Uplink Design for Narrowband LTE (NB-LTE)

Abstract

Aspects of the present disclosure provide techniques for wireless communications by a base station, and more particularly, relate to uplink designs for narrowband LTE (NB‑LTE). An example method generally includes allocating uplink resources to one or more first type user equipment (UE) communicating with the base station on a first frequency band narrower than a second frequency band used to communicate with a second type of user equipment (UE), wherein the uplink resources may be allocated with the same or different symbol duration and the same or different time granularity as the uplink resources allocated to the second type of UE and with a single subcarrier allocated to the first type of UE, and receiving an uplink transmission from the first type of UE on the allocated resources.

Description

[0001] This application is a divisional application of the Chinese patent application with application number 201680050712.1, filed on July 14, 2016, and invention name “Uplink design of narrowband LTE (NB-LTE)”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of U.S. Provisional Patent Application S / N. 62 / 214,165 filed on September 3, 2015, U.S. Provisional Patent Application S / N. 62 / 232,634 filed on September 25, 2015, and U.S. Patent Application No. 15 / 209,505 filed on July 13, 2016, all of which have been assigned to the assignee of this application and are incorporated herein by reference in their entirety. background

[0004] I. Field

[0005] Certain aspects of the present disclosure relate generally to wireless communications and, more particularly, to uplink resources used by a UE operating on a narrowband relative to other UEs.

[0006] II. Background Technology

[0007] Wireless communication systems are widely deployed to provide various types of communication content such as voice, data, etc. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth and transmit power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, third generation partnership project (3GPP) long term evolution (LTE) / LTE-Advanced systems, and orthogonal frequency division multiple access (OFDMA) systems.

[0008] In general, a wireless multiple access communication system can support the communication of multiple wireless terminals simultaneously. Each terminal communicates with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from the base station to the terminal, while the reverse link (or uplink) refers to the communication link from the terminal to the base station. Such communication links can be established via single-input single-output, multiple-input single-output, or multiple-input multiple-output (MIMO) systems.

[0009] A wireless communication network may include several base stations that can support communication of several wireless devices. The wireless devices may include user equipment (UE). Some examples of UE may include cellular phones, smart phones, personal digital assistants (PDAs), wireless modems, handheld devices, tablet devices, laptop computers, netbooks, smartbooks, ultrabooks, etc. Some UEs may be considered machine type communication (MTC) UEs, which may include remote devices that can communicate with a base station, another remote device, or some other entity, such as sensors, meters, location tags, etc. Machine type communication (MTC) may refer to communication involving at least one remote device at at least one end of the communication, and may include a form of data communication involving one or more entities that do not necessarily require human interaction. MTC UEs may include UEs that are capable of MTC communication with an MTC server and / or other MTC devices via, for example, a public land mobile network (PLMN).

[0010] Overview

[0011] Certain aspects of the present disclosure provide a method for wireless communication by a base station (BS). The method generally includes allocating uplink resources to one or more first-type UEs communicating with the BS on a first frequency band narrower than a second frequency band used to communicate with a second-type user equipment (UE), wherein the uplink resources are allocated in a narrowband subframe structure having a symbol duration determined at least in part based on communication characteristics between the BS and the second-type UE using the second frequency band; and receiving uplink transmissions from the first-type UE on the allocated resources.

[0012] Certain aspects of the present disclosure provide an apparatus for wireless communication by a base station. The apparatus generally includes a processing system configured to allocate uplink resources to one or more first-type user equipment (UE) communicating with the base station on a first frequency band narrower than a second frequency band used to communicate with a second-type user equipment (UE), wherein the uplink resources are allocated in a narrowband subframe structure having a symbol duration determined at least in part based on communication characteristics between the base station and the second-type UE using the second frequency band; and a receiver configured to receive uplink transmissions from the first-type UE on the allocated resources.

[0013] Certain aspects of the present disclosure provide an apparatus for wireless communication by a base station. The apparatus generally includes a device for allocating uplink resources to one or more first-type user equipment (UE) communicating with the base station on a first frequency band narrower than a second frequency band used to communicate with a second-type user equipment (UE), wherein the uplink resources are allocated in a narrowband subframe structure having a symbol duration determined at least in part based on communication characteristics between the base station and the second-type UE using the second frequency band; and a device for receiving uplink transmissions from the first-type UE on the allocated resources.

[0014] Certain aspects of the present disclosure provide a computer-readable medium for wireless communication by a base station. The computer-readable medium generally has instructions stored thereon, which can be executed by one or more processors to allocate uplink resources to one or more first-type UEs communicating with the base station on a first frequency band narrower than a second frequency band used to communicate with a second-type user equipment (UE), wherein the uplink resources are allocated in a narrowband subframe structure having a symbol duration determined at least in part based on communication characteristics between the base station and the second-type UE using the second frequency band; and receive uplink transmissions from the first-type UE on the allocated resources.

[0015] Certain aspects of the present disclosure provide a method for wireless communication by a user equipment (UE). The method generally includes receiving from a base station (BS) an uplink resource allocation for communicating with the base station on a first frequency band narrower than a second frequency band used by a second type UE to communicate with the base station, wherein the uplink resource is allocated in a narrowband subframe structure having a symbol duration determined at least in part based on communication characteristics between the BS and the second type UE using the second frequency band; and performing uplink transmission on the allocated resources.

[0016] Certain aspects of the present disclosure provide an apparatus for wireless communication by a user equipment (UE). The apparatus generally includes a receiver configured to receive from a base station (BS) an uplink resource allocation for communicating with the base station on a first frequency band narrower than a second frequency band used by a second type UE to communicate with the base station, wherein the uplink resource is allocated in a narrowband subframe structure having a symbol duration determined at least in part based on communication characteristics between the BS and the second type UE using the second frequency band; and a transmitter configured to perform uplink transmission on the allocated resources.

[0017] Certain aspects of the present disclosure provide an apparatus for wireless communication by a user equipment (UE). The apparatus generally includes a device for receiving an uplink resource allocation for communicating with the base station on a first frequency band narrower than a second frequency band used by a second type UE to communicate with the base station, wherein the uplink resource is allocated in a narrowband subframe structure having a symbol duration determined at least in part based on communication characteristics between the BS and the second type UE using the second frequency band; and a device for performing uplink transmission on the allocated resources.

[0018] Certain aspects of the present disclosure provide a computer-readable medium for wireless communication by a user equipment (UE). The computer-readable medium generally includes instructions stored thereon, which can be executed by one or more processors to receive from a base station (BS) an uplink resource allocation for communicating with the base station on a first frequency band narrower than a second frequency band used by a second type of UE to communicate with the base station, wherein the uplink resource is allocated in a narrowband subframe structure having a symbol duration determined at least in part based on communication characteristics between the BS and the second type of UE using the second frequency band; and perform uplink transmission on the allocated resources.

[0019] Certain aspects of the present disclosure provide a method for wireless communication by a base station (BS). The method generally includes allocating uplink resources to one or more first-type UEs communicating with the BS on a first frequency band narrower than a second frequency band used to communicate with a second-type user equipment (UE), wherein the uplink resources are allocated with the same symbol duration and the same time granularity as the uplink resources allocated to the second-type UE and have a single subcarrier allocated to the first-type UE; and receiving an uplink transmission from the first-type UE on the allocated resources.

[0020] Certain aspects of the present disclosure provide an apparatus for wireless communication by a base station (BS). The apparatus generally includes a processing system configured to allocate uplink resources to one or more first-type UEs communicating with the BS on a first frequency band narrower than a second frequency band used to communicate with a second-type user equipment (UE), wherein the uplink resources are allocated with the same symbol duration and the same time granularity as the uplink resources allocated to the second-type UE and have a single subcarrier allocated to the first-type UE; and a receiver configured to receive an uplink transmission from the first-type UE on the allocated resources.

[0021] Certain aspects of the present disclosure provide an apparatus for wireless communication by a base station (BS). The apparatus generally includes a device for allocating uplink resources to one or more first-type UEs communicating with the BS on a first frequency band narrower than a second frequency band used to communicate with second-type user equipment (UE), wherein the uplink resources are allocated with the same symbol duration and the same time granularity as the uplink resources allocated to the second-type UE and have a single subcarrier allocated to the first-type UE; and a device for receiving an uplink transmission from the first-type UE on the allocated resources.

[0022] Certain aspects of the present disclosure provide a computer-readable medium for wireless communication by a base station (BS). The computer-readable medium generally includes instructions stored thereon, which can be executed by one or more processors to allocate uplink resources to one or more first-type UEs communicating with the BS on a first frequency band narrower than a second frequency band used to communicate with a second-type user equipment (UE), wherein the uplink resources are allocated with the same symbol duration and the same time granularity as the uplink resources allocated to the second-type UE and have a single subcarrier allocated to the first-type UE; and receive uplink transmissions from the first-type UE on the allocated resources.

[0023] Certain aspects of the present disclosure provide a method for wireless communication by a first type of user equipment (UE). The method generally includes receiving from a base station an uplink resource allocation for communicating with the base station on a first frequency band narrower than a second frequency band used by a second type of UE to communicate with the base station, wherein the allocated resources have the same symbol duration and the same time granularity as the uplink resources allocated to the second type of UE, and have a single subcarrier allocated to the first type of UE; and performing an uplink transmission on the allocated resources.

[0024] Certain aspects of the present disclosure provide an apparatus for wireless communication by a first type of user equipment (UE). The apparatus generally includes a receiver configured to receive from a base station an uplink resource allocation for communicating with the base station on a first frequency band narrower than a second frequency band used by a second type of UE to communicate with the base station, wherein the allocated resources have the same symbol duration and the same time granularity as the uplink resources allocated to the second type of UE, and have a single subcarrier allocated to the first type of UE; and a transmitter configured to perform uplink transmission on the allocated resources.

[0025] Certain aspects of the present disclosure provide an apparatus for wireless communication by a first type of user equipment (UE). The apparatus generally includes means for receiving from a base station an uplink resource allocation for communicating with the base station on a first frequency band narrower than a second frequency band used by a second type of UE to communicate with the base station, wherein the allocated resources have the same symbol duration and the same time granularity as the uplink resources allocated to the second type of UE, and have a single subcarrier allocated to the first type of UE; and means for performing uplink transmission on the allocated resources.

[0026] Certain aspects of the present disclosure provide a computer-readable medium for wireless communication by a first type of user equipment (UE). The computer-readable medium generally includes instructions stored thereon, which can be executed by one or more processors to receive from a base station an uplink resource allocation for communicating with the base station on a first frequency band narrower than a second frequency band used by a second type of UE to communicate with the base station, wherein the allocated resources have the same symbol duration and the same time granularity as the uplink resources allocated to the second type of UE, and have a single subcarrier allocated to the first type of UE; and perform uplink transmission on the allocated resources.

[0027] Certain aspects of the present disclosure provide a method for wireless communication by a base station (BS). The method generally includes allocating uplink resources to one or more first-type UEs communicating with the BS on a first frequency band narrower than a second frequency band used to communicate with a second-type user equipment (UE), wherein the uplink resources are allocated in a narrowband subframe structure with an increased symbol duration and a narrower subcarrier spacing relative to the uplink resources allocated to the second-type UE, and wherein the narrowband subframe structure includes at least two time slots, each of which has the same duration as the subframe structure used to communicate with the second-type UE; and receiving an uplink transmission from the first-type UE on the allocated resources.

[0028] Certain aspects of the present disclosure provide an apparatus for wireless communication by a base station (BS). The apparatus generally includes a processing system configured to allocate uplink resources to one or more first type UEs communicating with the BS on a first frequency band narrower than a second frequency band used to communicate with a second type of user equipment (UE), wherein the uplink resources are allocated in a narrowband subframe structure having an increased symbol duration and a narrower subcarrier spacing relative to the uplink resources allocated to the second type UE, and wherein the narrowband subframe structure includes at least two time slots, each of which has the same duration as the subframe structure used to communicate with the second type UE; and a receiver configured to receive an uplink transmission from the first type UE on the allocated resources.

[0029] Certain aspects of the present disclosure provide an apparatus for wireless communication by a base station (BS). The apparatus generally includes a device for allocating uplink resources to one or more first-type UEs communicating with the BS on a first frequency band narrower than a second frequency band used to communicate with a second-type user equipment (UE), wherein the uplink resources are allocated in a narrowband subframe structure having an increased symbol duration and a narrower subcarrier spacing relative to the uplink resources allocated to the second-type UE, and wherein the narrowband subframe structure includes at least two time slots, each of which has the same duration as the subframe structure used to communicate with the second-type UE; and a device for receiving an uplink transmission from the first-type UE on the allocated resources.

[0030] Certain aspects of the present disclosure provide a computer-readable medium for wireless communication by a base station (BS). The computer-readable medium generally includes instructions stored thereon, which can be executed by one or more processors to allocate uplink resources to one or more first-type UEs communicating with the BS on a first frequency band narrower than a second frequency band used to communicate with a second-type user equipment (UE), wherein the uplink resources are allocated in a narrowband subframe structure with an increased symbol duration and a narrower subcarrier spacing relative to the uplink resources allocated to the second-type UE, and wherein the narrowband subframe structure includes at least two time slots, each of which has the same duration as the subframe structure used to communicate with the second-type UE; and receiving an uplink transmission from the first-type UE on the allocated resources.

[0031] Certain aspects of the present disclosure provide a method for wireless communication by a first type of user equipment (UE). The method generally includes receiving from a base station an uplink resource allocation for communicating with the base station on a first frequency band narrower than a second frequency band used by a second type of UE to communicate with the base station, wherein the uplink resource is allocated in a narrowband subframe structure having an increased symbol duration and a narrower subcarrier spacing relative to the uplink resource allocated to the second type of UE, and wherein the narrowband subframe structure includes at least two time slots, each of which has the same duration as the subframe structure used to communicate with the second type of UE; and performing uplink transmission on the allocated resources.

[0032] Certain aspects of the present disclosure provide an apparatus for wireless communication by a first type of user equipment (UE). The apparatus generally includes a receiver configured to receive from a base station an uplink resource allocation for communicating with the base station on a first frequency band narrower than a second frequency band used by a second type of UE to communicate with the base station, wherein the uplink resource is allocated in a narrowband subframe structure having an increased symbol duration and a narrower subcarrier spacing relative to the uplink resource allocated to the second type of UE, and wherein the narrowband subframe structure includes at least two time slots, each of which has the same duration as the subframe structure used to communicate with the second type of UE; and a transmitter configured to perform uplink transmission on the allocated resources.

[0033] Certain aspects of the present disclosure provide an apparatus for wireless communication by a first type of user equipment (UE). The apparatus generally includes a device for receiving from a base station an uplink resource allocation for communicating with the base station on a first frequency band narrower than a second frequency band used by a second type of UE to communicate with the base station, wherein the uplink resource is allocated in a narrowband subframe structure having an increased symbol duration and a narrower subcarrier spacing relative to the uplink resource allocated to the second type of UE, and wherein the narrowband subframe structure includes at least two time slots, each of which has the same duration as the subframe structure used to communicate with the second type of UE; and a device for performing uplink transmission on the allocated resources.

[0034] Certain aspects of the present disclosure provide a computer-readable medium for wireless communication by a first type of user equipment (UE). The computer-readable medium generally includes instructions stored thereon, which can be executed by one or more processors to receive from a base station an uplink resource allocation for communicating with the base station on a first frequency band narrower than a second frequency band used by a second type of UE to communicate with the base station, wherein the uplink resource is allocated in a narrowband subframe structure having an increased symbol duration and a narrower subcarrier spacing relative to the uplink resource allocated to the second type of UE, and wherein the narrowband subframe structure includes at least two time slots, each of which has the same duration as the subframe structure used to communicate with the second type of UE; and performing uplink transmission on the allocated resources.

[0035] Certain aspects of the present disclosure provide a method for wireless communication by a base station (BS). The method generally includes allocating uplink resources to one or more first-type UEs communicating with the BS on a first frequency band narrower than a second frequency band used to communicate with a second-type user equipment (UE), wherein the uplink resources are allocated in a narrowband subframe structure with an increased symbol duration relative to the uplink resources allocated to the second-type UE, and wherein the narrowband subframe structure includes at least two symbols and has the same duration as the subframe structure used to communicate with the second-type UE; and receiving an uplink transmission from the first-type UE on the allocated resources.

[0036] Certain aspects of the present disclosure provide an apparatus for wireless communication by a base station (BS). The apparatus generally includes a processing system configured to allocate uplink resources to one or more first-type UEs communicating with the BS on a first frequency band narrower than a second frequency band used to communicate with a second-type user equipment (UE), wherein the uplink resources are allocated in a narrowband subframe structure with an increased symbol duration relative to the uplink resources allocated to the second-type UE, and wherein the narrowband subframe structure includes at least two symbols and has the same duration as the subframe structure used to communicate with the second-type UE; and a receiver configured to receive an uplink transmission from the first-type UE on the allocated resources.

[0037] Certain aspects of the present disclosure provide an apparatus for wireless communication by a base station (BS). The apparatus generally includes a device for allocating uplink resources to one or more first-type UEs communicating with the BS on a first frequency band narrower than a second frequency band used to communicate with a second-type user equipment (UE), wherein the uplink resources are allocated in a narrowband subframe structure with an increased symbol duration relative to the uplink resources allocated to the second-type UE, and wherein the narrowband subframe structure includes at least two symbols and has the same duration as the subframe structure used to communicate with the second-type UE; and a device for receiving an uplink transmission from the first-type UE on the allocated resources.

[0038] Certain aspects of the present disclosure provide a computer-readable medium for wireless communication by a base station (BS). The computer-readable medium generally includes instructions stored thereon, which can be executed by one or more processors to allocate uplink resources to one or more first-type UEs communicating with the BS on a first frequency band narrower than a second frequency band used to communicate with a second-type user equipment (UE), wherein the uplink resources are allocated in a narrowband subframe structure with an increased symbol duration relative to the uplink resources allocated to the second-type UE, and wherein the narrowband subframe structure includes at least two symbols and has the same duration as the subframe structure used to communicate with the second-type UE; and receive uplink transmissions from the first-type UE on the allocated resources.

[0039] Certain aspects of the present disclosure provide a method for wireless communication by a first type of user equipment (UE). The method generally includes receiving from a base station an uplink resource allocation for communicating with the base station on a first frequency band narrower than a second frequency band used by a second type of UE to communicate with the base station, wherein the uplink resource is allocated in a narrowband subframe structure having an increased symbol duration relative to the uplink resource allocated to the second type of UE, and wherein the narrowband subframe structure includes at least two symbols and has the same duration as the subframe structure used to communicate with the second type of UE; and performing an uplink transmission on the allocated resources.

[0040] Certain aspects of the present disclosure provide an apparatus for wireless communication by a first type of user equipment (UE). The apparatus generally includes a receiver configured to receive from a base station an uplink resource allocation for communicating with the base station on a first frequency band narrower than a second frequency band used by a second type of UE to communicate with the base station, wherein the uplink resource is allocated in a narrowband subframe structure having an increased symbol duration relative to the uplink resource allocated to the second type of UE, and wherein the narrowband subframe structure includes at least two symbols and has the same duration as the subframe structure used to communicate with the second type of UE; and a transmitter configured to perform uplink transmission on the allocated resources.

[0041] Certain aspects of the present disclosure provide an apparatus for wireless communication by a first type of user equipment (UE). The apparatus generally includes a device for receiving from a base station an uplink resource allocation for communicating with the base station on a first frequency band narrower than a second frequency band used by a second type of UE to communicate with the base station, wherein the uplink resource is allocated in a narrowband subframe structure having an increased symbol duration relative to the uplink resource allocated to the second type of UE, and wherein the narrowband subframe structure includes at least two symbols and has the same duration as the subframe structure used to communicate with the second type of UE; and a device for performing uplink transmission on the allocated resources.

[0042] Certain aspects of the present disclosure provide a computer-readable medium for wireless communication by a first type of user equipment (UE). The computer-readable medium generally includes instructions stored thereon, which can be executed by one or more processors to receive from a base station an uplink resource allocation for communicating with the base station on a first frequency band narrower than a second frequency band used by a second type of UE to communicate with the base station, wherein the uplink resource is allocated in a narrowband subframe structure with an increased symbol duration relative to the uplink resource allocated to the second type of UE, and wherein the narrowband subframe structure includes at least two symbols and has the same duration as the subframe structure used to communicate with the second type of UE; and perform uplink transmission on the allocated resources.

[0043] Certain aspects of the present disclosure provide a method for wireless communication by a base station (BS). The method generally includes allocating uplink resources to one or more first-type UEs communicating with the BS on a first frequency band narrower than a second frequency band used to communicate with a second-type user equipment (UE), wherein the uplink resources are allocated in a narrowband subframe structure with an increased symbol duration relative to the uplink resources allocated to the second-type UE, and wherein the symbols in the narrowband subframe structure are aligned with a boundary of a set of multiple subframe structures used to communicate with the second-type UE; and receiving an uplink transmission from the first-type UE on the allocated resources.

[0044] Certain aspects of the present disclosure provide an apparatus for wireless communication by a base station (BS). The apparatus generally includes a processing system configured to allocate uplink resources to one or more first-type UEs communicating with the BS on a first frequency band narrower than a second frequency band used to communicate with a second-type user equipment (UE), wherein the uplink resources are allocated in a narrowband subframe structure with an increased symbol duration relative to the uplink resources allocated to the second-type UE, and wherein the symbols in the narrowband subframe structure are aligned with a boundary of a set of multiple subframe structures used to communicate with the second-type UE; and a receiver configured to receive an uplink transmission from the first-type UE on the allocated resources.

[0045] Certain aspects of the present disclosure provide an apparatus for wireless communication by a base station (BS). The apparatus generally includes a device for allocating uplink resources to one or more first-type UEs communicating with the BS on a first frequency band narrower than a second frequency band used to communicate with a second-type user equipment (UE), wherein the uplink resources are allocated in a narrowband subframe structure with an increased symbol duration relative to the uplink resources allocated to the second-type UE, and wherein the symbols in the narrowband subframe structure are aligned with a boundary of a set of multiple subframe structures used to communicate with the second-type UE; and a device for receiving an uplink transmission from the first-type UE on the allocated resources.

[0046] Certain aspects of the present disclosure provide a computer-readable medium for wireless communication by a base station (BS). The computer-readable medium generally includes instructions stored thereon, which can be executed by one or more processors to allocate uplink resources to one or more first-type UEs communicating with the BS on a first frequency band narrower than a second frequency band used to communicate with a second-type user equipment (UE), wherein the uplink resources are allocated in a narrowband subframe structure with an increased symbol duration relative to the uplink resources allocated to the second-type UE, and wherein the symbols in the narrowband subframe structure are aligned with a boundary of a set of multiple subframe structures used to communicate with the second-type UE; and receive uplink transmissions from the first-type UE on the allocated resources.

[0047] Certain aspects of the present disclosure provide a method for wireless communication by a first type of user equipment (UE). The method generally includes receiving from a base station an allocation of uplink resources for communicating with the base station on a first frequency band narrower than a second frequency band used by a second type of UE to communicate with the base station, wherein the uplink resources are allocated in a narrowband subframe structure having an increased symbol duration relative to the uplink resources allocated to the second type of UE, and wherein the symbols in the narrowband subframe structure are aligned with a boundary of a set of multiple subframe structures used to communicate with the second type of UE; and performing uplink transmission on the allocated resources.

[0048] Certain aspects of the present disclosure provide an apparatus for wireless communication by a first type of user equipment (UE). The method generally includes a receiver configured to receive from a base station an allocation of uplink resources for communicating with the base station on a first frequency band narrower than a second frequency band used by a second type of UE to communicate with the base station, wherein the uplink resources are allocated in a narrowband subframe structure having an increased symbol duration relative to the uplink resources allocated to the second type of UE, and wherein the symbols in the narrowband subframe structure are aligned with a boundary of a set of multiple subframe structures used to communicate with the second type of UE; and a transmitter configured to perform uplink transmission on the allocated resources.

[0049] Certain aspects of the present disclosure provide an apparatus for wireless communication by a first type of user equipment (UE). The apparatus generally includes a device for receiving from a base station an allocation of uplink resources for communicating with the base station on a first frequency band narrower than a second frequency band used by a second type of UE to communicate with the base station, wherein the uplink resources are allocated in a narrowband subframe structure having an increased symbol duration relative to the uplink resources allocated to the second type of UE, and wherein the symbols in the narrowband subframe structure are aligned with a boundary of a set of multiple subframe structures used to communicate with the second type of UE; and a device for performing uplink transmission on the allocated resources.

[0050] Certain aspects of the present disclosure provide a computer-readable medium for wireless communication by a first type of user equipment (UE). The computer-readable medium generally includes instructions stored thereon, which can be executed by one or more processors to receive from a base station an allocation of uplink resources for communicating with the base station on a first frequency band narrower than a second frequency band used by a second type of UE to communicate with the base station, wherein the uplink resources are allocated in a narrowband subframe structure with an increased symbol duration relative to the uplink resources allocated to the second type of UE, and wherein the symbols in the narrowband subframe structure are aligned with a boundary of a set of multiple subframe structures used to communicate with the second type of UE; and perform uplink transmission on the allocated resources.

[0051] Numerous other aspects are provided including methods, apparatus, systems, computer program products, and processing systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 is a block diagram conceptually illustrating an example of a wireless communication network in accordance with certain aspects of the present disclosure.

[0053] Figure 2 Shown is a block diagram conceptually illustrating an example of a base station in communication with a user equipment (UE) in a wireless communication network in accordance with certain aspects of the present disclosure.

[0054] Figure 3 An exemplary frame structure for FDD in LTE is shown.

[0055] Figure 4 Two exemplary subframe formats with normal cyclic prefix are shown.

[0056] Figure 5 An example of a narrowband deployment within a larger system bandwidth is illustrated in accordance with certain aspects of the present disclosure.

[0057] Figure 6 Illustrated are example operations that may be performed by a base station to communicate with a UE over a narrow frequency band relative to a second frequency band, in accordance with certain aspects of the present disclosure.

[0058] Figure 7 Illustrated are example operations that may be performed by a user equipment (UE) to communicate with a base station over a narrow frequency band relative to a second frequency band, in accordance with certain aspects of the present disclosure.

[0059] Figure 8 An example narrowband subframe structure is illustrated in accordance with certain aspects of the present disclosure.

[0060] Fig. 9 Illustrated are example operations that may be performed by a base station to communicate with a UE over a narrow frequency band relative to a second frequency band, in accordance with certain aspects of the present disclosure.

[0061] Fig.10 Illustrated are example operations that may be performed by a user equipment (UE) to communicate with a base station over a narrow frequency band relative to a second frequency band, in accordance with certain aspects of the present disclosure.

[0062] Fig.11 An example narrowband subframe structure is illustrated in accordance with certain aspects of the present disclosure.

[0063] Fig.12 A comparison between a narrowband subframe structure and a legacy (wideband) subframe structure in accordance with certain aspects of the present disclosure is illustrated.

[0064] Fig.13 Illustrated are example operations that may be performed by a base station to communicate with a UE over a narrow frequency band relative to a second frequency band, in accordance with certain aspects of the present disclosure.

[0065] Fig.14 Illustrated are example operations that may be performed by a user equipment (UE) to communicate with a base station over a narrow frequency band relative to a second frequency band, in accordance with certain aspects of the present disclosure.

[0066] Figures 15A-15C Example subframe sampling sizes for legacy and narrowband subframe structures are illustrated in accordance with certain aspects of the present disclosure.

[0067] Figures 16A-16C Example subframe sampling sizes for a narrowband subframe structure in accordance with certain aspects of the present disclosure are illustrated.

[0068] Fig.17 Illustrated are example operations that may be performed by a base station to communicate with a UE over a narrow frequency band relative to a second frequency band, in accordance with certain aspects of the present disclosure.

[0069] Fig.18 Illustrated are example operations that may be performed by a user equipment (UE) to communicate with a base station over a narrow frequency band relative to a second frequency band, in accordance with certain aspects of the present disclosure.

[0070] Fig.19 Illustrated is an example of determining a narrowband subframe structure used for uplink communications by a first type of UE based on communication characteristics between a base station and a second type of UE in accordance with certain aspects of the present disclosure.

[0071] Fig. 20 Various subframe structures with duration of wideband subframes are illustrated in accordance with certain aspects of the present disclosure.

[0072] Fig.21 Illustrated are example operations that may be performed by a base station to communicate with a UE over a narrow frequency band relative to a second frequency band, in accordance with certain aspects of the present disclosure.

[0073] Fig. 22 Illustrated are example operations that may be performed by a user equipment (UE) to communicate with a base station over a narrow frequency band relative to a second frequency band, in accordance with certain aspects of the present disclosure. Detailed Description

[0074] In some cases, low-cost, low-data-rate UEs may coexist in a network with devices having a larger number of radio resources (e.g., more receive chains). Certain aspects of the present disclosure provide techniques for providing coexistence between low-cost, low-data-rate UEs and UEs having greater communication capabilities by aligning subframe and / or time slot timing for uplink communications by the low-cost, low-data-rate UEs with subframe timing for uplink communications by the UEs having greater communication capabilities.

[0075] The techniques described herein may be used for various wireless communication networks, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and other networks. The terms "network" and "system" are often used interchangeably. A CDMA network may implement radio technologies such as Universal Terrestrial Radio Access (UTRA), cdma2000, and the like. UTRA includes Wideband CDMA (WCDMA), Time Division Synchronous CDMA (TD-SCDMA), and other variants of CDMA. cdma2000 covers IS-2000, IS-95, and IS-856 standards. A TDMA network may implement radio technologies such as Global System for Mobile Communications (GSM). An OFDMA network may implement radio technologies such as Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, The radio technology of etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS). 3GPP Long Term Evolution (LTE) and Advanced LTE (LTE-A) in both frequency division duplex (FDD) and time division duplex (TDD) are new versions of UMTS using E-UTRA, which adopt OFDMA on the downlink and SC-FDMA on the uplink. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). Cdma2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). The technology described herein can be used for the wireless networks and radio technologies mentioned above and other wireless networks and radio technologies. For clarity, certain aspects of these technologies are described below for LTE / Advanced LTE, and LTE / Advanced LTE terms are used in most of the following descriptions. LTE and LTE-A are generally referred to as LTE.

[0076] Figure 1 An example wireless communication network 100 is illustrated in which aspects of the present disclosure may be practiced. For example, the techniques presented herein may be used to assist Figure 1The UE and BS shown in FIG. 4 communicate on a machine-type physical downlink control channel (mPDCCH) using a narrowband (eg, 6 PRBs) based search space.

[0077] The network 100 may be an LTE network or some other wireless network. The wireless network 100 may include several evolved B nodes (eNBs) 110 and other network entities. An eNB is an entity that communicates with a user equipment (UE) and may also be referred to as a base station (BS), a B node, an access point, etc. Each eNB may provide communication coverage for a particular geographic area. In 3GPP, the term "cell" may refer to a coverage area of ​​an eNB and / or an eNB subsystem serving the coverage area, depending on the context in which the term is used.

[0078] An eNB may provide communication coverage for macro cells, pico cells, femto cells, and / or other types of cells. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscriptions. A femto cell may cover a relatively small geographic area (e.g., a residence) and may allow restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG)). An eNB for a macro cell may be referred to as a macro eNB. An eNB for a pico cell may be referred to as a pico eNB. An eNB for a femto cell may be referred to as a femto eNB or a home eNB (HeNB). In Figure 1 In the example shown in , eNB 110a may be a macro eNB for macro cell 102a, eNB 110b may be a pico eNB for pico cell 102b, and eNB 110c may be a femto eNB for femto cell 102c. An eNB may support one or more (e.g., three) cells. The terms "eNB," "base station," and "cell" may be used interchangeably herein.

[0079] The wireless network 100 may also include a relay station. A relay station is an entity that can receive transmissions of data from an upstream station (e.g., an eNB or UE) and send transmissions of the data to a downstream station (e.g., a UE or eNB). A relay station may also be a UE that can relay transmissions for other UEs. Figure 1 In the example shown in FIG. 1 , a relay station 110 d may communicate with macro eNB 110 a and UE 120 d to facilitate communication between eNB 110 a and UE 120 d. A relay station may also be referred to as a relay eNB, a relay base station, a relay, etc.

[0080] The wireless network 100 may be a heterogeneous network including different types of eNBs, such as macro eNBs, pico eNBs, femto eNBs, relay eNBs, etc. These different types of eNBs may have different transmit power levels, different coverage areas, and different effects on interference in the wireless network 100. For example, a macro eNB may have a high transmit power level (e.g., 5 to 40 Watts), while a pico eNB, a femto eNB, and a relay eNB may have a lower transmit power level (e.g., 0.1 to 2 Watts).

[0081] A network controller 130 may be coupled to a set of eNBs and may provide coordination and control for these eNBs. The network controller 130 may communicate with each eNB via a backhaul. The eNBs may also communicate with each other, for example, directly or indirectly via a wireless or wired backhaul.

[0082] UEs 120 (e.g., 120a, 120b, 120c) may be dispersed throughout the wireless network 100, and each UE may be stationary or mobile. UEs may also be referred to as access terminals, terminals, mobile stations, subscriber units, stations, etc. A UE may be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet device, a smart phone, a netbook, a smartbook, an ultrabook, etc. Figure 1 In FIG. 1 , a solid line with double arrows indicates desired transmissions between a UE and a serving eNB, which is an eNB designated to serve the UE on the downlink and / or uplink. A dashed line with double arrows indicates potentially interfering transmissions between a UE and an eNB.

[0083] One or more UEs 120 in the wireless communication network 100 (e.g., an LTE network) may also be narrowband bandwidth UEs. These UEs may coexist with legacy and / or advanced UEs (e.g., capable of operating over a wider bandwidth) in the LTE network and may have one or more capabilities that are limited compared to other UEs in the wireless network. For example, in LTE Release 12, when compared to legacy and / or advanced UEs in the LTE network, narrowband UEs may operate according to one or more of the following: a reduction in maximum bandwidth (relative to legacy UEs), a single receive radio frequency (RF) chain, a reduction in peak rate (e.g., a maximum of 1000 bits for a transport block size (TBS) may be supported), a reduction in transmit power, rank 1 transmission, half-duplex operation, etc. In some cases, if half-duplex operation is supported, the narrowband UE may have a relaxed switching timing from transmit to receive (or from receive to transmit) operation. For example, in one case, a narrowband UE may have a relaxed switching timing of 1 millisecond (ms) compared to a switching timing of 20 microseconds (μs) for legacy and / or advanced UEs.

[0084] In some cases, a narrowband UE (e.g., in LTE Release 12) may also be able to monitor downlink (DL) control channels in the same manner as legacy and / or advanced UEs in an LTE network monitor DL ​​control channels. Release 12 narrowband UEs may still monitor downlink (DL) control channels in the same manner as conventional UEs, for example, monitoring wideband control channels (e.g., physical downlink control channel (PDCCH)) in the first few symbols and narrowband control channels (e.g., enhanced PDCCH (ePDCCH)) that occupy a relatively narrowband but span the length of a subframe.

[0085] According to certain aspects, a narrowband UE may be limited to a specific narrowband assignment of 1.4 MHz or six resource blocks (RBs) that are segmented out from the available system bandwidth while coexisting within a wider system bandwidth (e.g., at 1.4 / 3 / 5 / 10 / 15 / 20 MHz). In addition, a narrowband UE may also be able to support one or more coverage operation modes. For example, a narrowband UE may be able to support up to 15 dB of coverage enhancement.

[0086] As used herein, a device with limited communication resources (e.g., a smaller bandwidth) may be generally referred to as a narrowband UE. Similarly, a legacy device (such as a legacy and / or advanced UE (e.g., in LTE)) may be generally referred to as a broadband UE. Generally speaking, a broadband UE is capable of operating on a larger amount of bandwidth than a narrowband UE.

[0087] In some cases, a UE (e.g., a narrowband UE or a wideband UE) may perform a cell search and acquisition procedure before communicating in the network. Figure 1 As an example, the LTE network illustrated in FIG. 4A , the cell search and acquisition procedure can be performed when the UE is not connected to the LTE cell and wants to access the LTE network. In these situations, the UE may have just powered on, restored the connection after temporarily losing the connection to the LTE cell, and so on.

[0088] In other cases, the cell search and acquisition procedures may be performed while the UE is already connected to an LTE cell. For example, the UE may have detected a new LTE cell and may be preparing for handover to the new cell. As another example, the UE may be operating in one or more low power states (e.g., may support discontinuous reception (DRX)), and upon exiting the one or more low power states, may have to perform cell search and acquisition procedures (even if the UE is still in connected mode).

[0089] Figure 2 It shows that it can be Figure 11. Block diagram of a design of base station / eNB 110 and UE 120 for one of the base stations / eNBs and one of the UEs in the network. Base station 110 may be equipped with T antennas 234a through 234t, and UE 120 may be equipped with R antennas 252a through 252r, where in general T≥1 and R≥1.

[0090] At the base station 110, the transmit processor 220 may receive data for one or more UEs from the data source 212, select one or more modulation and coding schemes (MCS) for each UE based on the CQI received from the UE, process (e.g., encode and modulate) the data for the UE based on the MCS selected for each UE, and provide data symbols to all UEs. The transmit processor 220 may also process system information (e.g., for SRPI, etc.) and control information (e.g., CQI requests, grants, upper layer signaling, etc.), and provide overhead symbols and control symbols. The processor 220 may also generate reference symbols for reference signals (e.g., CRS) and synchronization signals (e.g., PSS and SSS). The transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on ​​data symbols, control symbols, overhead symbols, and / or reference symbols where applicable, and may provide T output symbol streams to T modulators (MOD) 232a to 232t. Each modulator 232 may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator 232 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. T downlink signals from modulators 232a through 232t may be transmitted via T antennas 234a through 234t, respectively.

[0091] At UE 120, antennas 252a to 252r may receive downlink signals from base station 110 and / or other base stations and may provide received signals to demodulators (DEMODs) 254a to 254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) its received signals to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 256 may obtain received symbols from all R demodulators 254a to 254r, perform MIMO detection on the received symbols where applicable, and provide detected symbols. A receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for UE 120 to a data sink 260, and provide decoded control information and system information to a controller / processor 280. A channel processor may determine RSRP, RSSI, RSRQ, CQI, etc.

[0092] On the uplink, at the UE 120, a transmit processor 264 may receive and process data from a data source 262 and control information from a controller / processor 280 (e.g., for reports including RSRP, RSSI, RSRQ, CQI, etc.). The processor 264 may also generate reference symbols for one or more reference signals. The symbols from the transmit processor 264 may be precoded by a TX MIMO processor 266, where applicable, further processed by modulators 254a through 254r (e.g., for SC-FDM, OFDM, etc.), and transmitted to the base station 110. At the base station 110, uplink signals from the UE 120 and other UEs may be received by antennas 234, processed by demodulators 232, detected by MIMO detectors 236, where applicable, and further processed by receive processors 238 to obtain decoded data and control information sent by the UE 120. The processor 238 may provide decoded data to a data sink 239 and decoded control information to the controller / processor 240. The base station 110 may include a communication unit 244 and communicate with the network controller 130 via the communication unit 244. The network controller 130 may include a communication unit 294, a controller / processor 290, and a memory 292.

[0093] Controllers / processors 240 and 280 may direct the operation at base station 110 and UE 120, respectively. For example, processor 280 and / or other processors and modules at UE 120 may execute or direct the following operations: Figure 6 The operation 600 shown in Figure 7 Operation 700 shown in Fig. 9 Operation 900 shown in Fig.10 The operation 1000 shown in Fig.13 The operation 1300 shown in Fig.14 The operation 1400 shown in Fig.17 The operation 1700 shown in Fig.18 The operation 1800 shown in Fig.21 Operation 2100 shown in, and / or Fig. 22 Operations 2200 are shown in FIG. 2. Memories 242 and 282 may store data and program codes for base station 110 and UE 120, respectively. Scheduler 246 may schedule UEs for data transmission on the downlink and / or uplink.

[0094] Figure 3An exemplary frame structure 300 for FDD in LTE is shown. The transmission timeline for each of the downlink and uplink may be divided into units of radio frames. Each radio frame may have a predetermined duration (e.g., 10 milliseconds (ms)) and may be divided into 10 subframes with indices 0 to 9. Each subframe may include two time slots. Each radio frame may thus include 20 time slots with indices 0 to 19. Each time slot may include L symbol periods, e.g., for a normal cyclic prefix (e.g., Figure 3 ) is 7 symbol periods, or 6 symbol periods for an extended cyclic prefix. The 2L symbol periods in each subframe may be assigned indices 0 to 2L-1.

[0095] In LTE, an eNB may transmit a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) on the downlink at the center of the system bandwidth for each cell supported by the eNB. The PSS and SSS may be transmitted in symbol periods 6 and 5, respectively, in subframes 0 and 5 of each radio frame with a normal cyclic prefix, as shown in FIG. Figure 3 . The PSS and SSS may be used by the UE for cell search and acquisition and may contain, among other information, a cell ID and an indication of the duplex mode. The indication of the duplex mode may indicate whether the cell utilizes a time division duplex (TDD) or frequency division duplex (FDD) frame structure. The eNB may transmit a cell-specific reference signal (CRS) across the system bandwidth for each cell supported by the eNB. The CRS may be transmitted in certain symbol periods of each subframe and may be used by the UE to perform channel estimation, channel quality measurement, and / or other functions. The eNB may also transmit a physical broadcast channel (PBCH) in symbol periods 0 to 3 in slot 1 of certain radio frames. The PBCH may carry some system information. The eNB may transmit other system information in certain subframes, such as a system information block (SIB) on a physical downlink shared channel (PDSCH). The eNB may transmit control information / data on a physical downlink control channel (PDCCH) in the first B symbol periods of a subframe, where B may be configurable for each subframe. The eNB may transmit traffic data and / or other data on the PDSCH in the remaining symbol periods of each subframe.

[0096] Channel quality measurements may be performed by the UE according to a defined schedule, such as based on the UE's DRX cycle. For example, the UE may attempt to perform measurements on the serving cell every DRX cycle. The UE may also attempt to perform measurements on non-serving neighbor cells. Measurements on non-serving neighbor cells may be made based on a different schedule than the serving cell, and when the UE is in connected mode, the UE may need to tune away from the serving cell to measure the non-serving cell.

[0097] To facilitate channel quality measurements, the eNB may transmit a cell-specific reference signal (CRS) on specific subframes. For example, the eNB may transmit a CRS on subframes 0 and 5 of a given frame. A narrowband UE may receive the signal and measure the average power of the received signal, or RSRP. A narrowband UE may also calculate a received signal strength indicator (RSSI) based on the total received signal power from all sources. RSRQ may also be calculated based on RSRP and RSSI.

[0098] To facilitate measurements, the eNB may provide measurement configurations to UEs within its coverage area. The measurement configuration may define event triggers for measurement reports, and each event trigger may have associated parameters. When a UE detects a configured measurement event, it may respond by sending a measurement report with information about the associated measurement object to the eNB. The configured measurement event may be, for example, a measured reference signal received power (RSRP) or a measured reference signal received quality (RSRQ) meeting a threshold. A time to trigger (TTT) parameter may be used to define how long a measurement event must last before the UE sends its measurement report. In this way, the UE may signal changes in its radio conditions to the network.

[0099] Figure 4 Two exemplary subframe formats 410 and 420 with normal cyclic prefixes are shown. Available time-frequency resources can be divided into resource blocks. Each resource block can cover 12 subcarriers in a time slot and can include several resource elements. Each resource element can cover one subcarrier in a symbol period and can be used to send a modulation symbol that can be a real value or a complex value.

[0100] Subframe format 410 may be used for two antennas. CRS may be transmitted from antennas 0 and 1 in symbol periods 0, 4, 7, and 11. A reference signal is a signal known a priori to the transmitter and receiver and may also be referred to as a pilot. CRS is a cell-specific reference signal, for example, generated based on a cell identity (ID). Figure 4, for a given resource element with label Ra, a modulation symbol may be transmitted from antenna a on the resource element, and no modulation symbol may be transmitted from other antennas on the resource element. Subframe format 420 may be used with four antennas. CRS may be transmitted from antennas 0 and 1 in symbol periods 0, 4, 7, and 11 and from antennas 2 and 3 in symbol periods 1 and 8. For both subframe formats 410 and 420, CRS may be transmitted on uniformly spaced subcarriers, which may be determined based on a cell ID. CRS may be transmitted on the same or different subcarriers depending on its cell ID. For both subframe formats 410 and 420, resource elements not used for CRS may be used to transmit data (e.g., traffic data, control data, and / or other data).

[0101] The PSS, SSS, CRS and PBCH in LTE are described in the publicly available 3GPP TS 36.211 entitled "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation."

[0102] For FDD in LTE, an interlace structure may be used for each of the downlink and uplink. For example, Q interlaces with indices 0 to Q-1 may be defined, where Q may be equal to 4, 6, 8, 10, or some other value. Each interlace may include subframes spaced apart by Q frames. Specifically, interlace q may include subframes q, q+Q, q+2Q, etc., where q∈{0,...,Q-1}.

[0103] The wireless network may support hybrid automatic repeat request (HARQ) for data transmission on the downlink and uplink. For HARQ, a transmitter (e.g., an eNB) may send one or more transmissions of a packet until the packet is correctly decoded by a receiver (e.g., a UE) or some other termination condition is encountered. For synchronous HARQ, all transmissions of the packet may be sent in each subframe of a single interlace. For asynchronous HARQ, each transmission of the packet may be sent in any subframe.

[0104] A UE may be located within the coverage of multiple eNBs. One of these eNBs may be selected to serve the UE. The serving eNB may be selected based on various criteria such as received signal strength, received signal quality, path loss, etc. Received signal quality may be quantified by signal-to-noise-and-interference ratio (SINR), or reference signal received quality (RSRQ), or some other metric. A UE may operate in a strong interference scenario, where the UE may observe severe interference from one or more interfering eNBs.

[0105] The focus of traditional LTE design is on improving spectrum efficiency, ubiquitous coverage, and enhanced Quality of Service (QoS) support. Current LTE system downlink (DL) and uplink (UL) link budgets are designed for coverage of high-end devices (such as the most advanced smartphones and tablets) that can support relatively large DL and UL link budgets.

[0106] Thus, as described above, one or more UEs in a wireless communication network (e.g., wireless communication network 100) may be devices (such as narrowband UEs) with limited communication resources compared to other (wideband) devices in the wireless communication network. For narrowband UEs, various requirements may be relaxed because only a limited amount of information may need to be exchanged. For example, the maximum bandwidth may be reduced (relative to wideband UEs), a single receive radio frequency (RF) chain may be used, the peak rate may be reduced (e.g., the transport block size may be a maximum of 100 bits), the transmit power may be reduced, rank 1 transmission may be used, and half-duplex operation may be performed.

[0107] In some cases, if half-duplex operation is performed, the narrowband UE may have a relaxed switching time from transmission to reception (or vice versa). For example, the switching time may be relaxed from 20 μs for conventional UEs to 1 ms for narrowband UEs. Release 12 narrowband UEs may still monitor downlink (DL) control channels in the same manner as conventional UEs, for example, monitoring wideband control channels (e.g., PDCCH) in the first few symbols and narrowband control channels (e.g., ePDCCH) that occupy a relatively narrowband but span the length of a subframe.

[0108] In some systems, e.g., in LTE Rel-13, the narrowband may be limited to a specific narrowband assignment within the available system bandwidth (e.g., a narrowband assignment of no more than 6 resource blocks (RBs)). However, the narrowband may be able to re-tune to (e.g., operate and / or camp on) a different narrowband region within the available system bandwidth of the LTE system, e.g., to co-exist within the LTE system.

[0109] As another example of coexistence within an LTE system, a narrowband UE may be able to (repeatedly) receive a legacy physical broadcast channel (PBCH) (e.g., an LTE physical channel that generally carries parameters that may be used for initial access to a cell) and support one or more legacy physical random access channel (PRACH) formats. For example, a narrowband UE may be able to receive a legacy PBCH along with one or more additional repetitions of the PBCH across multiple subframes. As another example, a narrowband UE may be able to transmit one or more repetitions of the PRACH (e.g., with one or more supported PRACH formats) to an eNB in ​​an LTE system. The PRACH may be used to identify the narrowband UE. Additionally, the number of repeated PRACH attempts may be configured by the eNB.

[0110] The narrowband UE may also be a link budget limited device and may operate in different operating modes based on its link budget limitation (e.g., which requires transmitting different amounts of repeated messages to the narrowband UE). For example, in some cases, the narrowband UE may operate in a normal coverage mode where there are almost no repetitions (i.e., the amount of repetitions required for the UE to successfully receive the message may be low or even no repetitions may be required). Alternatively, in some cases, the narrowband UE may operate in a coverage enhancement (CE) mode where there may be a large number of repetitions. For example, for a 328-bit payload, a narrowband UE in CE mode may require 150 or more repetitions of the payload in order to successfully receive the payload.

[0111] In some cases (e.g., for LTE Release 13), a narrowband UE may have limited capabilities with respect to its reception of broadcast and unicast transmissions. For example, the maximum transport block (TB) size of a broadcast transmission received by a narrowband UE may be limited to 1000 bits. In addition, in some cases, a narrowband UE may not be able to receive more than one unicast TB in a subframe. In some cases (e.g., for both the CE mode and the normal mode described above), a narrowband UE may not be able to receive more than one broadcast TB in a subframe. In addition, in some cases, a narrowband UE may not be able to receive both a unicast TB and a broadcast TB in a subframe.

[0112] Narrowband UEs coexisting in an LTE system may also support new messages for certain procedures (such as paging, random access procedures, etc.) (e.g., in contrast to conventional messages used for these procedures in LTE). New messages for paging, random access procedures, etc. may be separated from messages for similar procedures associated with non-narrowband UEs. For example, compared to conventional paging messages used in LTE, narrowband UEs may be able to monitor and / or receive paging messages that non-narrowband UEs may not be able to monitor and / or receive. Similarly, compared to conventional random access response (RAR) messages used in conventional random access procedures, narrowband UEs may be able to receive RAR messages that non-narrowband UEs may not be able to receive. New paging and RAR messages associated with narrowband UEs may also be repeated one or more times (e.g., "bundled"). In addition, different numbers of repetitions (e.g., different bundle sizes) for these new messages may be supported.

[0113] According to certain aspects, narrowband UE and / or narrowband operation can support multiple narrowband areas, wherein each narrowband area spans a bandwidth of no more than 6 RBs in total. In some cases, each narrowband UE in narrowband operation can operate in one narrowband area at a time (e.g., at 1.4MHz or 6 RBs). However, at any given time, the narrowband UE in narrowband operation can also be retuned to other narrowband areas in the wider system bandwidth. In some examples, multiple narrowband UEs can be served by the same narrowband area. In other examples, multiple narrowband UEs can be served by different narrowband areas (e.g., each narrowband area spans 6 RBs). In other examples, different combinations of narrowband UEs can be served by one or more of the same narrowband areas and / or one or more different narrowband areas.

[0114] For example, some systems in LTE Release 13 introduced coverage enhancement and support narrowband UEs as well as other UEs. As used herein, the term coverage enhancement generally refers to any type of mechanism that extends the coverage of a device (such as a narrowband device) within a network. One method for coverage enhancement (CE) is bundling, which refers to transmitting the same data multiple times (e.g., across multiple subframes, or, as will be described in more detail below, across multiple symbols within the same subframe).

[0115] In some systems, a narrowband UE may support narrowband operation while operating within a wider system bandwidth. For example, a narrowband UE may transmit and receive in a narrowband region of the system bandwidth. As mentioned above, the narrowband region may span 6 resource blocks (RBs).

[0116] Some systems may provide up to 15 dB of coverage enhancement to narrowband UEs, which maps to a maximum coupling loss of 155.7 dB between the UE and the eNB. Accordingly, the narrowband UE and the eNB may perform measurements at low SNRs (e.g., -15 dB to -20 dB). In some systems, coverage enhancement may include channel bundling, where messages associated with narrowband UEs may be repeated (e.g., bundled) one or more times.

[0117] Certain devices may be able to communicate using both legacy type communications and non-legacy type communications. For example, some devices may be able to communicate in both narrowband regions (of the overall system bandwidth) as well as wider frequency band regions. Although the above examples cite low-cost or MTC devices communicating via narrowband regions, other (non-low-cost / non-MTC) types of devices may also communicate via narrowband regions, for example using frequency selectivity and directional transmissions.

[0118] Example Uplink Design for Narrowband LTE

[0119] Certain aspects of the present disclosure provide uplink resource allocation for a first type of UE operating on a narrower bandwidth than a second type of UE, such that time slots and / or subframe boundaries of the uplink resources used by the first type of UE are aligned with time slots and / or subframe boundaries of the uplink resources used by the second type of UE.

[0120] In some cases, some UEs (e.g., machine type communication (MTC) UEs) may have a low-cost, low-bandwidth design (e.g., operating on a narrower bandwidth than that used by UEs with higher capability designs), which do not need to be backward compatible with GSM or EDGE technology. However, in some cases, these low-cost, low-power UEs ("narrowband UEs") may be compatible with broadband UEs using the same or similar design to achieve in-band deployment (i.e., the narrowband UE operates within the bandwidth used by the broadband UE) and / or stand-alone deployment (i.e., the narrowband UE operates outside the bandwidth used by the broadband UE).

[0121] For some cases of extreme coverage conditions, a minimum coupling loss (MCL) of 164 dB may be required. A design may be power efficient, support a large number of devices, and be implemented at low cost. In some cases, a 200 kHz channel bandwidth may be used for communications by narrowband UEs.

[0122] Figure 5Various deployments are explained in which narrowband can be deployed within a larger system bandwidth. As explained, the narrowband can be a single LTE resource block with a bandwidth of 180kHz and a 20kHz guard band. By using a single LTE resource block for narrowband communications, the higher layers of the LTE stack and most of the hardware can be reused. Additionally, narrowband UEs can implement enhanced machine type communications (eMTC) and narrowband LTE, which can avoid segmentation. As explained, these narrowbands can overlap at least partially with the system bandwidth (e.g., used by wideband UEs), or can exist outside the system bandwidth.

[0123] In one case, as illustrated by deployment 502, narrowband can be deployed within the system bandwidth (e.g., within the system bandwidth used by broadband UE) and dedicated to narrowband UE. Resource blocks within the broadband channel can be used for narrowband communication. In another case, as illustrated by deployment 504, narrowband can be deployed within a guard band outside (or between) different channels. In another case (although not illustrated), the narrowband channel can be a stand-alone channel. For example, a narrowband channel for communication performed by a narrowband UE can be deployed in a GSM spectrum and a single 200kHz carrier can be used. As illustrated, in some cases, certain subframe subsets 506 can be allocated for narrowband transmission. The subframe subsets 506 used for narrowband transmission can be spread over the system bandwidth. In some cases, as illustrated, the first subframe subset 5061 can partially overlap with other subframe subsets 506 (e.g., the second subframe subset 5062).

[0124] In communications between a UE and an evolved Node B (eNB), the UE typically performs transmissions on a physical random access channel (PRACH). The eNB detects the PRACH transmissions and sends a timing advance command, and the UE transmits information on a physical uplink shared channel (PUSCH), which may have a minimum allocation of 1 resource block (RB).

[0125] In some aspects, a narrowband UE may use 1 RB to perform a PRACH transmission, which may reduce the timing resolution relative to a PRACH transmission sent using a wider bandwidth. The timing resolution of the wider band of 6 RBs may be approximately 1 microsecond, while the timing resolution of the narrowband of 1 RB may be approximately 5 microseconds. Timing advance commands may lose accuracy due to the reduced timing resolution of the 1 RB narrowband and the potential lower signal-to-noise ratio. In some cases, UEs in deep coverage may be power-constrained (i.e., may not benefit from additional bandwidth), which may allow the use of sub-RB assignments to increase the multiplexing capabilities of narrowband communications (e.g., 1 RB bandwidth LTE communications).

[0126] In one design, the uplink digital science of the wideband LTE subframe can be multiplied by a factor of 6 for narrowband LTE communications. Each symbol and cyclic prefix can be six times longer, with a subcarrier spacing of 2.5kHz. Doubling the uplink digital science can allow higher time inaccuracy without losing efficiency in terms of overhead, and can allow a larger number of UEs to be multiplexed simultaneously. However, multiplying the uplink digital science by a factor of 6 can cause the narrowband LTE transmission to lose orthogonality with the wideband (legacy) LTE transmission, which can cause additional interference. If the wideband UE and the narrowband UE are time multiplexed in the same RB, the additional cyclic prefix length may not be able to compensate for the timing advance error. Ultimately, the difference between the scheduling time units of the narrowband UE and the wideband UE may cause problems with scheduling, time domain duplex operation, and multiplexing the narrowband LTE PUSCH with the wideband sounding reference signal.

[0127] In some cases, narrowband LTE transmissions and wideband LTE transmissions may use the same subframe structure and numerology.

[0128] Figure 6 Example operations 600 are illustrated that may be performed, for example, by a base station, to allocate uplink resources to a first type of UE (eg, to a narrowband UE according to “Scheme 1”) in accordance with aspects of the present disclosure.

[0129] Operations 600 may begin at 602, where a base station allocates uplink resources to one or more first type UEs communicating with the base station on a first frequency band, the first frequency band being narrower than a second frequency band used to communicate with second type UEs. The uplink resources may be allocated with the same symbol duration and the same time granularity as uplink resources allocated to the second type UEs, and with a single subcarrier allocated to the first type UEs. At 604, the base station receives an uplink transmission from the first type UE on the allocated resources.

[0130] Figure 7 The following describes the steps according to various aspects of the present disclosure, which may be performed, for example, by a first type UE (eg, a narrowband UE) to allocate resources (eg, by performing the above reference to Figure 6 The example operations 700 of communicating with a base station on a base station assigned with the described operations.

[0131] Operations 700 may begin at 702, where a UE receives an uplink resource allocation for communicating with a base station on a first frequency band narrower than a second frequency band used by a second type of UE to communicate with the base station. The allocated uplink resources may have the same symbol duration and the same time granularity as the uplink resources allocated to the second type of UE, and a single subcarrier may be allocated to the first type of UE. At 704, the UE performs an uplink transmission on the allocated resources.

[0132] In one aspect (hereinafter "Scheme 1"), the uplink digital science for narrowband LTE communications can remain the same as the uplink digital science for broadband (legacy) LTE communications. The subcarriers can have a spacing of 15kHz, and the subframes can have a duration of 1 millisecond. For deep coverage UEs, single frequency modulation transmission can be used. Code division multiplexing (CDM) can be applied in time to multiplex more UEs within the 180kHz available for communication in a resource block (for example, within a single subcarrier or subcarrier group in the 180kHz available for use in a resource block). In some cases, the base station can instruct the UE to rate match around the SRS codeword used by the broadband UE. By using the same digital science for both broadband and narrowband LTE communications, narrowband communications can not interfere with broadband communications, and narrowband LTE communications can be compatible with frequency division duplex (FDD) and time division duplex (TDD) in-band deployment. Because the cyclic prefix length remains the same for both narrowband and broadband LTE communications, timing estimation inaccuracies may occur in narrowband communications.

[0133] Figure 8 An example subframe 800 according to an aspect of the present disclosure is illustrated. As illustrated, the subframe 800 includes 8 time intervals for PUSCH transmission and 6 time intervals for demodulation reference signal (DMRS) transmission. The subframe can be divided into two time slots: a first time slot 810 including PUSCH symbols 0-3 and DMRS symbols A, B, and C; and a second time slot 820 including PUSCH symbols 4-7 and DMRS symbols D, E, and F.

[0134] In one scenario, three UEs may be multiplexed per tone. Code division multiplexing (CDM) with orthogonal sequences between symbols 0, 1, 2, and 3 may be used, where one UE receives 2 sequences and two UEs receive a single sequence. The DMRS for the three UEs may be multiplexed using different spreading sequences, where each UE receives a single DMRS per time slot (e.g., each UE may receive a single DMRS in the first time slot 810 and a single DMRS in the second time slot 820).

[0135] In another scenario, six UEs may be multiplexed per tone. Code division multiplexing (CDM) with 8 orthogonal sequences may be used for symbols 0-7, with two UEs receiving 2 sequences and the remaining four UEs each receiving one sequence. The DMRS for the six UEs may be multiplexed using different spreading sequences, with each UE receiving a single DMRS per subframe.

[0136] In some cases (hereinafter "Scheme 3"), extended cyclic prefix numerology can be used for narrowband LTE transmissions that are performed in-band with wideband LTE transmissions, regardless of whether the wideband LTE transmissions use normal cyclic prefixes or extended cyclic prefixes. Using the extended cyclic prefix, the narrowband transmission can have 6 OFDM symbols per time slot (rather than 7 OFDM symbols in the case of using a normal cyclic prefix). The cyclic prefix can have a length of 16.7 microseconds, which can provide additional buffering for timing errors. Code division multiplexing can be used to increase multiplexing capabilities.

[0137] The increased cyclic prefix length can improve timing accuracy at the expense of efficiency. Narrowband LTE transmissions using the extended cyclic prefix can maintain time alignment with wideband LTE transmissions, regardless of whether the wideband LTE transmission uses a normal cyclic prefix or an extended cyclic prefix. Using an extended cyclic prefix for narrowband LTE transmissions may result in a loss of orthogonality if the wideband LTE transmission uses a normal cyclic prefix.

[0138] In some cases ("Scenario 2" below), increased symbol duration and narrower subcarrier spacing relative to wideband LTE symbol duration and subcarrier spacing may be used for narrowband LTE transmissions.

[0139] Fig. 9 Example operations 900 that may be performed by a base station to allocate uplink resources (per Scheme 2) to a first type of UE (e.g., a narrowband UE) in accordance with various aspects of the present disclosure are illustrated. Operations 900 may begin at 902, where the base station allocates uplink resources to one or more first type of user equipment (UE) communicating with the base station on a first frequency band, the first frequency band being narrower than a second frequency band used to communicate with a second type of UE. The uplink resources may be allocated in a narrowband subframe structure having an increased symbol duration and a narrower subcarrier spacing relative to the uplink resources allocated to the second type of UE. The narrowband subframe structure may include at least two time slots, and each time slot may have the same duration as a subframe structure used to communicate with the second type of UE. At 904, the base station receives an uplink transmission from the first type of UE on the allocated resources.

[0140] Fig.10 The following describes the steps that can be performed by a first type UE to communicate with a base station (eg, to perform the above-mentioned steps with reference to FIG. 1 ) according to various aspects of the present disclosure. Fig. 9 Example operations 1000 of base station) communications are described.

[0141] Operations 1000 may begin at 1002, where a UE receives an uplink resource allocation for communicating with a base station on a first frequency band narrower than a second frequency band used by a second type UE to communicate with the base station. The allocated uplink resources may be allocated in a narrowband subframe structure having an increased symbol duration and a narrower subcarrier spacing relative to the uplink resources allocated to the second type UE. The narrowband subframe structure may include at least two time slots, and each time slot may have the same duration as the subframe structure used to communicate with the second type UE. At 1004, the UE performs an uplink transmission on the allocated resources.

[0142] Fig.11 An example subframe structure 1100 is illustrated in accordance with various aspects of the present disclosure, wherein a narrowband subframe structure has an increased symbol duration and a narrower subcarrier spacing relative to a wideband subframe. As illustrated, the OFDM symbol length is multiplied by a factor of 2 and the subcarrier spacing is divided by a factor of 2 relative to a wideband subframe. For example, each narrowband RB may have 24 subcarriers with a subcarrier spacing of 7.5kHz (compared to a wideband RB with 12 subcarriers and a subcarrier spacing of 15kHz). The cyclic prefix length in the narrowband structure is twice the cyclic prefix length used in the wideband structure. Finally, the length of the subframe is increased to 2 milliseconds in duration, wherein each time slot 1110 and 1120 is 1 millisecond in duration. Alternatively, a narrowband subframe structure may be defined with a duration of 1 millisecond and a reduced number of OFDM symbols relative to a wideband subframe structure. For example, a narrowband subframe structure with a duration of 1 millisecond may have 7 OFDM symbols (e.g., half the number of symbols of a wideband subframe structure).

[0143] Fig.12 A comparison between a wideband (legacy) subframe 1210 and a narrowband slot 1220 in accordance with aspects of the present disclosure is illustrated. As illustrated, a single narrowband slot 1220 has the same duration as a wideband subframe 1210 (i.e., both are 1 millisecond in duration). Alternatively, as described above, a narrowband subframe may be defined with a duration of 1 millisecond.

[0144] The scheduling unit may be 1 resource element during 1 narrowband timeslot. Efficient TDD operation with single timeslot transmission may be enabled. For example, if only one uplink subframe is available, the eNB may grant a single narrowband timeslot to a narrowband UE so that the UE is aligned with a wideband LTE UE.

[0145] By using an extended OFDM symbol length and a narrower subcarrier spacing for narrowband LTE communications relative to broadband LTE communications, the cyclic prefix length can be increased while maintaining the same overhead for narrowband LTE communications and broadband LTE communications. Because 1 narrowband slot has the same duration as 1 broadband subframe, TDD and slot-level scheduling can be used. However, orthogonality may be lost between narrowband LTE communications and broadband LTE communications. Further, multiplying the cyclic prefix length by a factor of 2 may not provide sufficient buffering to account for timing errors.

[0146] In some cases ("Scheme 4" below), narrowband LTE transmissions may use different numerology that is compatible with wideband LTE timing. By using different numerology that is compatible with wideband LTE timing, OFDM symbols (or OFDM symbols with guard bands) may be aligned with slot and / or subframe boundaries. Such alignment may help perform time domain duplex communications with narrowband UEs and wideband UEs.

[0147] Fig.13 Illustrated are example operations 1300 that may be performed by a base station to allocate uplink resources to a first type of UE (eg, a narrowband UE) (according to “Scenario 4”) in accordance with aspects of the present disclosure.

[0148] Operation 1300 may begin at 1302, where a base station allocates uplink resources to one or more first type user equipments (UEs) communicating with the base station on a first frequency band, the first frequency band being narrower than a second frequency band used to communicate with a second type UE. The uplink resources are allocated in a narrowband subframe structure having an increased symbol duration relative to the uplink resources allocated to the second type UE. The narrowband subframe structure may include at least two symbols and have the same duration as a subframe structure used to communicate with the second type UE. At 1304, the base station receives an uplink transmission from the first type UE on the allocated resources.

[0149] Fig.14 The following describes the steps that can be performed by a first type UE to communicate with a base station (eg, perform the steps described above with reference to FIG. 1 ) according to various aspects of the present disclosure. Fig.13 Example operations 1400 of base station) communications described herein.

[0150] Operation 1400 may begin at 1402, where the UE receives an uplink resource allocation for communicating with a base station on a first frequency band narrower than a second frequency band used by a second type UE to communicate with the base station. The uplink resources are allocated in a narrowband subframe structure with an increased symbol duration relative to the uplink resources allocated to the second type UE. The narrowband subframe structure may include at least two symbols and have the same duration as the subframe structure used to communicate with the second type UE. At 1404, the UE performs an uplink transmission on the allocated resources.

[0151] Fig.15A A wideband LTE subframe / slot structure 1510 is illustrated in accordance with some embodiments. With 7 symbols per slot and a sampling frequency of 1.92 MHz, a slot may include 960 time samples and a subframe may include 1920 time samples. Each slot may include a cyclic prefix having a length of 9 or 10 time samples and data having a length of 128 time samples, for a total of 64 time samples used for the cyclic prefix and 896 time samples used for the data.

[0152] In some cases, the subframe numerology (e.g., according to "Scheme 4") can be multiplied by a factor of 7. By multiplying the subframe numerology by 7, one narrowband OFDM symbol can correspond to one wideband time slot in duration. Fig. 15B As illustrated in the narrowband subframe structure 1520 in FIG. 1 , each symbol may have a cyclic prefix of 64 time samples and a data portion of 896 time samples, for a total of 960 time samples per symbol. Thus, each narrowband symbol may be aligned with a wideband time slot.

[0153] In some cases, the subframe numerology may be multiplied by a factor of 6. If the numerology is multiplied by a factor, each wideband LTE slot may have approximately 7 / 6 symbols. Fig.16A As explained in , a large cyclic prefix can be used to align narrowband symbol boundaries to wideband slot boundaries. Narrowband subframe 1610 may include two OFDM symbols, each with a cyclic prefix of 192 time samples and a data portion of 768 time samples (which results in a symbol duration of 960 time samples, or the duration of a single wideband slot). In addition, the numerology can be obtained by extending the legacy LTE extended CP waveform by a factor of 6.

[0154] In another example, a protection period may be introduced. Fig. 15C As illustrated by the narrowband subframe structure 1530 in FIG. 1 , each symbol may have a cyclic prefix lasting 44 time samples and a data portion lasting 896 time samples. In one case, a guard period lasting 40 time samples may be added at the end of the second symbol so that the boundary of the narrowband subframe is aligned with the boundary of the broadband subframe. In another case, a guard period may be added to the end of each narrowband symbol (e.g., a symbol may have a cyclic prefix lasting 44 time samples, a data portion lasting 896 time samples, and a guard period of 20 time samples). The boundary of each narrowband symbol may be aligned with the boundary of a broadband time slot, and the boundary of each narrowband subframe may be aligned with the boundary of a broadband subframe.

[0155] In some cases, a guard period may be added to align narrowband symbols using spreading factor 6 so that narrowband transmissions avoid interfering with wideband SRS transmissions and / or legacy LTE transmissions time multiplexed in the same RB. Fig. 16B The use of symmetric guard periods to provide slot boundary alignment is illustrated. As illustrated, the narrowband subframe 1620 may include two OFDM symbols, and each OFDM symbol may include a cyclic prefix of 106 time samples, a data portion of 768 time samples, and a guard period of 86 time samples. In another scenario, as Fig. 16C As explained in , an asymmetric protection period can be used in a narrowband subframe 1630 to leave the last OFDM symbol in the wideband subframe structure empty for wideband (legacy) SRS transmission. As explained, each symbol can have a cyclic prefix of 96 time samples and a data portion of 768 time samples. After transmitting the second symbol, a protection period of 192 time samples (i.e., 1 / 5 of the wideband slot size) can be used to avoid interference with wideband (legacy) SRS. In some cases, the selection of which uplink numerology to use for narrowband transmission can depend on the characteristics of the wideband deployment.

[0156] Fig.17 Example operations 1700 that may be performed by a base station to allocate resources to a first type of UE (e.g., a narrowband UE) based on communication characteristics over a wideband are illustrated in accordance with various aspects of the present disclosure. Operations 1700 may begin at 1702, where the base station allocates uplink resources to one or more first type of user equipment (UE) communicating with the base station on a first frequency band, the first frequency band being narrower than a second frequency band used to communicate with a second type of UE. The uplink resources are allocated in a narrowband subframe structure having a symbol duration determined at least in part based on communication characteristics between the base station and the second type of UE using the second frequency band. At 1704, the base station receives an uplink transmission from the first type of UE on the allocated resources.

[0157] Fig.18 Example operations 1800 that may be performed by a first type UE to communicate with a base station in accordance with aspects of the present disclosure are illustrated. Operations 1800 may begin at 1802, where the UE receives an uplink resource allocation for communicating with a base station on a first frequency band that is narrower than a second frequency band used by a second type UE to communicate with the base station. The uplink resource allocation is in a narrowband subframe structure having a symbol duration determined at least in part based on communication characteristics between the base station and the second type UE using the second frequency band. At 1804, the UE performs an uplink transmission using the allocated resources.

[0158] Fig.19An example 1900 of the relationship between the communication characteristics between a base station and a second type of UE (e.g., a wideband UE) and the selection of uplink numerology to be used for narrowband communication according to aspects of the present disclosure is illustrated. As illustrated, if the wideband communication uses a normal cyclic prefix and TDD, the narrowband communication can be performed according to Scheme 2, as described above. However, if the wideband communication uses a normal cyclic prefix and FDD, the narrowband communication can be performed according to Scheme 1, as described above. Finally, if the wideband communication uses an extended cyclic prefix, Scheme 3 can be used regardless of whether the wideband communication is performed using TDD or FDD.

[0159] In some cases, the narrowband frame structure can also be selected based on whether SRS appears in certain wideband subframes. For example, if SRS appears, narrowband communication can use scheme 4 with a protection period and an expansion factor of 6. If SRS does not appear, narrowband communication can use scheme 4 with a small protection period and an expansion factor of 7.

[0160] In some cases, the narrowband frame structure may also be selected based on whether the narrowband deployment is in-band, standalone, or in a guard band. For example, if a standalone deployment is used for narrowband communications, numerology that is incompatible with legacy LTE (e.g., having symbols that are not aligned with subframe boundaries) may be used.

[0161] In some cases, such as Fig. 20 As explained in , each of the schemes described above may use a subframe structure with a duration of 1 ms. For Scheme 1 or Scheme 3, when a 1 ms subframe structure is used, the subframe may include 14 symbols (if a normal cyclic prefix is ​​used, as illustrated by subframe 2010) or 12 symbols (if an extended cyclic prefix is ​​used, as illustrated by subframe 2020). For Scheme 3, when the OFDM symbol length is increased and the subcarrier spacing is reduced by a corresponding amount, the 1 ms subframe 2030 may include 7 symbols (i.e., half the number of symbols of a wideband subframe structure using a normal cyclic prefix). Finally, for Scheme 4, the 1 ms subframe 2040 structure may include 2 symbols, and as described above, may optionally include a guard period for rate matching around wideband SRS or wideband (legacy) transmissions time multiplexed in the same RB.

[0162] In some cases, if broadband communication uses TDD, the uplink digital science used by the narrowband UE to communicate with the base station can be based on the number of uplink subframes in the frame. For example, if broadband communication is performed using TDD configuration 0 (with 6 uplink subframes in a frame), the uplink digital science used by the narrowband UE can be multiplied by 6 (as described above); at the same time, if broadband communication is performed using TDD configuration 1 (with 4 uplink subframes in a frame), the uplink digital science used by the narrowband UE can be multiplied by 4. In some cases, the uplink digital science used for narrowband communication can be adjusted based on the availability of uplink subframes in the frame. For example, in TDD configuration 6, the first half frame includes 3 uplink subframes, and the second half frame includes 2 uplink subframes. For the first half frame, the narrowband UE can use uplink digital science multiplied by 6, and for the second half frame, the uplink digital science can be multiplied by 4.

[0163] In some cases, the uplink numerology used to communicate with the eNodeB may be explicitly signaled by the eNodeB to the narrowband UE. The uplink numerology may be broadcast (e.g., in a system information block) or transmitted individually (e.g., in an RRC connection message) to the narrowband UE. In some cases, the uplink numerology may be transmitted in an uplink grant.

[0164] In some cases (scheme "5" below), narrowband LTE transmissions may use uplink numerology that is incompatible with wideband LTE timing.The symbols in the narrowband LTE subframe structure may be aligned with the boundaries of a wideband LTE subframe set.

[0165] Fig.21 Example operations that may be performed by a base station to allocate resources to a first type of UE (eg, a narrowband UE) (according to “Scheme 5”) in accordance with aspects of the present disclosure are illustrated.

[0166] Operations 2100 begin at 2102, where a base station allocates uplink resources to one or more first type user equipment (UE) communicating with the base station on a first frequency band, the first frequency band being narrower than a second frequency band used to communicate with a second type UE. The uplink resources are allocated in a narrowband subframe structure having an increased symbol duration relative to the uplink resources allocated to the second type UE. The symbols in the narrowband subframe structure may be aligned with a boundary of a set of multiple subframe structures used to communicate with the second type UE.

[0167] At 2104, the base station receives an uplink transmission from the first type of UE on the allocated resources.

[0168] Fig. 22 The following describes the steps that can be performed by a first type UE to communicate with a base station (eg, perform the steps described above with reference to FIG. 1 ) according to various aspects of the present disclosure. Fig.21Example operations of base station) communications described herein.

[0169] Operation 2200 may begin at 2202, where the UE receives an uplink resource allocation for communicating with a base station on a first frequency band narrower than a second frequency band used by a second type of UE to communicate with the base station. The uplink resources are allocated in a narrowband subframe structure having an increased symbol duration relative to the uplink resources allocated to the second type of UE. The symbols in the narrowband subframe structure may be aligned with a boundary of a set of multiple subframe structures used to communicate with the second type of UE. At 2204, the UE performs an uplink transmission on the allocated resources.

[0170] In Scheme 5, the OFDM symbol used in the narrowband structure (or the OFDM symbol plus an additional guard period) may be aligned with a subframe boundary or a boundary of a set of multiple subframes used in the wideband structure. In some cases, a guard period or cyclic prefix samples may be added to align the start of the OFDM symbol used in the narrowband structure with a subframe boundary or a boundary of a set of multiple subframes used in the wideband structure.

[0171] For example, the uplink numerology of the narrowband subframe structure may be multiplied by 4, resulting in a 4ms subframe duration, a 2ms slot duration, and a symbol duration that is four times the symbol duration used in the wideband subframe structure. Although the boundaries of the narrowband subframes may not be aligned with the boundaries of the wideband subframes, the OFDM symbols used in the narrowband structure may be aligned with the OFDM symbols used in the wideband structure every other wideband subframe, for example, the OFDM symbols used in the narrowband and wideband structures may be aligned at the start of communication [time 0], at 2ms (after the first slot of 2 wideband subframes and the first narrowband subframe is transmitted), at 4ms (after 4 wideband subframes and one narrowband subframe is transmitted), and so on.

[0172] Those skilled in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or a combination thereof.

[0173] The skilled person will further appreciate that the various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the disclosure herein may be implemented as electronic hardware, software / firmware, or a combination thereof. To clearly illustrate this interchangeability of hardware and software / firmware, various illustrative components, blocks, modules, circuits, and steps are generally described above in terms of their functionality. Whether such functionality is implemented as hardware or software / firmware depends on the specific application and the design constraints imposed on the overall system. The skilled person may implement the described functionality in different ways for each specific application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

[0174] The various illustrative logical blocks, modules, and circuits described in conjunction with the disclosure herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0175] The steps of the method or algorithm described in conjunction with the disclosure herein may be directly embodied in hardware, in a software / firmware module executed by a processor, or in a combination thereof. The software / firmware module may reside in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a phase change memory, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor so that the processor can read and write information from / to the storage medium. Alternatively, a storage medium may be integrated into a processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and the storage medium may reside in a user terminal as discrete components.

[0176] In one or more exemplary designs, the functions described can be implemented in hardware, software / firmware, or a combination thereof. If implemented in software / firmware, each function can be stored on a computer-readable medium or transmitted therefrom as one or more instructions or codes. Computer-readable media include both computer storage media and communication media, including any medium that facilitates the transfer of a computer program from one place to another. Storage media can be any available medium that can be accessed by a general or special-purpose computer. As an example and not limitation, such a computer-readable medium can include RAM, ROM, EEPROM, CD / DVD or other optical disk storage, disk storage or other magnetic storage device, or any other medium that can be used to carry or store the desired program code means in the form of an instruction or data structure and can be accessed by a general or special-purpose computer, or a general or special-purpose processor. Any connection is also properly referred to as a computer-readable medium. For example, if the software / firmware is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc as used herein include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc, where disks tend to reproduce data magnetically and discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0177] As used herein, including in the claims, the term "and / or" used in a list of two or more items means that any of the listed items may be taken alone, or any combination of two or more of the listed items may be taken. For example, if a composition is described as comprising components A, B, and / or C, the composition may comprise only A; only B; only C; a combination of A and B; a combination of A and C; a combination of B and C; or a combination of A, B, and C. Likewise, as used herein, including in the claims, "or" used in a list of items (e.g., in a list of items followed by a phrase such as "at least one of" or "one or more of") indicates a disjunctive list, such that a list such as "at least one of A, B, or C" means A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

[0178] The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the universal principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Therefore, the disclosure is not intended to be limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication by a base station (BS), comprising: allocating uplink resources to one or more first type user equipment (UE) communicating with the BS on a first frequency band narrower than a second frequency band used to communicate with second type UEs, wherein the uplink resources are allocated in a narrowband subframe structure having a symbol duration determined at least in part based on a characteristic of communication between the BS and the second type UEs using the second frequency band, wherein: The characteristics include a time division duplex (TDD) configuration being used for communication between the BS and the second type of UE using the second frequency band, A first symbol duration is selected for a first time slot in the narrowband subframe structure, and wherein a second symbol duration is selected for a second time slot in the narrowband subframe structure, and The first and second symbol durations are selected based on a number of uplink subframes in the TDD configuration; An uplink transmission is received from the first type of UE on the allocated resources. The method of claim 1 , wherein the first frequency band and the second frequency band do not overlap. The method of claim 1 , wherein the first frequency band at least partially overlaps a guard band portion of the second frequency band. 4 . The method of claim 1 , wherein the characteristics include whether time division duplex (TDD) or frequency division duplex (FDD) is used for communication between the BS and the second type UE using the second frequency band.

5. The method of claim 1, wherein the characteristics include whether a normal cyclic prefix (CP) or an extended cyclic prefix is ​​used for communication between the BS and the second type UE using the second frequency band. The method of claim 1 , wherein the characteristic comprises whether the first frequency band is within the second frequency band.

7. The method of claim 1, wherein the characteristic comprises whether a sounding reference signal (SRS) is present in a given subframe.

8. The method of claim 7, wherein the narrowband subframe structure comprises two slots, wherein if SRS is not present in the given subframe, each slot has one symbol.

9. The method of claim 7, wherein: If SRS occurs in the given subframe, the narrowband subframe structure includes at least two symbols in each subframe and includes a guard period to align a boundary of the narrowband subframe structure with a boundary of a subframe structure used to communicate with the second type UE.

10. A method for wireless communication by a first type of user equipment (UE), comprising: receiving an allocation of uplink resources for communicating with a base station (BS) on a first frequency band narrower than a second frequency band used by a second type UE to communicate with the BS, wherein the uplink resources are allocated in a narrowband subframe structure having a symbol duration determined at least in part based on a characteristic of communication between the BS and the second type UE using the second frequency band, wherein: The characteristics include a time division duplex (TDD) configuration being used for communication between the BS and the second type of UE using the second frequency band, A first symbol duration is selected for a first time slot in the narrowband subframe structure, and wherein a second symbol duration is selected for a second time slot in the narrowband subframe structure, and The first and second symbol durations are selected based on a number of uplink subframes in the TDD configuration; Uplink transmission is performed using the allocated resources. The method of claim 10 , wherein the first frequency band and the second frequency band do not overlap.

12. The method of claim 10, wherein the first frequency band at least partially overlaps a guard band portion of the second frequency band.

13. The method of claim 10, wherein the characteristics include whether time division duplex (TDD) or frequency division duplex (FDD) is used for communication between the BS and the second type UE using the second frequency band.

14. The method of claim 10, wherein the characteristics include whether a normal cyclic prefix (CP) or an extended cyclic prefix is ​​used for communication between the BS and the second type UE using the second frequency band.

15. The method of claim 10, wherein the characteristic comprises whether the first frequency band is within the second frequency band.

16. The method of claim 10, wherein the characteristic comprises whether a sounding reference signal (SRS) is present in a given subframe.

17. The method of claim 16, wherein the narrowband subframe structure comprises two slots, with one symbol in each slot if SRS is not present in the given subframe.

18. The method of claim 16, wherein: If SRS occurs in the given subframe, the narrowband subframe structure includes at least two symbols in each subframe and includes a guard period to align a boundary of the narrowband subframe structure with a boundary of the subframe structure used by the second type UE to communicate with the BS.

19. An apparatus for wireless communication by a base station (BS), comprising: at least one processor configured to execute the method according to any one of claims 1 to 9; as well as A memory coupled to the at least one processor.

20. An apparatus for wireless communication by a user equipment (UE), comprising: at least one processor configured to execute the method of any one of claims 10 to 18; as well as A memory coupled to the at least one processor.

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