission of a physical uplink shared channel (PUSCH) message during the one or more uplink subframes would have been received in a downlink subframe included within a measurement gap.
The method of claim 8,

wherein the reallocation of resources comprises powering off a transmitter coupled to the radio during the determined one or more uplink subframes.
The method of claim 8,

wherein the reallocation of resources comprises extending the measurement gap to include the determined one or more uplink subframes.
The method of claim 10,

wherein the extended measurement gap is utilized by the UE to detect a base station identity code (BSIC) .
The method of claim 11, the method further comprising:

attempting to detected a valid BSIC；

wherein the resources are reallocated further in response to a failure to detect a valid BSIC.
The method of claim 10,

wherein said reallocating resources is further in response to a determination that the one or more uplink subframes are adjacent to the measurement gap.
A user equipment device (UE) , comprising:

a radio； and

one or more processors coupled to the radio；

wherein the one or more processors and the radio are configured to perform time-division (TD) multiplexing communications with a remote device, wherein said TD multiplexing communications comprise a temporal series of downlink subframes and uplink subframes；

wherein one or more of the downlink subframes are associated with one or more of the uplink subframes, wherein said association implies that an acknowledgement message associated with the one or more downlink subframes is scheduled for transmission during the one or more uplink subframes；

wherein the processor is configured to:

determine that either the one or more downlink subframes or the one or more uplink subframes are included within a measurement gap；

wherein the radio is configured to:

reallocate resources during one or more first subframes, wherein the one or more first subframes are the other of the one or more downlink subframes and the one or more uplink subframes.
The UE of claim 16,

wherein the reallocation of resources comprises powering off a receiver coupled to the radio during the one or more first subframes.
The UE of claim 16,

wherein the reallocation of resources comprises extending the measurement gap to include the one or more first subframes.
The UE of claim 18,

wherein the extended measurement gap is utilized by the UE to detect a base station identity code (BSIC) .
The UE of claim 16, wherein the one or more processors and the radio are further configured to:

determine that the one or more first subframes have not been scheduled over a plurality of measurement gaps； and

wherein said reallocation of resources is further based on the determination that the one or more first subframes have not been scheduled over a plurality of measurement gaps.