BR112017025532B1 - ADAPTABLE FRAME STRUCTURE SYSTEMS AND METHODS FOR TIME-DIVISION DUPLEX - Google Patents

Abstract

ADAPTABLE FRAME STRUCTURE SYSTEMS AND METHODS FOR TIME-DIVISION DUPLEX. Transmissions that communicate time division duplex (TDD) scaling interval in a first direction may include one or more regions to communicate in a second direction, wherein the first direction is a transmit direction and the second direction is a reception direction or vice versa. A radio frame may include TDD scheduling intervals with such regions and/or TDD scheduling intervals without such regions for wireless communication, and these TDD scheduling intervals may further be configured according to different frame structure configurations, such as different scaling interval lengths, subcarrier spacings, or symbol durations.

Description

FIELD OF TECHNIQUE

[001] The present application relates to wireless communications and, specifically, adaptive frame structure methods and systems for duplex time division.

BACKGROUND

[002] In a wireless communications system, transmissions are generally communicated according to predefined fixed frame structures. Fixed frame structures are used so that communication devices are aware of resources, such as time, frequency, or time and frequency resources; and interference between different resources and between transmitting and receiving signals can be avoided or reduced. Modern wireless networks are increasingly used to support communications across diverse traffic types. Different types of traffic may have different characteristics and quality of service (QoS) requirements, such as latency, which fixed frame structures may be unable to accommodate. Consequently, adaptable frame structures that can efficiently support different types of traffic are desired.

SUMMARY OF THE INVENTION

[003] Technical advantages are generally achieved by embodiments of this disclosure that describe adaptive frame structure systems and methods for duplex time division.

[004] According to one embodiment, a method for wireless communications is provided. The method includes communicating, by a device, a first data transmission in a first time division duplexing (TDD) scheduling interval in a first direction. The first TDD scheduling interval is configured with a first frame structure configuration. The method further includes communicating, by the device, a second data transmission in the first TDD scheduling interval in a second direction. One of the first direction and the second direction is a transmit direction, and the other of the first direction and the second direction is a receive direction.

[005] According to another embodiment, a method for wireless communications is also provided. The method includes assigning, by a network controller, a frame structure configuration to communicate in a time division duplexing (TDD) scheduling interval in a first direction in a frequency subband. The frame structure configuration corresponds to a set of frame parameters. The method further includes selecting, by the network controller, a switching type for the TDD scheduling interval. The switching type indicates whether or not the TDD scheduling interval includes at least one transmission opportunity to communicate in a second direction. One of the first direction and the second direction is a transmit direction, and the other of the first direction and the second direction is a receive direction. The method also includes sending an indication indicating communication of orthogonal frequency division multiplexing (OFDM) signals in the TDD scheduling interval according to the set of frame parameters and the selected switching type.

BRIEF DESCRIPTION OF THE DRAWINGS

[006] For a more complete understanding of the present disclosure, and the advantages thereof, reference is now made to the following description taken in conjunction with the attached drawings, in which:

[007] Figure 1 is a block diagram of a wireless communications network modality;

[008] Figure 2A is a diagram of a downlink TDD TTI embodiment;

[009] Figure 2B is a diagram of another downlink TDD TTI modality;

[010] Figure 3A is a diagram of a TDD uplink TTI embodiment;

[011] Figure 3B is a diagram of another TDD uplink TTI embodiment;

[012] Figure 3C is a diagram of another TDD uplink TTI embodiment;

[013] Figure 3D is a diagram of another TDD uplink TTI modality;

[014] Figure 4 is a diagram of another downlink TDD TTI modality;

[015] Figure 5 is a diagram of another TDD uplink TTI embodiment;

[016] Figure 6 is a modality diagram of TDD TTIs with different frame structure configurations and switching types;

[017] Figure 7 illustrates tables to represent different frame structure configurations and switching types;

[018] Figure 8 is another table to represent different frame structure configurations and switching types;

[019] Figure 9 is a diagram of a TDD framework modality;

[020] Figure 10 is a diagram of another type of TDD framework;

[021] Figure 11 is a diagram of yet another type of TDD framework;

[022] Figure 12 is a diagram of yet another type of TDD framework;

[023] Figure 13 is a diagram of yet another type of TDD framework;

[024] Figure 14 is a diagram of yet another type of TDD framework;

[025] Figure 15 is a diagram of a TDD board using special OFDM symbols to align GPs across frequency sub-bands;

[026] Figure 16 is a diagram of yet another type of TDD framework;

[027] Figure 17 is a diagram of a method for wireless communications;

[028] Figure 18 is a block diagram of a modality processing system; It is

[029] Figure 19 is a block diagram of a transceiver.

[030] Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated. Figures are drawn to clearly illustrate relevant aspects of the embodiments and are not necessarily drawn to scale.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[031] The manufacture and use of embodiments are discussed in detail below. It should be noted, however, that the concepts disclosed herein can be incorporated in a wide variety of specific contexts, and that the specific embodiments discussed herein are merely illustrative and do not serve to limit the scope of the claims. Furthermore, it should be understood that various changes, substitutions and alterations may be made herein without departing from the spirit and scope of the appended claims.

[032] In the present disclosure, a “transmission time interval” (TTI) or “scheduling interval” corresponds to the interval between the beginning of the time scheduled by a scheduling control signaling instance, and the beginning of the time scheduled by the next instance of scheduling control signaling. The duration of a scheduling interval can be measured or specified in units of time (e.g. 1ms) or in symbols (e.g. 14 OFDM symbols). The duration of a scheduling interval can be fixed or configurable, and can vary depending on other wireless communication parameters such as subcarrier spacing.

[033] Embodiments described herein communicate data transmissions in opposite directions in the same time division duplex (TDD) transmission time interval (TTI). In one example, a downlink TDD TTI includes a region for uplink transmissions. In another example, a TDD uplink TTI includes a region for downlink transmissions. Regions in a TDD TTI that carry transmissions in a direction opposite to that of the TDD TTI are herein referred to as opposite regions. An opposing region in a TDD TTI may carry data (i.e., an opposing data region) and/or feedback information (i.e., an opposing feedback region), such as a Hybrid Automatic Retry Request (HARQ) message of accuse (ACK)/negative accuse (NACK). In an example, a TTI of TDD may include an opposite region for carrying data, and another opposite region for carrying return information. In an example like this, the opposing regions may encompass different time domain features or different frequency domain features.

[034] Embodiments of the present disclosure also provide systems and methods for communicating orthogonal frequency division multiplexing (OFDM) signals in a TDD frame having TDD TTIs configured with different frame structure configurations and TTI switching types. As used herein, a TDD frame refers to a frame that carries signals in TDD TTIs. Different frame structure configurations can utilize different sets of frame parameters including a subcarrier spacing (SC), a TTI length, a cyclic prefix length (CP), and a symbol duration. Different TTI switching types indicate different configurations of opposing data regions and opposing return regions included in TDD TTIs. In one embodiment, the TDD TTIs in the TDD frame in different OFDM frequency subbands have different TTI lengths and/or different subcarrier spacings. In another embodiment, the TDD TTIs in the TDD frame in the same OFDM frequency subband have different TTI lengths and/or different subcarrier spacings. In yet another embodiment, the TDD TTIs in the TDD frame in different OFDM frequency subbands are configured to have different TTI switching types. In yet another embodiment, the TDD TTIs in a frame in the same OFDM frequency subband are configured to have different TTI switching types. In yet another embodiment, a TDD TTI in the TDD frame includes zero, one or more opposing regions. Guard periods (GPs) are included in a TDD frame to separate downlink and uplink transmissions and are aligned in the time domain across frequency subbands. Configuration information of a TDD TTI, such as frame structure configuration, TTI switching type, and frequency subband of the TDD TTI, can be predefined, defined dynamically or semi-statically, and signaled to UEs. A signaling can be transmitted via broadcast, multicast or unicast dynamically, semi-statically or statically.

[035] Figure 1 is a network 100 for communicating data. The network 100 comprises a base station 110 having a coverage area 101, a plurality of mobile devices 120, and a backhaul network 130. As shown, the base station 110 establishes uplink connections (dashed line ) and/or downlink (dotted line) with mobile devices 120, which serve to port data from mobile devices 120 to a base station 110 and vice versa. Data carried over the uplink/downlink connections may include data communicated between mobile devices 120, as well as data communicated to/from a remote end (not shown) via the backhaul network 130. As used herein document, the term “base station” refers to any component (or collection of components) configured to provide wireless access to a network, such as an enhanced base station (eNB), a macrocell, a femtocell, an access (AP) to Wi-Fi, or other wireless enabled devices. Base stations can provide wireless access in accordance with one or more wireless communication protocols, for example, Long Term Evolution (LTE), LTE Enhanced (LTE-A), High Speed Packet Access (HSPA), WiFi 802.11a/b/g/n/ac, etc. As used herein, the term “mobile device” refers to any component (or collection of components) that can establish a wireless connection with a base station, such as a user equipment (UE), a mobile station ( STA), and other wireless enabled devices. In some embodiments, network 100 may comprise various other wireless devices, such as relays, low power nodes, etc.

[036] Although the network 100 is shown having a single base station 110, it should be understood that the network 100 may include multiple base stations 110. The operations of one or more of the base stations 110 may be controlled by a controller that is either co-located with one of the base stations 110 or located elsewhere on the network in communication with the one or more base stations 110.

[037] Transmissions between a base station and a mobile device are generally communicated in transmission time slots (TTIs) (or “subframes”) according to predefined frame structure configurations. As used herein, “communicating a transmission” refers to transmitting or receiving the transmission. Transmissions may include data, control information, and/or feedback information, such as Hybrid Automatic Repeat Request (HARQ) acknowledge (ACK)/negative acknowledge (NACK) messages. A frame structure configuration typically specifies a combination of frame parameters, such as subcarrier spacing (SC), TTI length, cyclic prefix length (CP), and symbol duration. TTI lengths affect the latency performance and throughput performance of a network. Specifically, shorter TTIs achieve superior latency performance by providing more frequent transmission opportunities, and longer TTIs achieve superior throughput performance by reducing excessive signaling.

[038] In general, a TTI is designed for transmissions in either an uplink direction or a downlink direction, which may be referred to as the TTI transmission direction, and thus a TTI may be referred to as a downlink TTI uplink or a downlink TTI. In some embodiments, a TTI may be configured to include a region for transmissions in a direction opposite to the transmission direction of the TTI. For example, a downlink TTI contains a region for an uplink transmission, or an uplink TTI contains a region for a downlink transmission.

[039] Figure 2A is an embodiment of downlink TTI 200 in a time division duplex (TDD) communications network. The TDD 200 TTI includes regions for uplink transmissions. As shown, the downlink TDD TTI 200 includes regions 201-206 divided into the time domain. Region 201 is allocated for downlink control channels, which can be used, for example, to send scheduling information for uplink data transmissions. Region 202 is for downlink data transmissions, which may be scheduled or grant-free transmissions. Region 204 is allocated for an uplink data transmission, and region 205 is for transmission of uplink feedback information, such as an uplink ACK/NACK message acknowledging receipt of a previous downlink data transmission. . For example, the uplink ACK/NACK message is communicated to acknowledge receipt of a downlink data transmission communicated in a previous downlink TDD TTI or in region 202 of the downlink TDD TTI 200. As used in Herein, region 204 is referred to as a TTI-opposite data region of TDD 200, and region 205 is referred to as a TTI-opposite return region of TDD 200.

[040] In the example shown in Figure 2A, region 204 and region 205 are divided into the time domain, that is, the uplink data transmission in region 204 and the uplink ACK/NACK message in region 205 are communicated in a time division multiplexed mode. Regions 204 and 205 may be viewed as uplink transmission opportunities (TOs) for uplink transmissions of, for example, low latency uplink traffic or ACK/NACK messages, and may contain one or more symbols or orthogonal frequency division multiplexing (OFDM) slots. Data transmissions in region 204 can be scheduled or lease-free to provide additional flexibility for data transmissions for different applications and devices. For example, a mobile device may transmit data in region 204 after receiving a grant from a base station. In another example, multiple mobile devices can compete for region 204 using a contention-based scheme that is enforceable. Grant-free data transmissions may be beneficial to support communications for particular devices or requests in a wireless network, such as, but not limited to, machine-type communication (MTC). MTC may occur as part of the “Internet of Things,” where a low data rate may be acceptable or warranted by the use of less complex or costly transmitters, receivers, and data power sources. Where communication from a machine to a network includes a status update, sensor reading, alarm or the like, the requirement for a high data rate is less likely. Such transmissions may include large numbers of communications of relatively small packet size and require a relatively low data rate. Similar characteristics may occur for downlink transmissions from the network to the device or machine. Scheduling these types of transmissions can be inefficient due to incurring excess signaling for small packet transmissions, the latency of a scheduling request and grant procedure, and the power consumption incurred by a transmitting device or access point to deal with this excess and delay. Region 203 is a guard period (GP) separating downlink transmissions in regions 201-202 and uplink transmissions in regions 204-205. The GP 203 can help reduce interference when switching between uplink and downlink transmissions in the TDD network. Region 206 is a guard period, which separates downlink transmissions in regions 201-202 from preceding uplink transmissions. It should be understood that no guard period is required before a downlink transmission that is not preceded by an uplink transmission.

[041] It is considered that region 201 could alternatively or additionally include pilot signals or reference signals. It is further considered that region 201 could be used to transmit a control signal indicating whether or not the TTI of TDD 200 is an uplink TTI or a downlink TTI.

[042] Figure 2B is an embodiment of downlink TTI 250 in a time division duplex (TDD) communications network. The TDD TTI 250 includes regions for uplink transmissions. As shown, the downlink TDD TTI 250 includes regions 251-256 divided into the time domain. Region 251 is allocated for downlink channels. Region 251 may be used, for example, to send control signals such as scheduling information for uplink data transmissions, pilot signals, or reference signals. Region 251 may also be used for downlink data transmissions, which may be scheduled or grant-free transmissions. The downlink control signals and data transmissions may each use contiguous time-frequency resources within region 251, or may be interleaved within region 251 in any suitable manner. In particular, the control signals in region 251 and the data signals in region 251 are not necessarily divided into the time domain. Region 254 is allocated for uplink data transmissions, and for transmitting uplink feedback information, such as measurement information (e.g. channel quality feedback, resonance reference signal), an ACK/NACK message from uplink acknowledging receipt of a previous downlink data transmission. For example, the uplink ACK/NACK message is communicated to acknowledge receipt of a downlink data transmission communicated in a previous downlink TDD TTI or in region 251 of the downlink TDD TTI 250. Uplink data and uplink feedback information may each use contiguous time-frequency resources within region 254, or may be interleaved within region 254 in any suitable manner. In particular, the uplink data transmissions in region 254 and the uplink feedback information in region 254 are not necessarily divided into the time domain. As used herein, region 254 is referred to as a TTI opposite and return data region of TDD 250.

[043] In the example shown in Figure 2B, region 254 can be viewed as an uplink transmission (TO) opportunity for uplink transmissions of, for example, low latency uplink traffic or ACK/NACK messages. , and may contain one or more orthogonal frequency division multiplexing (OFDM) symbols or slots. Data transmissions in region 254 can be scheduled or lease-free to provide additional flexibility for data transmissions for different orders and devices. For example, a mobile device may transmit data in region 254 after receiving a grant from a base station. In another example, multiple mobile devices may compete for region 254 using an applicable contest-based scheme. Grant-free data transmissions may be beneficial to support communications for particular devices or requests in a wireless network, such as, but not limited to, machine-type communication (MTC). MTC may occur as part of the “Internet of Things,” where a low data rate may be acceptable or warranted by the use of less complex or costly data transmitters, receivers, and power sources. Where communication from a machine to a network includes a status update, sensor reading, alarm or the like, the requirement for a high data rate is less likely. Such transmissions may include large numbers of communications of relatively small packet size and require a relatively low data rate. Similar characteristics may occur for downlink transmissions from the network to the device or machine. Scheduling these types of transmissions can be inefficient due to incurring excess signaling for small packet transmissions, the latency of a scheduling request and grant procedure, and the power consumption incurred by a transmitting device or access point to deal with this excess and delay. Region 253 is a guard period (GP) separating downlink transmissions in region 251 and uplink transmissions in region 254. GP 253 can help reduce interference when switching between uplink and downlink transmissions in the network of TDD. Region 256 is a guard period, which separates downlink transmissions in region 251 from preceding uplink transmissions. It should be understood that no guard period is required before a downlink transmission that is not preceded by an uplink transmission.

[044] Figure 3A is an uplink TTI embodiment 300 in a TDD communications network. The uplink TTI 300 includes regions for downlink transmissions. As shown, the uplink TTI 300 includes a region 301 for uplink control channels, a region 302 for uplink data transmissions, a region 303 as a guard period, a region 304 for downlink transmissions of data, a region 305 for transmitting a downlink ACK/NACK message acknowledging receipt of a previous uplink data transmission, and a region 306 as another guard period. Like the downlink TDD TTI 200 in Figure 2A, regions 301-305 are divided into the time domain.

[045] Figure 3B is an uplink TTI embodiment 310 in a TDD communications network. The uplink TTI 310 includes regions for downlink transmissions. As shown, the uplink TTI 310 includes a region 311 for uplink control signals and uplink data transmissions, a region 313 as a guard period, a region 314 for downlink data transmissions and transmission of a downlink ACK/NACK message acknowledging receipt of a previous uplink data transmission, and a region 316 as another guard period. Within region 311, uplink control signals and uplink data transmissions may each use contiguous time-frequency resources, or may be interleaved in any suitable manner. In particular, uplink control signals in region 311 and uplink data transmissions in region 311 are not necessarily divided into the time domain. Similarly, within region 314, downlink data transmissions and downlink ACK/NACK messages may each use contiguous time-frequency resources, or may be interleaved in any suitable manner. In particular, downlink data transmissions in region 314 and downlink ACK/NACK messages in region 314 are not necessarily divided into the time domain. Like the downlink TDD TTI 250 in Figure 2B, regions 311-316 are divided into the time domain.

[046] Figure 3C is an uplink TTI embodiment 320 in a TDD communications network. The uplink TTI 320 includes regions for downlink transmissions. In this embodiment, downlink transmissions occur before uplink transmissions. As shown, the uplink TTI 320 includes a region 321 for uplink control channels including ACK/NACK messages acknowledging receipt of previous downlink transmissions, a region 322 for uplink data transmissions, a region 323 as a guard period, a region 324 for downlink control signals, a region 325 for downlink data transmission, and a region 326 as another guard period. Control signals in region 324 may include, for example, ACK/NACK messages acknowledging receipt of a previous uplink transmission, or signaling indicating a grant of uplink resources to region 322. Such as TTI of uplink TDD descending 200 in Figure 2A, regions 321-326 are divided into the time domain.

[047] It is considered that region 324 could be used to transmit a control signal indicating whether or not the TTI of TDD 320 is an uplink TTI or a downlink TTI.

[048] Figure 3D is an uplink TTI embodiment 330 in a TDD communications network. The uplink TTI 330 includes regions for downlink transmissions. In this embodiment, downlink transmissions occur before uplink transmissions. As shown, the uplink TTI 330 includes region 331 for uplink control signals and uplink data transmissions, region 333 as a guard period, region 334 for downlink data transmissions and signal transmissions. downlink control, and region 336 as another guard period. Control signals in region 334 may include, for example, ACK/NACK messages acknowledging receipt of a previous uplink transmission, or signaling indicating a grant of uplink resources to region 331. Within region 331, signals Uplink control systems and uplink data transmissions may each use contiguous time-frequency resources, or may be interleaved in any suitable manner. In particular, uplink control signals in region 331 and uplink data transmissions in region 331 are not necessarily divided into the time domain. Similarly, within region 334, downlink transmissions of data and downlink control signals may each use contiguous time-frequency resources, or may be interleaved in any suitable manner. In particular, downlink transmissions of data in region 334 and downlink control signals in region 334 are not necessarily divided into the time domain. Like the downlink TDD TTI 200 in Figure 2A, regions 331-336 are divided into the time domain.

[049] In the embodiments of Figures 2A, 2B, 3A, 3B, 3C and 3D, it should be understood that an ACK/NACK message may acknowledge receipt of a previous transmission in the same TTI or a previous TTI.

[050] Figure 4 is another embodiment of downlink TTI 400 in a TDD communications network. As shown, the downlink TTI 400 includes a region 401 for downlink control channels, a region 402 for downlink data transmissions, a region 403 as a guard period, a region 404 for downlink data transmissions. uplink, and a region 405 for transmitting uplink feedback information, such as an uplink ACK/NACK message. In this example, the region 401 and the region 402 are divided in the frequency domain, that is, the control signals in the region 401 and the data signals in the region 402 are transmitted during the same period of time within the downlink TTI 400 , but over different frequency resources assigned to the downlink TTI 400. For example, when the downlink TTI 400 is used to transmit signals in a frequency subband divided into multiple subcarriers for transmissions, the control signals may be transmitted on a first subcarrier of the frequency subband, and data signals can be transmitted on the other subcarriers of the frequency subband. Similarly, region 404 and region 405 are also divided into the frequency domain, which indicates that the uplink data transmissions and the uplink ACK/NACK message are transmitted during the same period of time within the uplink TTI. downlink TTI 400, but on different frequency resources assigned to the downlink TTI 400. The division of regions 401 and 402 in the frequency domain may be different from that of regions 404 and 405. For example, downlink transmissions of data in the region 402 and uplink data transmissions in region 404 are communicated on different frequency resources. Region 406 is a guard period separating downlink transmissions in regions 401-402 from a preceding uplink transmission.

[051] Figure 5 is another embodiment of uplink TTI 500 in a TDD communications network. As shown, the uplink TTI 500 includes a region 501 for uplink control channels, a region 502 for uplink data transmissions, a region 503 as a guard period, a region 504 for downlink transmissions of data, and a region 505 for transmitting a downlink ACK/NACK message. Like the downlink TTI 400 in Figure 4, regions 501 and 502 are divided into the frequency domain, and regions 504 and 505 are divided into the frequency domain. Region 506 is a guard period separating uplink transmissions in regions 501-502 from a preceding downlink transmission.

[052] As used herein, regions 204, 304, 404 and 504 are referred to as opposite data regions in a TDD TTI, and regions 205, 305, 405 and 505 are referred to as opposite return regions (or opposite ACK/NACK regions) in a TDD TTI, because transmissions in these regions are in a direction opposite to the transmission direction of the TDD TTI. These regions are also generally referred to as opposite regions in a TDD TTI. TDD TTIs with TTI structures as illustrated in Figures 2 through 5 are for illustrative purposes only, and should not be construed as limiting the scope of the claims. One of ordinary skill in the art would recognize that there are many different mechanisms or schemes for implementing data communication and/or feedback information in a TDD TTI and opposite regions in the TDD TTI.

[053] In some embodiments, transmissions in one or more opposing regions of a TDD TTI are configurable. In one embodiment, a TDD TTI of a transmission direction, i.e., downlink or uplink, may include different configurations of an opposite data region and an opposite return region, both of which are used for transmissions in a opposite direction of the TTI of TDD, that is, uplink or downlink. In one embodiment, a downlink TDD TTI may not contain any opposite data region or opposite return region. In another embodiment, the downlink TDD TTI may contain more than one opposite data region or opposite return region. In yet another embodiment, the TDD TTIs include opposing regions in different locations and with different lengths. The number, lengths, and locations of opposing regions may vary depending on factors such as traffic types, traffic latency requirements, traffic sizes, network load, as well as frame structure configurations. The different configurations of an opposing data region and an opposing return region in a TDD TTI herein are referred to as TTI switch types (or switch types), because including these opposing regions in the TDD TTI requires a transceiver to switch between a transmit mode and a receive mode. Each switching type is CHARACTERIZED by its configuration information, which may include the number of opposing data regions, the number of opposing return regions, location and duration of each such opposing region, and frequency capabilities for transmissions in these regions opposite. A switching type can indicate that there are zero, one, or more opposite regions in a TDD TTI.

[054] In some embodiments, a switching type of a TDD TTI is predefined or defined as needed, and configuration information about the switching type for the TDD TTI is signaled for communication. Signaling can be transmitted on a control channel via broadcast, multicast, or unicast. For example, when there is no data for traffic types that require a consistent low latency return, UEs can be signaled to disable opposing return regions in TDD TTIs. In another example, a base station recognizes that it requires one or more opposing regions in a TDD TTI, determines a switching type for the TDD TTI, and transmits such configuration information from the TDD TTI to a UE. In yet another example, a switching type may also be determined for a TDD TTI in response to a request from a UE. In another embodiment, each switching type corresponding to a frame structure configuration is predefined, indexed, and disseminated to all UEs. In this example, an index corresponding to a switching type configured for a TDD TTI can be transmitted, by which a UE identifies the switching type that it can use. A person of ordinary skill in the art would recognize many variations and alternatives for signaling TDD TTI configuration information with respect to switching types.

[055] As mentioned above, different frame structure configurations correspond to different combinations of frame parameters. Using different frame structure configurations to communicate traffic can provide significant spectrum flexibility, because using different combinations of SC spacings, TTI lengths, CP lengths, and symbol durations can realize performance advantages in, for example, latency and spectral efficiency. A frame structure configuration corresponding to a set of frame parameters can be assigned to a TDD TTI according to traffic types, number of UEs being served by a base station, latency requirements, or a specific request from a HUH. A switching type can also be selected for the TDD TTI according to the assigned frame configuration, a latency requirement, or a UE request. Figure 6 is a diagram of embodiment TTIs of TTD 600 configured to have different frame structure configurations and switching types for wireless communications. In this example, each frame configuration corresponds to a different set of SC spacing, CP length, and TTI length. As shown, frame structure configuration 1 is assigned to TDD TTIs 612, 614, and 616; frame structure configuration 2 is assigned to TDD TTIs 622, 624, and 626; and frame structure configuration 3 is assigned to TDD TTIs 632, 634, and 636.

[056] In some embodiments, each TDD TTI has a switching type corresponding to its assigned frame structure configuration. As described above, a switching type indicates a configuration of an opposite data region and an opposite return region in a TTI to transmit data and ACK/NACK messages in a direction opposite to the transmission direction of the TTI. Different switching types can be defined corresponding to different frame structure configurations. In this example as illustrated in Figure 6, each of the three frame structure configurations corresponds to three switching types, namely Type 0, Type 1 and Type 2. In each of the three frame structure configurations, there is no opposite region within a Type 0 TDD TTI. Type 1 and Type 2 indicate different combinations of opposite data and return regions. As shown, the TTI of TDD 612 is a type 0 TTI. The TTI of TDD 614 is a type 1 TTI, and includes an opposing return region 651 at the end of the TTI. The TDD TTI 616 is a type 2 TTI corresponding to frame structure configuration 1, and includes an opposite data region 652 and an opposite return region 653 at the end. The two opposing regions 652 and 653 are adjacent to each other in the time domain, and are herein referred to as a pair of opposing regions. A TDD TTI of this type, for example, TDD TTI 616, can be considered to be independent because downlink and uplink data, control, and feedback information exist in this TTI.

[057] Figure 6 also shows that the TTI of TDD 622 is also a TTI type 0. The TTI of TDD 624 is a TTI type 1 including an opposite data region 661 and an opposite return region 662 at the end. The TTI of TDD 626 is a type 2 TTI corresponding to frame structure configuration 2, and includes two pairs of opposing regions. As shown, a pair of opposing regions 663 and 664 are included in the middle of the TTI of TDD 626, and another pair of opposing regions 665 and 666 are included at the end of the TTI of TDD 626. The TTI of TDD 632 is a type 0 TTI The TTI of TDD 634 is a type 1 TTI corresponding to frame structure configuration 3, and the TTI of TDD 636 is a type 2 TTI corresponding to frame structure configuration 3. Figure 6 illustrates the opposite data region. adjacent and the opposite return region are arranged in a time multiplexed mode, these regions may also be in a frequency multiplexed mode.

[058] In some embodiments, different frame structure configurations may have different sets of switching types defined. For example, long TTIs, e.g. 1ms or 5ms TTIs, can have more switch types defined than those with short TTI lengths, e.g. 0.1ms or 0.125ms, to provide more options for data and information transmissions return in an opposite direction. In some embodiments, locations of opposing regions for different types of switching may be predefined. For example, for switching types with an opposite region, the opposite region can be defined to occur at the end of a TDD TTI or in the middle of the TDD TTI. In another example, for switching types with two opposing regions, one opposing region can be defined to occur at the end of a TDD TTI and the other can be defined to occur in the middle of the TDD TTI. One of ordinary skill in the art would recognize many variations for defining different switching types corresponding to different frame structure configurations and arranging opposing regions within a TDD TTI. It will be noted that for switching types with an opposite data region and an opposite return region, the two regions can be located in adjacent time periods within a TDD TTI, or in the same time period but on different power resources. frequency, to reduce the number of downlink and uplink transitions, and thus the number of guard periods. Also, although embodiments of the present disclosure illustrate TDD TTIs with an opposite data region followed by an opposite return region, it will be noted that these regions can be defined in any order. One of ordinary skill in the art would also recognize that, although not illustrated in Figure 6, a guard period would be included in a TDD TTI in any transition between downlink and uplink transmissions.

[059] Figures 7-8 illustrate tables 700 and 800 to represent frame structure configurations and their corresponding switching types in accordance with embodiments of the present disclosure. In one embodiment, a table is defined for each frame structure configuration, representing a set of corresponding switching types. As shown in Figure 7, a table 710 is used to represent four defined switching types corresponding to frame structure configuration 1. Table 720 and table 730 include seven and four switching types corresponding to frame structure configuration 2 and to frame structure configuration 3, respectively. As can be seen from Figure 7, different frame structure configurations can have different sets of switching types defined. For example, each of the three frame structure configurations has a Type 2 switching type, which, however, can be defined differently from each other. In another embodiment, a table is used to represent switching types for multiple frame structure configurations. As shown in Figure 8, table 800 includes seven switching types defined consistently for all three frame configurations 1 through 3. Whether or not a frame configuration has a defined switching type is shown by a mark in the corresponding cells from the 800 table, for example, ticked or marked as “not available” (N/A). A person of ordinary skill in the art would recognize many variations and alternatives for representing different frame structure configurations and corresponding switching types.

[060] In some embodiments, a TDD frame may carry OFDM or filtered OFDM (f-OFDM) signals communicated in TTIs according to different frame structure configurations and switching types. An f-OFDM signal can be generated by applying a pulse-shaping digital filter to an OFDM signal. Different frame structure configurations with different switching types for communications can be assigned to TTIs in different OFDM frequency sub-bands. A network controller can be used to assign frame structure configurations to the TTIs in different frequency sub-bands and select switching types for the TTIs. The network controller may send an indication to a base station indicating that the base station communicates OFDM signals on the TTIs in accordance with the assigned frame structure configurations and selected switching types. The base station may also signal frame structure configurations and switching types to UEs for communications on the TTIs.

[061] Figure 9 is a diagram of a TDD frame embodiment 900, where TTIs of different lengths are used to communicate OFDM signals. As shown, TTIs 912, 914, 916 and 918 are assigned to a frequency subband 910, and have a TTI length of T1. TTIs, such as TTI 932, assigned to a subband 930 have a TTI length of T2. TTIs assigned to a 950 subband have a TTI length of T3. TTI lengths can be integer multiples of a predefined minimum TTI length. For example, when a predefined minimum TTI length is 0.1 ms, T1 can be 0.2 ms, T2 can be 0.5 ms, and T3 can be 1 ms. As another example, when a predefined minimum TTI length is 0.125 ms, T1 may be 0.25 ms, T2 may be 0.5 ms, and T3 may be 1 ms. The TDD frame 900 is divided into time domain slots, such as the k, k+1 and k+2 slots. As shown, a TTI in the 930 subband spans one slit, and a TTI in the 950 subband spans two slits. In one embodiment, the bandwidth of a frequency subband may change over time. For example, bandwidths of the 910 subband are different during the k gap and the k+1 gap. Similarly, bandwidths of the 930 subband are different during the k gap and the k+1 gap. To simplify the description, each TTI in the TDD frame 900 of this example is a downlink TTI for downlink transmissions, and may include a portion for communicating downlink control information and a portion for communicating data. A person of ordinary skill in the art would recognize that the TDD frame 900 may include TTIs for downlink transmissions, uplink transmissions, or both.

[062] In some embodiments, one or more configurable time slots for uplink transmissions may be included in the TDD frame 900 to accommodate different uplink transmission requirements, such as low latency requirements. These configurable time slots can also provide dynamics for flexible resource allocation and spectrum utilization for uplink transmissions. As shown in Figure 900, the TDD frame 900 includes configurable time slots 921, 923, 925, 941, 943, 945, 961, 963 and 965 at the end of each slot for frequency subbands 910, 930 and 950. which are aligned across frequency sub-bands in the time domain. The configurable time slots 921, 923 and 925 are uplink TTIs. Configurable time slots 941, 943, 945, 961, 963 and 965 may be opposite data and/or feedback regions within TDD TTIs, as described above with respect to Figures 2-3. Specifically, the configurable time slot 961 divides a TTI in subband 950 into two time slots 952 and 954. Locations and duration of the configurable time slots may be predefined. In one embodiment, the lengths of the configurable time slots may be integer multiples of a length of a predefined minimum TTI, such that these configurable time slots can be aligned across the subbands in the time domain. These configurable time slots can be used to communicate uplink data or uplink feedback information, such as uplink ACK/NACK messages. For example, the configurable time slot 921 in subband 910 may be used to transmit an uplink ACK/NACK message corresponding to data transmitted in TTI 912. Retransmission of the data may be performed at a later TTI, e.g., the TTI 916 in subband 910. The uplink ACK/NACK message corresponding to the data transmitted on TTI 912 may also be transmitted in the configurable time slot 961 in subband 950. In another example, an uplink ACK/NACK message corresponding to data communicated on the TTI 914 may be transmitted in the configurable time slot 923 in subband 910. Data communicated in the TTI 914 may be retransmitted on the TTI 918 in subband 910. The configurable time slot 963 in the subband band 950 may also be used to transmit the uplink ACK/NACK message corresponding to data communicated on the TTI 914. A configurable time slot in a sub-band may be used to transmit an uplink ACK/NACK message corresponding to data of a downlink transmitted on a downlink TTI in any subband of the TDD frame 900. The configurable time slots in this example can be used to reduce HARQ round trip time (RTT) delay. As described above, a GP (not shown) is included whenever there is a transition between a downlink transmission and an uplink transmission. GPs are aligned across all frequency sub-bands in the time domain.

[063] Figure 10 is a diagram of another modality of TDD frame 1000, which carries f-OFDM signals communicated in TTIs by different frequency sub-bands. Figure 10 illustrates three frequency sub-bands 1010, 1020 and 1030. Each TTI can be a downlink or an uplink TTI. In one embodiment, a pattern of downlink and uplink TTIs of a frame, which may be referred to as a downlink/uplink TTI configuration, may be predefined for the TDD frame 1000. A TTI configuration downlink/uplink specifies a downlink:uplink TTI traffic ratio. The downlink:uplink TTI traffic ratio can be determined based on traffic types, number of UEs served in a network, latency requirements, etc. In this example, the downlink:uplink TTI ratio is 1:1. In one embodiment, the TTIs in different frequency sub-bands may have different lengths. In this example, TTIs in subband 1010 have a TTI length of 0.125 ms, such as downlink TTI 1012 and uplink TTI 1014. TTIs in subband 1020 have a TTI length of 0.25 ms. such as downlink TTI 1022 and uplink TTI 1024. TTIs in subband 1030 have a TTI length of 1 ms, such as downlink TTI 1031. As shown, downlink TTI 1031 in subband 1030 is divided into four regions 1032, 1034, 1036 and 1038 by the insertion of uplink TTIs 1041, 1043 and 1045. Each of the four regions 1032, 1034, 1036 and 1038 has a duration of 0.25 ms. The uplink TTIs 1041, 1043 and 1045 inserted into the downlink TTI can be used to communicate data or ACK/NACK return messages to meet latency requirements. Although the downlink TTI is divided into four regions 1032, 1034, 1036, and 1038, the four regions are not separate TTIs with their own control, data, and pilot channels; instead, they share the control and pilot channels, and the transmit and receive processing of the four regions are performed for the entire length of the TTI, that is, 1 ms. GPs, e.g., OFDM symbols, are inserted (not shown) to facilitate switching between downlink and uplink transmissions, and are aligned in the time domain across all frequency subbands. Figure 10 illustrates that no TTI includes any opposing feedback or data regions as illustrated above in Figures 2 through 5.

[064] Figure 11 is a diagram of another embodiment of TDD frame 1100, which carries f-OFDM signals communicated in TTIs for different frequency sub-bands 1110, 1120 and 1130. The TDD frame 1100 has a reason TTI downlink:uplink ratio of 6:2. TTIs in different frequency subbands in this example also have different lengths. TTIs in the 1110 frequency subband have a TTI length of 0.125 ms. TTIs in the 1120 frequency subband have a TTI length of 0.25 ms. TTIs in the 1130 frequency subband have a TTI length of 0.5 ms. Regions 1132 and 1134, divided by an uplink TTI 1133, form a TTI in frequency subband 1130. In one embodiment, the TDD frame 1100 may include TTIs of different switching types. For example, TTIs 1112 and 1114 in frequency subband 1110 include an opposite feedback region at the end of each corresponding TTI. TTIs 1116 and 1118 include a pair of opposing regions at the end of each corresponding TTI. TTIs 1122 and 1124 in frequency subband 1120 include an opposite feedback region located in the middle and an opposite feedback region at the end of each corresponding TTI. TTIs 1126 and 1128 include an opposite return region in the middle and a pair of opposite regions at the end. TTIs 1136 and 1138 in frequency subband 1130 include four opposing return regions and an opposing data region within a corresponding TTI. The TTI formed by regions 1132 and 1134 includes four opposing return regions. The uplink TTI 1133 includes an opposite feedback region located in the middle and another opposite feedback region located at the end. GPs are inserted (not shown) whenever there is switching between downlink and uplink transmissions, and are aligned in the time domain across multiple frequency subbands. Accordingly, the opposite return regions and the opposite data regions in TTIs of the TDD frame 1100 are also aligned across frequency subbands in the time domain. Although Figure 11 illustrates that a pair of opposing regions in a TTI, such as TTI 1126, are arranged to be adjacent to each other in the time domain, the pair of opposing regions can alternatively be assigned to different frequency resources during the same period of time.

[065] It should be understood that although oppositely directed regions of TTIs are shown to be aligned in the time domain across multiple frequency subbands, the oppositely directed regions can be used for different types of transmission in different subbands. bands. For example, oppositely directed regions of multiple subbands that are aligned in the time domain can be used for ACK/NACK feedback in a first subband, data transmissions in a second subband, and resonance reference signals. (SRS) in a third sub-band.

[066] It is further considered that, in an alternative embodiment, only the regions corresponding to control signaling may be aligned in the same direction across multiple sub-bands, and the regions corresponding to uplink or downlink data may not necessarily be are all aligned in the same direction. In such an embodiment, control signaling would not be subject to interference from opposite direction control signaling in nearby subbands, and data transmissions could be subject to other techniques to mitigate or tolerate interference due to opposite direction data communication in nearby subbands.

[067] Figure 12 is a diagram of another embodiment of TDD frame 1200, which carries f-OFDM signals communicated in TTIs in different frequency sub-bands 1210 and 1220. TDD frame 1200 has a TTI ratio downlink:uplink ratio of 6:2. TTIs in the 1210 frequency subband have a TTI length of 0.25 ms, and TTIs in the 1220 frequency subband have a TTI length of 0.5 ms. Regions 1223 and 1224, divided by an uplink TTI 1225, form a TTI in frequency subband 1220. Figure 12 also illustrates that TTIs in the TDD frame 1200 can have different switching types. For example, TTIs 1212 and 1216 have an opposite return region at the end of each corresponding TTI, TTI 1214 has a pair of opposite regions located at the end, and TTI 1218 has an opposite data region at the end. In another example, the TTI 1222 contains an opposing feedback region in the middle and a pair of opposing feedback regions at the end, the TTI formed by regions 1223 and 1224 contains two opposing feedback regions located at the middle and end of the TTI, the TTI 1225 has an opposite return region at the end, and the TTI 1226 has an opposite data region in the middle and an opposite return region at the end. In one embodiment, durations of the opposite data regions or opposite return regions may be different for different TTIs or within the same TTI. For example, the opposite data regions in TTIs 1214 and 1218 have different durations, the opposite feedback regions in TTIs 1212 and 1214 have different durations, and the opposite feedback regions in regions 1223 and 1224, which form a TTI, also have different durations. Similarly, GPs are inserted (not shown) whenever there is switching between downlink and uplink transmissions, and are aligned in the time domain across all frequency subbands.

[068] Figure 13 illustrates a diagram of a TDD frame 1300, where f-OFDM signals are communicated in TTIs over different frequency sub-bands with different subcarrier spacings. The TDD 1300 chart shows frequency subbands 1310 and 1320 with subcarrier spacing of 30kHz and 60kHz. The TDD frame 1300 has a downlink:uplink TTI ratio of 6:2, and TTIs in different f-OFDM frequency subbands have different TTI lengths. For example, the TTIs in the 1310 frequency subband have a length of 0.125 ms, and the TTIs in the 1320 frequency subband have a length of 0.25 ms. The TTIs in the TDD 1300 frame can also have different switching types. For example, TTIs 1312 and 1322 have a pair of opposite regions at the end, TTI 1314 has no opposite region, and TTIs 1316, 1324 and 1326 have an opposite return region at the end.

[069] Figure 14 illustrates a diagram of another TDD frame 1400, where f-OFDM signals are communicated in TTIs over different frequency subbands with different subcarrier spacings. The TDD frame 1400 shows frequency subbands 1410 and 1420 with subcarrier spacing of 15 kHz and 30 kHz, and the TDD frame 1400 has a downlink:uplink TTI ratio of 6:2. The TTIs in the TDD frame 1400 include TTIs having different lengths and different switching types. The TTIs in the frequency subband 1410 have a length of 0.25 ms, and the TTIs in the frequency subband 1420 have a length of 0.5 ms. TTIs 1412 and 1422 have a pair of opposite regions at the end. TTI 1414 does not have any opposite region. TTIs 1416 and 1424 have an opposite return region at the end. As shown, opposite return regions and opposite data regions included in TTIs are aligned across frequency sub-bands in the time domain. Similarly, GPs are inserted (not shown) whenever there is switching between downlink and uplink transmissions, and are aligned in the time domain across all frequency subbands. A person of ordinary skill in the art would recognize many variations and modifications for communicating OFDM signals in frame TDDs according to different frame structure and switching type configurations, where TTIs, opposing data regions and opposing return regions may be arranged. differently from those illustrated in Figures 9 to 14.

[070] As described above, different TTIs in a TDD frame can be assigned to different frame structure configurations and have different switching types. GPs can be included wherever there is a transition between downlink and uplink transmissions. The GPs included in the TDD framework need to be aligned in the time domain across different frequency sub-bands in order to prevent or reduce interference. In some embodiments, alignment of GPs may be provided by virtue of frame structure configurations having symbol durations that are integer multiples of each other. In some embodiments, alignment of GPs may also be implemented using special OFDM symbols having different durations than those specified by frame structure configurations. In one example, this can be implemented by varying the CP lengths of special OFDM symbols. Figure 15 is a diagram of a TDD 1500 board where special OFDM symbols are used to align GPs across frequency subbands. Details of TTIs and opposing return and data regions within each TTI are not shown, but it can be seen that with different combinations of these portions and different signal transmissions, the end of signal transmissions in TTIs of each sub-band of frequency may not be aligned in the time domain. The TDD frame 1500 carries f-OFDM signals communicated by two different frequency subbands 1510 and 1520 with different frame structure configurations. As described above, different frame structure configurations specify different sets of frame parameters, including bandwidth, TTI length, OFDM symbol duration, CP length, etc. In this example, the OFDM symbol duration (including CP) in the frequency subband 1510 is T1, and the OFDM symbol duration (including CP) in the frequency subband 1520 is T2. Figure 15 illustrates a region 1519 in frequency subband 1510 which may include multiple OFDM symbols (not shown) with a symbol duration of T1, and OFDM symbols 1512, 1514 and 1518 in frequency subband 1510 with a symbol duration of T1. Figure 15 also illustrates a region 1531 in frequency subband 1520 which may include multiple OFDM symbols (not shown) with a symbol duration of T2, and OFDM symbols 1522, 1524 and 1532 in frequency subband 1520 with a duration of T2. GPs 1516 and 1526 are inserted into separate downlink and uplink transmissions. In one embodiment, special OFDM symbols 1528 and 1530 having different T2 durations are placed before and after the GP 1526 in order to align the GP 1526 with the GP 1516. The special OFDM symbols 1528 and 1530 may also have different T2 durations. symbol from each other, for example, by having different CP lengths. Depending on the symbol durations of different frame structure configurations, one or more special OFDM symbols may be placed before, after, or before and after one or more GPs so that GPs are aligned across frequency subbands in the frequency domain. time.

[071] In some embodiments, different frame structure configurations and switching types may be assigned to the TTIs assigned to the same frequency resource. Figure 16 is a diagram of a TDD frame embodiment 1600 including TTIs of different frame structure configurations and switching types. TTIs 1602, 1604, and 1606 are assigned the same frame configuration, with the same TTI length as T1. These TTIs do not contain any opposite ACK/NACK or data regions. The TTI 1612 is used to communicate signals at a later time than the TTIs 1602, 1604, and 1606. As shown, the TTI 1612 is assigned a different frame structure configuration, with a TTI length of T2 and containing two pairs of regions opposite. In one embodiment, information about a frame structure configuration and a switching type defined for one or more TTIs may be broadcast over a wireless network before transmissions on such TTIs begin. Figure 16 shows two different frame structure configurations for illustrative purposes only. A person of ordinary skill in the art would recognize many variations and modifications to use different frame structure configurations and switching types for communications in TTIs over the same frequency resource.

[072] As described above, TTIs can be configured to have different frame structure configurations and TTI switching types, and used to communicate signals over different frequency sub-bands. Configuration information of a TTI can be predefined or dynamically defined, and signaled to UEs. The configuration information of a TTI may include one or more frame structure configurations, and TTI switching types, frequency subbands, and downlink/uplink TTI configuration, etc. Depending on the flexibility and types and configurations of frames used in a wireless network, it will be noted that different schemes can be defined to limit the number of bits required to signal such configuration information. Signaling can be transmitted via broadcast, multicast or unicast semi-statically or statically. In one embodiment, configuration information is semi-statically broadcast to UEs. In another embodiment, configuration information is transmitted to target UEs. In another embodiment, configuration information may be signaled over a control channel with other over-signaling messages. Depending on the types of devices and traffic being supported in a wireless network and also the load on the wireless network, TDD frames can be adaptively configured to flexibly accommodate data transmissions in TTIs using different frame structure configurations, switching types, and frequency sub-bands. The determination of how downlink and uplink transmissions are communicated in TTIs can be performed by a base station or other node or entity in a wireless network, such as a scheduling entity or a central controller associated with multiple base stations. .

[073] Figure 17 is a flowchart of an embodiment of method 1700 for wireless communications. In step 1702, a device communicates a first data transmission on a first TDD TTI of a radio frame in a first direction, and in step 1704, the device communicates a second data transmission on the first TDD TTI in a second direction. . One of the first direction and the second direction may be a transmit direction, and the other of the first direction and the second direction may be a receive direction. In one embodiment, the first direction is an uplink direction and the second direction is a downlink direction, or vice versa. The first TTI of TDD can be configured with a first frame structure configuration. The first TDD TTI may include a GP separating the first and second data transmissions. In one embodiment, the first data transmission and the second data transmission are communicated on different frequency resources. In another embodiment, the first data transmission and the second data transmission are communicated in the same frequency subband. The first data transmission or the second data transmission may also be communicated free of concession. For example, the first data transmission or the second data transmission is communicated according to a contention-based mechanism. The device may be a base station or user equipment. The device may additionally signal, to a user equipment, at least the first frame structure configuration or configuration information of the first TTI of TDD.

[074] In some embodiments, the first TTI of TDD is a downlink TTI including an uplink transmission opportunity. The uplink transmission opportunity can be viewed as an opposite data region in the downlink TTI. The downlink TTI may carry control information specifying a location, a duration, or a frequency resource of the uplink transmission opportunity in the downlink TTI. The location, duration, or frequency resource of the uplink transmission opportunity can be predefined and defined as needed. In one embodiment, the device may additionally communicate an uplink ACK/NAK message, which confirms whether or not a previously communicated downlink data transmission was successfully received. The ACK/NAK message may be communicated with an uplink data transmission on different frequency resources during the same period of time or on the same frequency resources during different periods of time. The uplink data transmission may be one of the first data transmission or the second data transmission.

[075] In some embodiments, the first TTI of TDD is an uplink TTI including a downlink transmission opportunity. The uplink TTI may carry control information specifying a location, a duration, or a frequency resource of the downlink transmission opportunity in the uplink TTI. The downlink transmission opportunity can be viewed as an opposite data region in the uplink TTI. The location, duration, or frequency resource of the downlink transmission opportunity can be predefined and defined as needed. In one embodiment, the device may additionally communicate a downlink ACK/NAK message, which confirms whether a previously communicated uplink data transmission was received successfully. The ACK/NAK message may be communicated with a downlink data transmission on different frequency resources during the same period of time or on the same frequency resources during different periods of time. The downlink data transmission may be one of the first data transmission or the second data transmission.

[076] In one embodiment, the device may additionally communicate a third data transmission on a second TDD TTI of the radio frame, where the TDD TTI is configured with a second frame structure configuration different from the first frame structure configuration. frame. The third data transmission may be communicated in a transmit direction or a receive direction. The first TTI of TDD and the second TTI of TDD can be assigned to different OFDM frequency subbands or the same OFDM frequency subband. In an example, the first TTI of TDD and the second TTI of TDD have different TTI lengths. In another example, the first and second data transmissions in the first TTI of TDD and the third data transmission in the second TTI of TDD are communicated according to different subcarrier spacings, or OFDM symbols of different lengths. In another embodiment, the device may additionally communicate a fourth data transmission in the second TTI of TDD. The third data transmission may be communicated in a transmit direction and the fourth data transmission may be communicated in a receive direction, or vice versa. In one embodiment, the second TTI of TDD may be a downlink TTI including an uplink transmission opportunity, or may be an uplink TTI including a downlink transmission opportunity. In yet another embodiment, the device may additionally communicate an ACK/NAK message in the second TTI of TDD, where the third data transmission and the ACK/NAK message travel in opposite transmission directions to each other.

[077] In some embodiments, a network controller may assign a first frame structure configuration to communicate in a first TTI of TDD in a first direction in a first frequency sub-band. The first frame structure configuration corresponds to a first set of frame parameters. The first set of frame parameters comprises a subcarrier spacing, a TTI length, an OFDM symbol duration, or a prefixed cyclic length. The network controller may be located at a base station, a higher layer network node, or any other applicable network element in a wireless network. The network controller can also select a switching type for the first TTI of TDD. The switching type indicates whether or not the first TTI of TDD includes at least one transmission opportunity to communicate in a second direction. One of the first direction and the second direction may be a transmit direction, and the other of the first direction and the second direction may be a receive direction. The network controller may then send an indication, for example, to a base station, indicating communication of OFDM signals in the first TTI of TDD in accordance with the first set of frame parameters and the selected switching type. The first frame structure configuration may be assigned according to a type of traffic data communicated in the first TTI of TDD, the number of user equipment being served by a base station, a latency requirement, or a request for a HUH. The switching type can be selected according to the first assigned frame configuration, a latency requirement, or a request from a user equipment. The network controller may also assign a second frame structure configuration to communicate on a second TDD TTI in a frequency subband that is the same or different from the first frequency subband. The second frame structure configuration corresponds to a second set of frame parameters different from the first set of frame parameters.

[078] Figure 18 is a block diagram of an embodiment of processing system 1800 for performing methods described herein, which can be installed on a host device. As shown, the processing system 1800 includes a processor 1804, a memory 1806, and interfaces 1810-1814, which may (or may not) be arranged as shown in Figure 18. The processor 1804 may be any component or collection of components adapted to perform computations and/or other related processing tasks, and memory 1806 may be any component or collection of components adapted to store programming and/or instructions for execution by processor 1804. In one embodiment, memory 1806 includes a readable medium non-transient computer. Interfaces 1810, 1812, 1814 may be any component or collection of components that allows the processing system 1800 to communicate with other devices/components and/or a user. For example, one or more of the interfaces 1810, 1812, 1814 may be adapted to communicate data, control, or management messages from the processor 1804 to requests installed on the host device and/or on a remote device. As another example, one or more of interfaces 1810, 1812, 1814 may be adapted to allow a user or user device (e.g., personal computer (PC), etc.) to interact/communicate with the processing system 1800. Processing system 1800 may include additional components not illustrated in Figure 18, such as long-term storage (e.g., non-volatile memory, etc.).

[079] In some embodiments, the processing system 1800 is included in a network device that is accessing a telecommunications network, or otherwise part thereof. In one example, the processing system 1800 is on a network-side device in a wireless or wired telecommunications network, such as a base station, a relay station, a scheduler, a controller, a gateway, a router, an application server, or any other device on the telecommunications network. In other embodiments, the processing system 1800 is on a user-owned device accessing a wireless or wired telecommunications network, such as a mobile station, a user equipment (UE), a personal computer (PC), a tablet computer, a wearable communications device (e.g., a smart watch, etc.), or any other device adapted to access a telecommunications network.

[080] In some embodiments, one or more of the interfaces 1810, 1812, 1814 connect the processing system 1800 to a transceiver adapted to transmit and receive signaling over the telecommunications network. Figure 19 is a block diagram of a transceiver 1900 adapted to transmit and receive signaling over a telecommunications network. The 1900 transceiver may be installed in a host device. As shown, the transceiver 1900 comprises a network-side interface 1902, a coupler 1904, a transmitter 1906, a receiver 1908, a signal processor 1910, and device-side interface(s) 1912. The network-side interface 1902 may include any component or collection of components adapted to transmit or receive signaling over a wireless or wired telecommunications network. Coupler 1904 may include any component or collection of components adapted to facilitate bidirectional communication over network-side interface 1902. Transmitter 1906 may include any component or collection of components (e.g., upconverter, power amplifier, etc.) adapted to convert a baseband signal into a modulated carrier signal suitable for transmission over the network-side interface 1902. Receiver 1908 may include any component or collection of components (e.g., downconverter, low-noise amplifier, etc.) adapted to convert a carrier signal received by the network side interface 1902 into a baseband signal. The signal processor 1910 may include any component or collection of components adapted to convert a baseband signal into a data signal suitable for communication over the device-side interface(s) 1912, or vice versa. The device-side interface(s) 1912 may include any component or collection of components adapted to communicate data signals between the signal processor 1910 and components within the host device (e.g., the processing system 1800, local area network (LAN) ports, etc.).

[081] Transceiver 1900 can transmit and receive signaling over any type of communications medium. In some embodiments, the transceiver 1900 transmits and receives signaling wirelessly. For example, transceiver 1900 may be a wireless transceiver adapted to communicate in accordance with a wireless telecommunications protocol, such as a cellular protocol (e.g., long term evolution (LTE), etc.), a wireless local area (WLAN) protocol (e.g., Wi-Fi, etc.), or any other type of wireless protocol (e.g., Bluetooth, near-field communication (NFC), etc.). In such embodiments, the network-side interface 1902 comprises one or more antenna/radiating elements. For example, network-side interface 1902 may include a single antenna, multiple separate antennas, or a multi-antenna array configured for multilayer communication, e.g., single input multiple output (SIMO), multiple input single output (MISO), multiple input multiple outputs (MIMO), etc. In other embodiments, the transceiver 1900 transmits and receives signaling over a wired medium, e.g., twisted pair cable, coaxial cable, optical fiber, etc. Specific processing systems and/or transceivers may utilize all of the components shown, or only a subset of the components, and levels of integration may vary from device to device.

[082] In accordance with various aspects of the invention, adaptive frame structure systems and methods for time division duplexing are disclosed.

[083] In a first aspect, the present disclosure provides a method for wireless communications, comprising: communicating, by a device, a first data transmission in a first time division duplexing (TDD) scheduling interval in a first direction, the first TDD scheduling interval being configured with a first frame structure configuration; and communicating, by the device, a second transmission of data in the first TDD scheduling interval in a second direction, one of the first direction and the second direction being a transmit direction, and the other of the first direction and the second direction being a direction to receive.

[084] In a first embodiment of the first aspect, the present disclosure provides the method further comprising signaling, to a user equipment, at least the first frame structure configuration or first TDD scheduling interval configuration information.

[085] In a second embodiment of the first aspect, the present disclosure provides the method in which the first data transmission and the second data transmission are communicated over different frequency resources.

[086] In a third embodiment of the first aspect, the present disclosure provides the method in which the first data transmission and the second data transmission are communicated over the same frequency sub-band.

[087] In a fourth embodiment of the first aspect, the present disclosure provides the method in which the device is a base station or user equipment.

[088] In a fifth embodiment of the first aspect, the present disclosure provides the method in which the first TDD scheduling interval additionally includes a guard period separating the first data transmission and the second data transmission in the time domain.

[089] In a sixth embodiment of the first aspect, the present disclosure provides the method in which the first data transmission or the second data transmission is communicated free of concession.

[090] In a further embodiment of the sixth embodiment, the present disclosure provides the method in which the first data transmission or the second data transmission is communicated according to a contention-based mechanism.

[091] In a seventh embodiment of the first aspect, the present disclosure provides the method in which the first TDD scheduling interval is a downlink scheduling interval including an uplink transmission opportunity.

[092] In a further embodiment of the seventh embodiment, the present disclosure provides the method further comprising communicating, in the downlink scheduling interval, a negative acknowledge/acknowledge (ACK/NAK) message moving in the uplink direction, to ACK/NACK message confirming whether a previous downlink data transmission was received successfully or not.

[093] In yet another additional embodiment of the seventh embodiment, the present disclosure provides the method in which the ACK/NAK message and an uplink data transmission are transmitted over different frequency resources in the downlink scheduling interval or in the same frequency sub-band during different periods of time in the downlink scheduling interval, the uplink data transmission being one of the first data transmission or the second data transmission.

[094] In an eighth embodiment of the first aspect, the present disclosure provides the method in which the first TDD scheduling interval is an uplink scheduling interval including a downlink transmission opportunity.

[095] In a further embodiment of the eighth embodiment, the present disclosure provides the method further comprising communicating, in the uplink scheduling interval, an acknowledge/don't acknowledge (ACK/NAK) message traveling in the downlink direction, to ACK/NACK message confirming that a previous uplink data transmission was received successfully.

[096] In yet another additional embodiment of the eighth embodiment, the present disclosure provides the method in which the ACK/NAK message and a downlink data transmission are transmitted over different frequency resources during the same period of time in the scheduling interval uplink, or by the same frequency sub-band during different periods of time in the uplink scheduling interval, the downlink data transmission being one of the first data transmission or the second data transmission.

[097] In a ninth embodiment of the first aspect, the present disclosure provides the method further comprising: communicating a third data transmission in a second TDD scheduling slot configured with a second frame configuration, the second frame configuration frame being different from the first frame structure configuration.

[098] In a further embodiment of the ninth embodiment, the present disclosure provides the method in which the first TDD scheduling interval and the second TDD scheduling interval have different lengths.

[099] In a further embodiment of the ninth embodiment, the present disclosure provides the method in which the first TDD scheduling interval and the second TDD scheduling interval are assigned to different frequency sub-bands.

[0100] In a further embodiment of the ninth embodiment, the present disclosure provides the method wherein the first data transmission in the first TDD scheduling interval and the third data transmission in the second TDD scheduling interval are communicated according to different subcarrier spacings, or different cyclic prefixed lengths.

[0101] In a further embodiment of the ninth embodiment, the present disclosure provides the method further comprising: communicating an accuse/don't accuse (ACK/NACK) message in the second TDD scheduling interval, the third data transmission being communicated in a transmit direction and the ACK/NAK message being communicated in a receive direction, or vice versa.

[0102] In a second aspect, the present disclosure provides a method for wireless communications, comprising: assigning, by a network controller, a first frame structure configuration to communicate in a first time division duplex scheduling interval (TDD) in a first direction by a first frequency sub-band, the first frame structure configuration corresponding to a first set of frame parameters; selecting, by the network controller, a switching type for the first TDD scheduling interval, the switching type indicating whether or not the first TDD scheduling interval includes at least one transmission opportunity to communicate in a second direction, in that one of the first direction and the second direction being a transmitting direction, and the other of the first direction and the second direction being a receiving direction; and sending an indication indicating communication of orthogonal frequency division multiplexing (OFDM) signals in the first TDD scheduling interval in accordance with the first set of frame parameters and the selected switching type.

[0103] In a first embodiment of the second aspect, the present disclosure provides the method in which the first frame structure configuration is assigned according to a data traffic type communicated in the first TDD scheduling interval, the number of user being served by a base station, a latency requirement, or a request from a user equipment.

[0104] In a second embodiment of the second aspect, the present disclosure provides the method in which the switching type is selected according to the first frame structure configuration, the latency requirement, or a request from a user equipment.

[0105] In a third embodiment of the second aspect, the present disclosure provides the method wherein the first set of frame parameters comprises a subcarrier spacing, a scheduling interval length, an OFDM symbol duration, or a cyclic length prefixed.

[0106] In a fourth embodiment of the second aspect, the present disclosure provides the method further comprising: assigning a second frame structure configuration to communicate in a second TDD scheduling slot over the first frequency sub-band, the second frame configuration frame structure corresponding to a second set of frame parameters that is different than the first set of frame parameters.

[0107] In a fifth embodiment of the second aspect, the present disclosure provides the method further comprising: assigning a second frame structure configuration to communicate in a second TDD scheduling slot in a second frequency sub-band, the second configuration of frame structure corresponding to a second set of frame parameters different from the first set of frame parameters.

[0108] In a third aspect, the present disclosure provides a method for wireless communications, comprising: communicating, by a device, a first transmission in a first time division duplexing (TDD) scheduling interval in a first direction in a first frequency sub-band; communicate, by the device, a second transmission in the first TDD scheduling interval in a second direction in the first frequency subband, one of the first direction and the second direction being a transmit direction, and the other of the first direction and the second direction being a receiving direction; communicating, by the device, a third transmission in a second TDD scheduling interval in the first direction in a second frequency sub-band; and communicating, by the device, a fourth transmission in the second TDD scheduling interval in the second direction in the second frequency subband, the second TDD scheduling interval having a duration of the first TDD scheduling interval.

[0109] In a first embodiment of the third aspect, the present disclosure provides the method in which the first TDD scheduling interval and the second TDD scheduling interval overlap in the time domain.

[0110] In a further embodiment of the first embodiment, the present disclosure provides the method in which the second transmission and the fourth transmission overlap in the time domain.

[0111] In yet another additional embodiment of the ninth embodiment, the present disclosure provides the method in which: communicating a second transmission comprises communicating a first control signaling; and communicating the fourth transmission comprises communicating a data transmission.

[0112] In a further embodiment of the first embodiment, the present disclosure provides the method in which: communicating the second transmission comprises communicating a first control signaling; and communicating the fourth transmission comprises communicating a second control signaling.

[0113] In a further embodiment of the first embodiment, the present disclosure provides the method wherein: the first control signaling and the second control signaling are different types of control signaling.

[0114] In a second embodiment of the third aspect, the present disclosure provides the method wherein: the duration of the second TDD scheduling interval is longer than the duration of the first TDD scheduling interval; and communicating the fourth transmission comprises communicating the fourth transmission in a mid-portion of the second TDD scheduling interval.

[0115] In a further embodiment of the second embodiment, the present disclosure provides the method further comprising communicating a fifth transmission at one end of the second TDD scheduling slot in the second direction in the second frequency sub-band.

[0116] In a third embodiment of the third aspect, the present disclosure provides the method in which the duration of the first TDD scheduling interval is determined based on a subcarrier spacing of the first TDD scheduling interval, and the duration of the second TDD scheduling interval is determined based on a subcarrier spacing of the second TDD scheduling interval.

[0117] In a fourth aspect, the present disclosure provides a method of performing wireless communication, comprising: in a first time division duplexing (TDD) scheduling interval, receiving a data transmission; and in the first TDD scheduling interval, transmit an acknowledge (ACK).

[0118] In a first embodiment of the fourth aspect, the present disclosure provides the method in which the ACK acknowledges receipt of data transmission.

Claims (20)

1. Method for wireless communications, CHARACTERIZED by the fact that it comprises: receiving, by a user equipment (UE), signaling to indicate a time division duplexing (TDD) frame structure configuration from a station base, the TDD frame configuration corresponding to a transmission time interval (TTI) of 0.125 ms, 0.25 ms, or 0.5 ms, the TDD frame configuration comprising downlink transmissions , uplink transmissions, and two switching points within the TTI, each switching point of the two switching points being a transmission direction transition between a downlink transmission of the downlink transmissions within the TTI and an uplink transmission uplink transmissions within the TTI, and communicating, by the UE, at least one of the downlink and uplink transmissions within the TTI in accordance with the TDD frame structure configuration. 2. Method, according to claim 1, CHARACTERIZED by the fact that the communication comprises: receiving, by the UE, a first downlink transmission in a TDD TTI, the TDD TTI being configured with the frame structure configuration of TDD; transmitting, by the UE, a first uplink transmission in the TDD TTI; receiving, by the UE, a second downlink transmission in the TDD TTI; and transmitting, by the UE, a second uplink transmission in the TDD TTI. 3. Method according to claim 2, CHARACTERIZED by the fact that the at least one of the first uplink transmission or the second uplink transmission includes an acknowledgment or negative acknowledgment (ACK/NACK) message. 4. Method, according to claim 2, CHARACTERIZED by the fact that the TDD frame structure configuration further comprises a guard period to separate the first downlink transmission and the first uplink transmission in the time domain. 5. Method according to claim 2, CHARACTERIZED by the fact that the TDD frame structure configuration further comprises a guard period for separating the second downlink transmission and the second uplink transmission in the time domain. 6. User equipment (UE), CHARACTERIZED by the fact that it comprises: a processor; and a non-transitory computer readable storage medium storing programming for execution by the processor, the programming comprising instructions for: receiving signaling to indicate a time division duplexing (TDD) frame structure configuration from a base station, the TDD frame structure configuration corresponding to a transmission time interval (TTI) of 0.125 ms, 0.25 ms, or 0.5 ms, the TDD frame structure configuration comprising downlink transmissions, transmissions uplink transmission, and two switching points within the TTI, each switching point of the two switching points being a transmission direction transition between a downlink transmission of the downlink transmissions within the TTI and an uplink transmission of the uplink transmissions within the TTI; and communicating at least one of downlink and uplink transmissions within the TTI in accordance with the TDD frame structure configuration. 7. UE, according to claim 6, CHARACTERIZED by the fact that the instructions to communicate comprise instructions to: receive a first downlink transmission in a TDD TTI, the TDD TTI being configured with the frame structure configuration of TDD; transmitting a first uplink transmission in the TTI of TDD; receiving a second downlink transmission in the TTI of TDD; and transmitting a second uplink transmission in the TDD TTI. 8. UE, according to claim 7, CHARACTERIZED by the fact that the at least one of the first uplink transmission or the second uplink transmission includes an acknowledgment or negative acknowledgment message (ACK/NACK). 9. UE, according to claim 7, CHARACTERIZED by the fact that the TDD frame structure configuration further comprises a guard period to separate the first downlink transmission and the first uplink transmission in the time domain. 10. UE, according to claim 7, CHARACTERIZED by the fact that the TDD structure configuration further comprises a guard period to separate the second downlink transmission and the second uplink transmission in the time domain. 11. Method for wireless communications, CHARACTERIZED by the fact that it comprises: transmitting, by a base station, signaling to indicate a time division duplexing (TDD) frame structure configuration to a user equipment (UE), the TDD frame structure configuration corresponding to a transmission time interval (TTI) of 0.125 ms, 0.25 ms, or 0.5 ms, the TDD frame structure configuration comprising downlink transmissions, uplink transmission and two switching points within the TTI, each switching point of the two switching points being a transmission direction transition between a downlink transmission of the downlink transmissions within the TTI and an uplink transmission of the uplink within the TTI; and communicating, by the base station, at least one of downlink and uplink transmissions within the TTI in accordance with the TDD frame structure configuration. 12. Method according to claim 11, CHARACTERIZED by the fact that the communication comprises: transmitting, by the base station, a first downlink transmission in a TDD TTI, the TDD TTI being configured with the structure configuration TDD framework; receiving, by the base station, a first uplink transmission in the TTI of TDD; transmitting, by the base station, a second downlink transmission in the TDD TTI; and receiving, by the base station, a second uplink transmission in the TDD TTI. 13. Method according to claim 12, CHARACTERIZED by the fact that at least one of the first uplink transmission or the second uplink transmission includes an acknowledgment or negative acknowledgment (ACK/NACK) message. 14. The method of claim 12, wherein the TDD frame structure configuration further comprises a guard period for separating the first downlink transmission and the first uplink transmission in the time domain. 15. The method of claim 12, wherein the TDD frame structure configuration further comprises a guard period for separating the second downlink transmission and the second uplink transmission in the time domain. 16. Base station, CHARACTERIZED by the fact that it comprises: a processor; and a non-transitory computer readable storage medium storing programming for execution by the processor, the programming comprising instructions for: transmitting signaling to indicate a time division duplexing (TDD) frame structure configuration to a user equipment (UE) , the TDD frame configuration corresponding to a transmission time interval (TTI) of 0.125 ms, 0.25 ms, or 0.5 ms, or the TDD frame configuration comprising downlink transmissions , uplink transmissions, and two switching points within the TTI, each switching point of the two switching points being a transmission direction transition between a downlink transmission of the downlink transmissions within the TTI and an uplink transmission uplink transmissions within the TTI; and communicating at least one of downlink and uplink transmissions within the TTI in accordance with the TDD frame structure configuration. 17. Base station according to claim 16, CHARACTERIZED by the fact that the instructions to communicate comprise instructions to: transmit a first downlink transmission in a TDD TI the TDD TTI being configured with the structure configuration of TDD framework; receiving a first uplink transmission in the TTI of TDD; transmitting a second downlink transmission in the TTI of TDD; and receiving a second uplink transmission on the TTI of TDD. 18. Base station according to claim 17, CHARACTERIZED by the fact that at least one of the first uplink transmission or the second uplink transmission includes an acknowledgment or negative acknowledgment (ACK/NACK) message. 19. The base station of claim 17, wherein the TDD frame structure configuration further comprises a guard period for separating the first downlink transmission and the first uplink transmission in the domain. time. 20. The base station of claim 17, wherein the TDD frame structure configuration further comprises a guard period for separating the second downlink transmission and the second uplink transmission in the time.