Patent Application
20140274011
I. Field
The present disclosure relates generally to communication, and more specifically to techniques for controlling the operation of a user equipment (UE).
II. Background
Wireless communication networks are widely deployed to provide various communication content such as voice, video, packet data, messaging, broadcast, etc. These wireless networks may be multiple-access networks capable of supporting multiple users by sharing the available network resources. Examples of such multiple-access networks include Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, and Single-Carrier FDMA (SC-FDMA) networks.
A wireless network may include a number of base stations that can support communication for a number of UEs. A UE may communicate with a base station via the downlink and uplink. The downlink (or forward link) refers to the communication link from the base station to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the base station.
A wireless network may support flexible operation. For example, the wireless network may operate based on a system bandwidth selected from a set of possible system bandwidths. The configuration of the wireless network may impact communication between UEs and the wireless network.
A PHY parameter is a parameter that affects operation of a physical layer at a UE and a wireless network, and both would need to be aware of the PHY parameter. Some exemplary PHY parameters include a system bandwidth, an uplink-downlink configuration, a number of antennas, a number of carriers, etc.
In one design, a UE may receive system information from a wireless network. The UE may obtain at least one PHY parameter of the wireless network, at a physical layer on the UE, based on the system information and/or other signaling. The UE may provide the at least one physical layer parameter to at least one entity within the UE for use to control internal operation of the UE. Internal operation of the UE refers to operation of the UE that is transparent to the wireless network, e.g., operation that does not need to be reported to the wireless network.
In another design, the UE may provide the at least one physical layer parameter to a memory and flow controller for use to control at least one data buffer within the UE and/or to control at least one data flow within the UE. The UE may provide the at least one physical layer parameter to a clock controller for use to adjust clock rates for transmit tasks, receive tasks, and/or other tasks at the UE. The UE may provide the at least one physical layer parameter to a thermal mitigator for use for thermal mitigation at the UE. The UE may provide the at least one physical layer parameter to an application controller for use to control operation of at least one application running on the UE. The UE may also provide the at least one physical layer parameter to other entities for use to control other operations of the UE.
Various aspects and features of the disclosure are described in further detail below.
The techniques described herein may be used for various wireless communication networks and radio access technologies. The terms “network” and “system” are often used interchangeably. For example, the techniques may be used for CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and other wireless networks. Different wireless networks may implement different radio access technologies. For example, a CDMA network may implement a radio access technology such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband CDMA (WCDMA), Time Division Synchronous CDMA (TD-SCDMA), and other variants of CDMA. cdma2000 includes IS-2000, IS-95 and IS-856 standards. A TDMA network may implement a radio access technology such as Global System for Mobile Communications (GSM). An OFDMA network may implement a radio access technology such as Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM®, etc. UTRA, E-UTRA and GSM are part of Universal Mobile Telecommunication System (UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are recent releases of UMTS that use E-UTRA. UTRA, E-UTRA, GSM, UMTS, LTE and LTE-A 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 techniques described herein may be used for the wireless networks and radio access technologies mentioned above as well as other wireless networks and radio access technologies. For clarity in description, certain aspects of the techniques are described below for LTE, and LTE terminology is used in much of the description below. It should be noted that other terminologies apply to other techniques and technologies.
A serving gateway 130 may perform various functions to support data communication for UEs 120. For example, serving gateway 130 may perform functions related to Internet Protocol (IP) data transfer for UEs 120 such as data routing and forwarding, mobility anchoring, etc. Serving gateway 130 may also perform various functions such as support for handover between eNBs 110, buffering, routing and forwarding of data for UEs 120, initiation of network-triggered service request procedures, accounting functions for charging, etc.
UEs 120 may be dispersed throughout the wireless network, and each UE 120 may be stationary or mobile. A UE 120 may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, etc. A UE 120 may be a cellular phone, a smartphone, a tablet, a wireless communication device, a personal digital assistant (PDA), a wireless modem, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a netbook, a smartbook, etc.
A UE 120 may communicate with an eNB 110 and other network entities via various protocols designed to facilitate data transmission. Each protocol may perform a set of functions and may interface with one or more other protocols.
The link layer may be dependent on network/radio access technology. For the user plane in LTE, the link layer for the UE includes three sublayers for Packet Data Convergence Protocol (PDCP), Radio Link Control (RLC), and Medium Access Control (MAC), which are terminated at the eNB. The UE further communicates with the eNB via E-UTRA air-link interface at the physical layer. The eNB may communicate with the serving gateway via IP and a technology-dependent interface for the link layer and the physical layer. In LTE, the link layer between the eNB and the serving gateway includes GPRS Tunneling Protocol for User Plane (GTP-U), User Datagram Protocol (UDP), IP, L2 and L1.
Wireless network 100 may utilize FDD and/or TDD. For FDD, the downlink and uplink are allocated separate frequencies, and downlink transmissions and uplink transmissions may be sent concurrently on the separate frequencies. For TDD, the downlink and uplink share the same frequency, and downlink and uplink transmissions may be sent on the same frequency in different time intervals.
Table 1 lists seven uplink-downlink configurations supported by LTE for TDD. Each uplink-downlink configuration indicates whether each subframe is a downlink subframe (denoted as “D” in Table 1), or an uplink subframe (denoted as “U” in Table 1), or a special subframe (denoted as “S” in Table 1). Uplink-downlink configuration 1 is symmetric and includes an equal number of downlink subframes and uplink subframes. Uplink-downlink configurations 2, 3, 4 and 5 are downlink heavy and include more downlink subframes than uplink subframes. Uplink-downlink configurations 0 and 6 are uplink heavy and include more uplink subframes than downlink subframes. An uplink-downlink configuration selected for use has an impact on throughput on the downlink as well as throughput on the uplink.
As shown in
A cell may transmit downlink control information (DCI) on a Physical Downlink Control Channel (PDCCH) in the control region to one or more UEs. The DCI may include a downlink grant, an uplink grant, power control information, etc. The cell may transmit data and/or other information on a Physical Downlink Shared Channel (PDSCH) in the data region to one or more UEs. The cell may transmit a Physical Broadcast Channel (PBCH) in symbol periods 0 to 3 in slot 1 of subframe 0 in certain radio frames, as shown in
A cell may transmit system information to convey various parameters used to support communication with UEs. In LTE, the system information may be partitioned into a master information block (MIB) and a number of system information blocks (SIBs) to enable efficient transmission and reception of the system information. The MIB may include a limited number of essential parameters used to acquire other information from the cell. The MIB may be transmitted periodically on the PBCH with a fixed schedule of 40 ms in subframe 0 of each radio frame for which (SFN mod 4)=0, where “mod” denotes a modulo operation.
Multiple (K) SIBs may be defined and may be referred to as system information block types 1 through K, or SIB1 through SIB K. In general, K may be any integer value, e.g., K=13 for LTE Release 10. Each SIB may carry a specific set of parameters to support operation by UEs. SIB1 may carry (i) scheduling information for N SI messages and (ii) a mapping of SIBs to SI messages, where N may be one or greater. The scheduling information may include the periodicity of each SI message and the time duration in which each SI message might be sent. The mapping may indicate which SIBs are sent in each SI message, with each SIB being sent in only one SI message. SIB1 and SI messages may be transmitted on the PDSCH. SIB1 may be transmitted at a periodicity of 80 ms in subframe 5 of each radio frame for which (SFN mod 8)=0. SIB1 may be partitioned into four parts and transmitted in subframe 5 of four even-numbered radio frames. SIB1 may thus be transmitted every 20 ms and may repeat every 80 ms.
A cell in a wireless network may broadcast various configurable physical layer (PHY) parameters that define the configuration of the cell. A PHY parameter is a parameter related to a physical layer and affects operation at the physical layer. For example, PHY parameters that are configurable may include the system bandwidth, the uplink-downlink configuration if TDD is utilized, the number carriers configured for a UE, the number of antennas at a cell, etc. The PHY parameters may be broadcast in system information and may be received by UEs to determine the configuration of the cell and/or the wireless network. The UEs may then operate in accordance with the configuration of the cell and/or the wireless network.
In LTE, the MIB includes a dl-Bandwidth parameter that indicates the system bandwidth. LTE supports six possible system bandwidths of 1.4, 3, 5, 10, 15 or 20 megahertz (MHz). The dl-Bandwidth indicates a specific system bandwidth used by a cell and/or a wireless network from among the six possible system bandwidths. The system bandwidth may have a large impact on peak throughput.
In LTE, SIB1 includes a tdd-Config information element (IE) that indicates an uplink-downlink configuration for a wireless network utilizing TDD. LTE supports the seven uplink-downlink configurations shown in Table 1. The tdd-Config information element includes a subframeAssignment parameter that indicates a specific uplink-downlink configuration used by the wireless network from among the seven supported uplink-downlink configurations.
Other PHY parameters defining the configuration of a cell and/or a wireless network may also be sent in the MIB, SIB1, or other SIBs. Each PHY parameter may be sent in the MIB or a specific SIB, which may be transmitted at a periodicity indicated by the scheduling information carried in SIB1.
In general, a cell and/or a wireless network may have various configurable PHY parameters such as system bandwidth, uplink-downlink configuration, number of carriers, number of antennas, etc. The PHY parameters may be conveyed in system information and/or other signaling. Different system bandwidths, different uplink-downlink configurations, different numbers of carriers, and different numbers of antennas can support different throughputs for a UE.
In an aspect of the present disclosure, a UE may control and improve its operation based on PHY parameters obtained from a cell in a wireless network. The UE may receive system information broadcast by the cell and obtain the PHY parameters. The UE may provide the PHY parameters to one or more entities within the UE. Each entity may control certain operation of the UE such that good performance can be achieved.
A processing module 530 may process (e.g., descramble, decompress, etc.) the decoded data from PHY/modem processor 520. Processing module 530 may perform processing for layers above the physical layer. Processing module 530 may also perform functions and tasks normally not associated with the PHY layer, as described below.
For data transmission, processing module 530 may process data to be transmitted and provide output data to PHY/modem processor 520. Within PHY/modem processor 520, a transmit (TX) processor 524 may process (e.g., encode and modulate) the output data to obtain output samples. PHY/modem processor 520 may further convert the output samples to an analog output signal. A transmitter 514 may process (e.g., amplify, filter, and upconvert) the analog output signal to obtain an output RF signal, which may be transmitted via antenna 510 to eNBs and/or other stations.
In the design shown in
In the design shown in
A data processor/controller 580 may perform various functions for UE 120x. For example, data processor 580 may perform processing for data being transmitted and data being received by UE 120x. Controller 580 may control the operation of various processors, controllers, and other units within PHY/modem processor 520 and processing module 530. A memory 582 may store program codes and data for data processor/controller 580. The various processors and modules within UE 120x may communicate via a bus 590. Data processor/controller 580, memory 582, PHY/modem processor 520, and processing module 530 may be implemented on one or more application specific integrated circuits (ASICs) and/or other ICs.
As noted earlier,
A watermark controller 640 may receive the PHY parameters and may determine at least one watermark for each data buffer 630 in DSL 620. Watermark controller 640 may be part of memory and flow controller 540 in
In another design, watermark controller 640 may determine a single watermark for each data buffer 630 based on the PHY parameters. DSL 620 may not accept data from applications 574 when the amount of data in a given data buffer 630 exceeds the watermark. DSL 620 may accept data from applications 574 when the amount of data in the given data buffer 630 falls below the watermark.
In one design, watermark controller 640 may determine at least one watermark based on the PHY parameters. A higher watermark may be used for a wider system bandwidth (e.g., 20 MHz). Conversely, a lower watermark may be used for a more narrow system bandwidth (e.g., 1.4 MHz). In another design, watermark controller 640 may determine at least one watermark based on the uplink-downlink configuration. A higher uplink watermark may be used for an uplink-downlink configuration having more uplink subframes (e.g., uplink-downlink configuration 0 having six uplink subframes). Conversely, a lower uplink watermark may be used for an uplink-downlink configuration having fewer uplink subframes (e.g., uplink-downlink configuration 5 having one uplink subframe). In yet another design, watermark controller 640 may determine at least one watermark based on the number of carriers configured for UE 120. A higher watermark may be used for more carriers (e.g., five carriers). A lower watermark may be used for fewer carriers (e.g., one carrier). Watermark controller 640 may also determine at least one watermark based on any combination of the system bandwidth, the uplink-downlink configuration, the number of carriers configured for UE 120x, the number of antennas at a serving eNB, etc.
Conventionally, watermarks are set based on the largest system bandwidth of 20 MHz and uplink-downlink configuration 0 with the most number of uplink subframes. However, setting the watermarks based on the highest possible throughput on the uplink may result in sub-optimal performance for other network configurations. In particular, setting the watermarks too high may result in larger buffer sizes and may increase latency if the outflow is not fast enough. Conversely, setting the watermarks too low may result in smaller buffer sizes and may cause radio resources to be under-utilized. Setting the watermarks of data buffers 630 based on the PHY parameters, as described above, may improve performance.
Flow controller 554 may receive the PHY parameters and may generate controls for flows of different protocols (e.g., IP, PDCP and RLC) within data service layer 620. Data may be processed as flows within data service layer 620. A flow may refer to a stream of packets exchanged between a UE and an eNB. Flow controller 554 may generate controls for the flows based on the system bandwidth, the uplink-downlink configuration, the number of carriers, the number of antennas, etc. For example, flow controller 554 may generate control to increase the data rate or the throughput of a flow due to a wider system bandwidth, an uplink-downlink configuration with more uplink subframes, more carriers, more antennas, etc. Flow controller 554 may also redistribute resources to the flows based on the PHY parameters. For example, when the system bandwidth is narrow, flow controller 554 may ensure that a flow carrying control information can meet minimum requirements while reducing flows for traffic data and/or other information.
In one design, clock controller 550 may select clock rates based on the system bandwidth. Faster clocks may be generated for a wider system bandwidth, and slower clocks may be generated for a more narrow system bandwidth. In another design, clock controller 550 may select clock rates based on the uplink-downlink configuration. Faster TX clocks may be generated for more uplink subframes (e.g., in uplink-downlink configuration 0), and slower TX clocks may be generated for fewer uplink subframes (e.g., in uplink-downlink configuration 5). Faster RX clocks may be generated for more downlink subframes (e.g., in uplink-downlink configuration 5), and slower RX clocks may be generated for fewer downlink subframes (e.g., in uplink-downlink configuration 0). In yet another design, clock controller 550 may select clock rates based on the number of carriers configured for UE 120. Faster clocks may be generated for more carriers, and slower clocks may be generated for fewer carriers. In yet another design, clock controller 550 may select clock rates based on the number of antennas at the serving eNB. Faster clocks may be generated for more antennas, and slower clocks may be generated for fewer antennas. Clock controller 550 may select the clock rates for the TX clocks and/or the RX clocks based on any combination of the system bandwidth, the uplink-downlink configuration, the number of carriers configured for UE 120x, the number of antennas at a serving eNB, etc. Different clock rates may also be used for different tasks.
Conventionally, TX clocks and RX clocks are set based on the highest expected throughput on the uplink and downlink, respectively. This may coincide with the largest system bandwidth. The TX clocks may be set based further on uplink-downlink configuration 0 with the most uplink subframes. The RX clocks may be set based further on uplink-downlink configuration 5 with the most downlink subframes. Setting the TX clocks and RX clocks in this manner may ensure that these clocks are sufficiently fast even in the worst-case scenarios. However, setting the TX clocks and RX clocks based on the worst-case scenarios may result in excessively fast TX clocks and RX clocks in other scenarios. Controlling the clock rates of the TX clocks and/or the RX clocks based on the PHY parameters, as described above, may reduce power consumption, extend battery life, and provide other benefits.
In one design, thermal mitigator 560 may compare the sensed temperature against a single threshold. If the sensed temperature is higher than the threshold, then thermal mitigator 560 may initiate one or more remedial actions. In another design, thermal mitigator 560 may compare the sensed temperature against multiple thresholds and may initiate different remedial actions when the sensed temperature exceeds different thresholds. For example, the sensed temperature may be compared against a regular threshold, a critical threshold, and a danger threshold. Thermal mitigator 560 may initiate progressively more remedial actions and/or may perform the remedial actions more aggressively (e.g., reduce data rate more) in response to the sensed temperature exceeding progressively higher thresholds.
Various remedial actions may be performed based on the PHY parameters in order to reduce temperature of UE 120x. In one design, clock rates of TX clocks, RX clocks, and/or other clocks may be reduced in order to reduce power dissipation and lower the temperature of UE 120x. The clocks may be reduced based on the system bandwidth, the uplink-downlink configuration, the number of carriers, the number of antennas, etc. For example, the clock rates may be reduced more for a more narrow system bandwidth or reduced less for a wider system bandwidth in order to ensure that the clocks are sufficient fast for the system bandwidth.
In another design, applications and/or tasks requiring more central processing unit (CPU) may be identified based on their activity levels, their throughputs, and/or other criteria. One or more applications and/or tasks requiring more CPU may have their activity level or throughput reduced in order to lower the temperature of UE 120x. For example, the throughput or data rate of an application or a task requiring high CPU may be reduced when the system bandwidth is wide or may be cut when the system bandwidth is narrow.
In yet another design, the data rate of the uplink and/or the data rate of the downlink may be reduced based on the PHY parameters. For example, when high temperature is detected, the data rate on the uplink may be reduced when uplink-downlink configuration 0 with more uplink subframes than downlink subframes is utilized. The data rate on the downlink may be reduced when uplink-downlink configuration 5 with more downlink subframes than uplink subframes is utilized. Other remedial actions may also be performed in order to reduce the temperature of UE 120x.
Thermal mitigator 560 may generate various controls to reduce the temperature of UE 120x when high temperature is sensed. In one design, thermal mitigator 560 may generate controls to reduce the TX clocks, the RX clocks, and/or other clocks when high temperature is sensed. In another design, thermal mitigator 560 may generate controls to reduce the activity levels of one or more applications and/or tasks when high temperature is sensed. In yet another design, thermal mitigator 560 may generate controls to reduce the uplink data rate and/or the downlink data rate when high temperature is sensed. Thermal mitigator 560 may also generate controls for other remedial actions and/or a combination of remedial actions.
Controlling applications based on the PHY parameters may improve performance. In particular, applications may be executed with settings selected based on the PHY parameters (e.g., the system bandwidth and uplink-downlink configuration) so that the applications can provide good output and still be supported by UE 120x.
The techniques described herein may provide various advantages. First, the techniques may enable efficient use of resources at a UE to achieve good results based on PHY parameters. The techniques may improve data throughput, reduce power consumption, and provide better control of situations in case of bad network conditions. The techniques may be used for various wireless networks such as LTE, UMTS, CDMA 1X, GSM, and other wireless networks.
The UE may provide the at least one physical layer parameter to a third entity (e.g., clock controller 550 in
The UE may provide the at least one physical layer parameter to a fourth entity (e.g., thermal mitigator 560 in
The UE may provide the at least one physical layer parameter to a fifth entity (e.g., application controller 570 in
Apparatus 1300 comprises a central data bus 1302 linking several circuits together. The circuits include at least one processor 1304, a receive circuit 1306, a transmit circuit 1308, and a memory 1310. Memory 1310 is in electronic communication with processor(s) 1304, so that processor(s) 1304 may read information from and/or write information to memory 1310. Processor(s) 1304 may comprise a general purpose processor, a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a controller, a microcontroller, a state machine, an application specific integrated circuit (ASIC), a programmable logic device (PLD), a field programmable gate array (FPGA), etc. Processor(s) 1304 may comprise a combination of processing devices, e.g., 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.
Receive circuit 1306 and transmit circuit 1308 may be connected to a radio frequency (RF) circuit (not shown in
Memory 1310 stores a set of instructions 1312 executable by processor(s) 1304 to implement the methods described herein. To implement process 1100 in
Instructions 1312 shown in memory 1310 may comprise any type of computer-readable statement(s). For example, instructions 1312 in memory 1310 may refer to one or more programs, routines, sub-routines, modules, functions, procedures, data sets, etc. Instructions 1312 may comprise a single computer-readable statement or many computer-readable statements.
Memory 1310 may be a RAM (Random Access Memory) circuit. Memory 1310 may be tied to another memory circuit (not shown), which may either be of a volatile or a nonvolatile type. As an alternative, memory 1310 may be made of other circuit types, such as an EEPROM (Electrically Erasable Programmable Read Only Memory), an EPROM (Electrical Programmable Read Only Memory), a ROM (Read Only Memory), an ASIC (Application Specific Integrated Circuit), a magnetic disk, an optical disk, and others well known in the art. Memory 1310 may be considered to be an example of a computer-program product that comprises a computer-readable medium with instructions 1312 stored therein.
As noted earlier,
The previous description of the disclosure is presented to enable any person skilled in the art to make and use the disclosure. Details are set forth in the previous description for purpose of explanation. It should be appreciated that one of ordinary skill in the art would realize that the disclosure may be practiced without the use of these specific details. In other instances, well-known structures and processes are not elaborated in order not to obscure the description of the disclosure with unnecessary details. Thus, the present invention is not intended to be limited by the examples and designs described herein, but is to be accorded with the widest scope consistent with the principles and features disclosed herein.
The functions described herein may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored as one or more instructions on a computer-readable medium. The term “computer-readable medium” or “computer program product” refers to any tangible storage medium that can be accessed by a computer or a processor. By way of example, and not limitation, a computer-readable medium may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray® disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers.
Software or instructions may also be transmitted over a transmission medium. For example, if the software 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 transmission medium.
The methods disclosed herein comprise one or more steps or actions for achieving the described method. The method steps and/or actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is required for proper operation of the method that is being described, the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims.
It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes and variations may be made in the arrangement, operation and details of the networks, methods, and apparatus described herein without departing from the scope of the claims.
No claim element is to be construed under the provisions of 35 U.S.C. §112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.”
