Intra-RRC high-bandwidth grant request techniques

This disclosure relates to techniques for UEs (including link budget limited UEs) to improve communications performance with a cellular network. A UE may be configured to provide a request (for a first process executed by the UE) for a high-bandwidth connection to a base station of a cellular network during a first RRC connection. In some embodiments, the RRC connection is established by another process. In some embodiments, the UE is configured to receive signaling from the base station indicating that the base station cannot satisfy the high-bandwidth connection request and the UE is configured not to send or receive data for the high-bandwidth connection during the first RRC connection in response to the signaling. In some embodiments, the UE is configured to re-send the request on a second, subsequent RRC connection that is not established by the first process. In some embodiments, the UE is configured to opportunistically re-send the request on subsequent RRC connections established by one or more other processes until the base station is able to grant the request.

FIELD

The present application relates to wireless devices, and more particularly to an apparatus, system, and method for providing improved communication procedures for link budget limited wireless devices.

DESCRIPTION OF THE RELATED ART

Wireless communication systems are rapidly growing in usage. Additionally, there exist numerous different wireless communication technologies and standards. Some examples of wireless communication technologies include GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE Advanced (LTE-A), HSPA, 3GPP2 CDMA2000 (e.g., 1×RTT, 1×EV-DO, HRPD, eHRPD), IEEE 802.11 (WLAN or Wi-Fi), IEEE 802.16 (WiMAX), Bluetooth, and others.

Wireless communication can be useful for a wide breadth of device classes, ranging from relatively simple (e.g., potentially inexpensive) devices, which may have limited capabilities, to relatively complex (e.g., potentially more expensive) devices, which may have greater capabilities. Such devices may have different characteristics with respect to processing, memory, battery, antenna (power/range, directionality), and/or other capabilities. Devices that exhibit relatively limited reception and/or transmission capabilities (due to one or more of device design, antenna design or size, device size, battery size, current transmission medium conditions, and/or other factors) may be referred to in some instances as link budget limited devices.

In some situations high-bandwidth application traffic can consume significant power of a mobile device, especially when network traffic is high or when radio frequency (RF) conditions are poor. Some of this application traffic may be non-critical, such as uploading photos or downloading applications or application updates. Techniques for reducing power consumption for these transmissions may be desired.

SUMMARY

Embodiments are presented herein of methods for providing improved communication performance for wireless devices, and of devices (e.g., wireless devices (UEs), base stations) configured to implement the methods. For example, embodiments presented herein may provide improved LTE or LTE-Advanced performance for wireless devices, such as link budget limited devices. Some embodiments may relate to a user equipment (UE) mobile device configured to perform a subset or all of the operations described herein. The UE device may comprises more or more processing elements, one or more antennas, and one or more radios.

In some embodiments, the UE is configured to provide a request (for a first process executed by the UE) for a high-bandwidth connection to a base station of a cellular network during a first RRC connection. In some embodiments, the RRC connection is established by a second process executed by the UE, rather than the first, requesting process. In some embodiments, the UE is configured to receive, during the first RRC connection, signaling from the base station indicating that the base station does not have sufficient number of grants for the UE to satisfy the high-bandwidth connection request. In some embodiments, the UE is configured not to send or receive data for the high-bandwidth connection during the first RRC connection in response to the signaling from the base station. In some embodiments, the UE is configured to re-send the request on a second, subsequent RRC connection that is not established by the first process. In some embodiments, the UE is configured to opportunistically re-send the requests on subsequent RRC connections established by one or more other processes until the base station is able to grant the request. This may allow the base station to eventually grant the request during a trough in network traffic without overburdening RRC signaling, because existing RRC connections are used. The UE may be configured to submit a simple request and the base station quickly respond with a simple grant or denial for the high-bandwidth connection, allowing the UE to perform any other desired communication and then enter a sleep or idle mode until the next request. This disclosed techniques may reduce power consumption by sending and/or receiving data for high-bandwidth requests during shorter time intervals when the base station can provide high bandwidth while the UE can enter a sleep or idle mode at other times.

The techniques described herein may be implemented in and/or used with a number of different types of devices, including but not limited to cellular phones, tablet computers, wearable computing devices, portable media players, and any of various other computing devices.

DETAILED DESCRIPTION

Acronyms

The following acronyms are used in the present disclosure.

3GPP: Third Generation Partnership Project

3GPP2: Third Generation Partnership Project 2

UMTS: Universal Mobile Telecommunication System

EUTRA: Evolved UMTS Terrestrial Radio Access

GSM: Global System for Mobile Communications

LTE: Long Term Evolution

PLMN: Public Land Mobile Network

CQI: Channel Quality Indicator

QCI: Quality of Service Class Identifier

GBR: Guaranteed Bit Rate

RAT: Radio Access Technology

RRC: Radio Resource Control

RSRP: Reference Signal Received Power

RSRQ: Reference Signal Received Quality

RLC: Radio Link Control

RLF: Radio Link Failure

UE: User Equipment

UMTS: Universal Mobile Telecommunications System

Terms

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

Link Budget Limited—includes the full breadth of its ordinary meaning, and at least includes a characteristic of a wireless device (a UE) which exhibits limited communication capabilities, or limited power, relative to a device that is not link budget limited, or relative to devices for which a radio access technology (RAT) standard has been developed. A UE that is link budget limited may experience relatively limited reception and/or transmission capabilities, which may be due to one or more factors such as device design, device size, battery size, antenna size or design, transmit power, receive power, current transmission medium conditions, and/or other factors. Such devices may be referred to herein as “link budget limited” (or “link budget constrained”) devices. A device may be inherently link budget limited due to its size, battery power, and/or transmit/receive power. For example, a smart watch that is communicating over LTE or LTE-A with a base station may be inherently link budget limited due to its reduced transmit/receive power and/or reduced antenna. Alternatively, a device may not be inherently link budget limited, e.g., may have sufficient size, battery power, and/or transmit/receive power for normal communications over LTE or LTE-A, but may be temporarily link budget limited due to current communication conditions, e.g., a smart phone being at the edge of a cell, etc. It is noted that the term “link budget limited” includes or encompasses power limitations, and thus a power limited device may be considered a link budget limited device.

FIG. 1illustrates an exemplary (and simplified) wireless communication system, according to some embodiments. It is noted that the system ofFIG. 1is merely one example of a possible system, and embodiments may be implemented in any of various systems, as desired.

The base station102A may be a base transceiver station (BTS) or cell site, and may include hardware that enables wireless communication with the UEs106A through106N. The base station102A may also be equipped to communicate with a network100(e.g., a core network of a cellular service provider, a telecommunication network such as a public switched telephone network (PSTN), and/or the Internet, among various possibilities). Thus, the base station102A may facilitate communication between the user devices (UEs) and/or between the UEs and the network100.

The communication area (or coverage area) of the base station may be referred to as a “cell.” The base station102A and the UEs106may be configured to communicate over the transmission medium using any of various radio access technologies (RATs), also referred to as wireless communication technologies, or telecommunication standards, such as GSM, UMTS (WCDMA, TD-SCDMA), LTE, LTE-Advanced (LTE-A), HSPA, 3GPP2 CDMA2000 (e.g., 1×RTT, 1×EV-DO, HRPD, eHRPD), Wi-Fi, WiMAX etc.

FIG. 2illustrates user equipment106(e.g., one of the devices106A through106N) in communication with a base station102(e.g., one of the base stations102A through102N), according to some embodiments. The UE106may be a device with cellular communication capability such as a mobile phone, a hand-held device, a wearable device, a computer or a tablet, or virtually any type of wireless device.

The UE106may include a processor that is configured to execute program instructions stored in memory. The UE106may perform any of the method embodiments described herein by executing such stored instructions. Alternatively, or in addition, the UE106may include one or more programmable hardware elements such as an FPGA (field-programmable gate array) that is configured to perform any of the method embodiments described herein, or any portion of any of the method embodiments described herein.

FIG. 3—Exemplary Block Diagram of a UE

As shown, the SOC300may be coupled to various other circuits of the UE106. For example, the UE106may include various types of memory (e.g., including NAND flash310), a connector interface320(e.g., for coupling to a computer system, dock, charging station, etc.), the display360, and wireless communication circuitry330(e.g., for LTE, Wi-Fi, GPS, etc.).

The UE device106may include at least one antenna (and possibly multiple antennas, e.g., for MIMO and/or for implementing different wireless communication technologies, among various possibilities), for performing wireless communication with base stations and/or other devices. For example, the UE device106may use antenna(s)335to perform the wireless communication. As noted above, the UE106may be configured to communicate wirelessly using multiple wireless communication technologies in some embodiments.

As described further subsequently herein, the UE106may include hardware and software components for implementing features and methods described herein. The processor302of the UE device106may be configured to implement part or all of the methods described herein, e.g., by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). In other embodiments, processor302may be configured as a programmable hardware element, such as an FPGA (Field Programmable Gate Array), or as an ASIC (Application Specific Integrated Circuit). Alternatively (or in addition), the processor302of the UE device106, in conjunction with one or more of the other components300,304,306,310,320,330,335,340,350,360may be configured to implement part or all of the features described herein.

FIG. 4—Exemplary Block Diagram of a Base Station

The base station102may be configured to communicate wirelessly using multiple wireless communication standards. In some instances, the base station102may include multiple radios, which may enable the base station102to communicate according to multiple wireless communication technologies. For example, as one possibility, the base station102may include an LTE radio for performing communication according to LTE as well as a Wi-Fi radio for performing communication according to Wi-Fi. In such a case, the base station102may be capable of operating as both an LTE base station and a Wi-Fi access point. As another possibility, the base station102may include a multi-mode radio which is capable of performing communications according to any of multiple wireless communication technologies (e.g., LTE and Wi-Fi).

Exemplary Improved Handling of High-Bandwidth Traffic

A UE may communicate various types of application traffic with a base station, including some traffic that is more critical (e.g., has more real-time requirements) and some traffic that is less critical, or even non-critical (e.g., has less or no real-time requirements). Some types of application traffic require high bandwidth but are non-critical to users in terms of real-time performance. Examples of such non-critical high-bandwidth traffic include photo uploads to a cloud server and application software downloads, such as from an app store. This high-bandwidth application traffic can consume large amounts of power in highly loaded and/or poor RF condition environments.

Because this application traffic is non-critical, however, the communication activity for these applications can be scheduled in RRC connections during eNB trough periods, i.e., periods when the base station is less busy (and hence when an eNB is able to provide better grants and better data throughput). These base station trough periods may occur a number of times during a day. Therefore, for at least some embodiments described herein, the base station and/or the UE may operate to schedule non-critical application traffic (and especially high-bandwidth, non-critical traffic) during such base station trough periods.

In some embodiments, a base station is configured to immediately respond to non-critical high-bandwidth requests that it cannot grant in the near future. In response, the UE may perform tasks not requiring high-bandwidth throughputs and/or time-critical tasks, then re-send the request for a non-critical high-bandwidth connection on a subsequent RRC connection. In various embodiments, a process with non-critical high-bandwidth requests is configured to opportunistically transmit the requests using RRC connections established by other processes, which may reduce RRC signaling and thus reduce network congestion and power consumption.

Embodiments described here may be particularly useful in the case of a link-budget limited device, which may have reduced capabilities as compared to other mobile communication devices conforming to the RAT standard, including, for example, an antenna deficiency. It is noted that the various operations described herein for link budget limited devices also applies to power limited UE devices, where the term “link budget limited” includes or encompasses power limited devices. Further, various techniques described herein may be implemented using devices that are not link budget limited.

FIG. 5is a flowchart diagram illustrating a method to perform improved scheduling of non-critical, high-bandwidth traffic between a UE and a base station, according to some embodiments. While elements of the method ofFIG. 5are described substantially with reference to the LTE wireless communication technology, part or all of the method may be used in conjunction with other wireless communication technologies, as desired.

The method shown inFIG. 5may be used in conjunction with any of the computer systems or devices shown in the aboveFIGS. 1-4, among other devices. In various embodiments, some of the elements of the scheme shown may be performed concurrently, in a different order than shown, or may be omitted. Additional elements may also be performed as desired. As shown, the scheme may operate as follows.

In502a first UE process begins connection establishment with a base station (eNB). This may involve arranging an RRC connection with the base station. The first UE process may generate time-critical traffic.

In504, during or soon after the connection establishment, a second, different UE process (which may or may not belong to a different application than the first process) opportunistically requests a high-bandwidth connection via the connection established by the first UE process (i.e., using an existing RRC connection). The second UE process may wake to make the request in response to detecting the RRC connection by the first process. The request may be for non-time-critical traffic such as photo uploads, application downloads/updates, etc.

In some embodiments, the second UE process may also or alternatively make requests for high-bandwidth connections via one or more RRC connections established by the second process itself rather than another process. Thus, various actions described herein as performed using connections established by other processes may be performed using connections established by the requesting process. Piggybacking on other processes' connection(s), however, may reduce signaling overhead in some embodiments. The high-bandwidth request by the UE may be signaled in any of various manners, such as using an extended MAC (media access controller) CE (control element), using an RRC Connection Request (RRCConnectionRequest), or using other signaling techniques to make a simple request.

In506, after the high-bandwidth connection request is provided from the UE to the base station, the UE may enter a sleep mode. For example, the UE may enter a long connected discontinuous reception (C-DRX) cycle. In other embodiments, the UE may not enter a sleep cycle, but may perform other transmissions, etc. while waiting for a response to the request, e.g., depending on current tasks being executed by the UE.

In508the base station determines whether it can provide a sufficient amount of grants (which may include UL and/or DL grants) in the near term to satisfy the high-bandwidth connection request (e.g., in upcoming scheduled on-duration cycles). In other words, the base station determines if it can allocate a sufficient amount of near-term bandwidth (in the form of UL and/or DL grants) to the UE to enable the UE to perform the high-bandwidth transfer. In either case, the base station responds to the request as soon as it has made the determination, in some embodiments. In some embodiments the response indicates the requesting application so that the UE can handle the response appropriately.

If the base station can provide a sufficient number of near-term grants to satisfy the high-bandwidth connection request as determined in508, then operation proceeds to512. In512the base station signals to the UE that it has sufficient near-term grants. In514, the UE then wakes from the long sleep cycle (if sleeping) and accepts the grants. In516, the UE performs the communications task (e.g., transmitting and/or receiving data) using the granted high-bandwidth connection.

If the base station cannot provide a sufficient number of near term grants to satisfy the high-bandwidth connection request as determined in508, then operation proceeds to522. In522, the base station signals to the UE that it does not have sufficient near term grants. In524, the UE performs low bandwidth tasks (e.g., as specified by the first UE process and/or the second UE process) but does not transmit or receive data for the requested high-bandwidth connection. The UE may subsequently enter a long sleep cycle after performing the low bandwidth tasks.

In526, the UE opportunistically attempts to obtain the high-bandwidth connection using RRC connections established by one or more other processes (which may include RRC connections of the first UE process). This intra-RRC connection technique may allow the UE to utilize sleep cycles until a network trough occurs, without the base station needing to store complex UE state or schedule the high-bandwidth communications a significant time interval ahead. Rather, in these embodiments, the UE may be said to poll the base station (e.g., using existing RRC connections) until operational conditions are acceptable and the base station grants the request.

FIGS. 6-9illustrate exemplary connection scenarios based on whether the requesting application/process is persistent and whether the network is able to initially grant the high-bandwidth request.

InFIG. 6, application A1is not persistent and the network is able to provide the requested connection. As shown, an RRC connection request is sent (by another process or by application A1) and a socket is opened for A1. In the illustrated embodiment, A1sends an app-aware request that identifies A1and requests non-time-critical high-bandwidth transmissions via the RRC connection. In this scenario, application A1is not persistent and a socket is opened for the request. In typical scenarios, however, application A1may piggyback on an existing persistent connection and/or other non-persistent connections to request high-bandwidth connections. As shown, the socket for A1is established and the UE begins a long connected sleep (e.g., using C-DRX). In the illustrated embodiment, a faster out-of-sync (OOS) indication is used (e.g., less than 200 milliseconds) by the UE during this period. At this point, the UEs UL resources (e.g., SR, PUCCH, and/or PUSCH resources) may be released and the network may distribute these resources to other UEs. In other embodiments, an extended media access control (MAC) control element (CE) or a physical layer indication may be used to request the high-bandwidth connection.

In this scenario, in response to the UE's request for non-time-critical high-bandwidth transmissions, the network is able to provide the requested grants at the full buffer guaranteed allocation point. The high-bandwidth communication is complete at the full buffer guaranteed complete point, after which the UE may again enter a long connected sleep mode. Depending on current operating conditions, the UE may enter an RRC idle mode at this point rather than a long connected sleep. In the illustrated embodiment, the socket for the A1application is then closed and the RRC connection is released. In some embodiments, the UE either requests fast dormancy or waits for RRC inactivity using a long C-DRX cycle.

InFIG. 7, application A1is persistent and the network is able to provide the requested connection. Scenario2is similar to scenario1shown inFIG. 6, except that the socket is not established or torn down because A1is persistent (i.e., the A1socket is always established during the relevant interval). Persistent applications/processes (such as those associated with push notifications, for example) may send a packet periodically to maintain a socket, which may save TCP round-trip time, for example. For non-persistent applications/processes, a socket may be set up and torn down when a connection is needed (e.g., to backup a photo, etc.).

InFIG. 8, application A1is not persistent and the application is initially unable to provide the requested high-bandwidth connection. In contrast to scenario1, in scenario3the network determines that it cannot provide sufficient grants in upcoming on-duration cycles and gives an app-aware negative response that identifies the requesting application/process and indicates the negative nature of the response. (The negative response may be an app-aware response given at the RRC layer, MAC layer, physical layer, using NAS signaling, etc.) Based on the negative response, the UE enters another long connected sleep cycle. The UE may continue to initiate requests using existing RRC connections and receive responses until the network is able to provide the desired high-bandwidth connection, e.g., during a low-traffic interval. Although not shown, multiple RRC connections for other processes may exist during the illustrated long connected sleep cycles and A1may utilize those RRC connections to re-submit the requests (resubmissions not shown) until the network can grant the request. This may reduce RRC signaling and thus reduce power consumption, in some embodiments. Further, because the network may respond quickly to each request, the on-duration between long connected sleep cycles may be small. The UE and/or base station may maintain threshold information used to determine whether the base station can grant enough resources to satisfy the high-bandwidth connection request.

Eventually, (after three cycles in the illustrated embodiment, although the number of cycles is exemplary and may vary) the network provides a positive response and the UE uses the allocation to transmit and/or receive data using the provided high-bandwidth connection. Subsequently, the A1socket and the RRC connection are closed. In some embodiments, the UE either requests fast dormancy at this point or waits for RRC inactivity using a long C-DRX cycle.

In some embodiments, scenarios1and2may not occur or may almost never occur, as one or more persistent processes will almost always be initiating RRC connections, which application A1can utilize to send its app-aware request(s).

InFIG. 9, application A1is persistent and the network is not initially able to provide the requested connection. Scenario4is similar to scenario3, except that A1is persistent, so the application A1socket is not established or torn down.

FIG. 10is a flow diagram illustrating a method for requesting a high-bandwidth connection over an RRC connection, according to some embodiments. The method shown inFIG. 10may be used in conjunction with any of the computer circuitry, systems, devices, elements, or components disclosed herein, among others. In various embodiments, some of the method elements shown may be performed concurrently, in a different order than shown, or may be omitted. Additional method elements may also be performed as desired.

At1010, in the illustrated embodiment, UE106provides a request for a high-bandwidth connection for a first process. The request is provided to a base station using a first RRC connection. In some embodiments, the first RRC connection is established by a second, different process running on UE106. In these embodiments, the first process may opportunistically use the first RRC connection to make the request, e.g., based on determining that the first RRC connection is available to make the request.

At1020, in the illustrated embodiment, UE106receives, during the first RRC connection, first signaling from the base station indicating that the base station does not have a sufficient number of grants for the apparatus to satisfy the high-bandwidth connection request. This may be based on congestion from other mobile devices, for example.

At1030, in the illustrated embodiment, UE106does not transmit or receive data for the high-bandwidth connection during the first RRC connection in response to receiving the first signaling. In some embodiments, UE106instead waits until a subsequent RRC connection is established (e.g., by another process or the requesting process) to request the high-bandwidth connection. In some embodiments, UE106then receives, during the subsequent RRC connection, second signaling indicating that the base station has a sufficient number of uplink grants to satisfy the request. In some embodiments, UE106is configured to transmit and/or receive data using the high-bandwidth connection during the second RRC connection in response to receiving the second signaling.

In some embodiments, UE106enters a C-DRX mode after providing the request and the first signaling indicates that the base station does not have a sufficient number of uplink grants in upcoming on-duration periods of the C-DRX mode to satisfy the high-bandwidth connection request.

In various embodiments, the application/process requesting high-bandwidth connections may be a background application/process. In other embodiments, similar techniques may be used for foreground traffic, e.g., for HTTP live streaming (HLS). In these embodiments, higher bursts of data may be downloaded during on-duration cycles of the foreground application/process based on the disclosed grant requests and negative/positive responses. For example, physical layer conditions may vary and the application may request a particular quality in the next grant. This may conserve baseband power by using high-bandwidth connections during network trough intervals and sleeping at other times, which may result in a greater amount of overall sleep time, etc. As used herein “high-bandwidth” may be defined according to various criteria and/or threshold values, e.g., based on physical layer conditions. Therefore a “high-bandwidth”request for one UE or application may or may not be considered high-bandwidth for another UE and/or application.