1. Field
This application relates generally to communications, and more specifically, to ultra-wide band communication.
2. Background
Wireless technologies enable communications between devices and may be employed for a variety of applications associated with various wireless communication networks such as personal area network (“PAN”) and body area network (“BAN”). Synchronization of communications in such a network can consume substantial resources of a device. Thus, a need exists for alternative methods and apparatuses for communication synchronization.
A summary of sample aspects of the disclosure follows. For convenience, one or more aspects of the disclosure may be referred to herein simply as “some aspects.”
Method and apparatuses or devices of the invention each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of this invention, for example, as expressed by the claims which follow, its more prominent features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description” one will understand how the features of this invention provide advantages that include reduced consumption of power and/or other resources, for communication synchronization in, for example, an Ultra-wideband (UWB) network.
Some aspects include a method of communicating data. The method includes receiving information identifying at least one resource of a second electronic device, transmitting resource information of the electronic device, comparing the resource information of the electronic device and the received resource information of the second electronic device. The method may also include transmitting a synchronization signal to the second device based on the resource comparison. The method may also include receiving a synchronization signal from the second device subsequent to the resources comparison. Other aspects include systems, apparatuses, and devices for communicating data. For example, some aspects include devices such as headsets, watches, and medical devices configured to use such methods for communicating data.
The following detailed description is directed to certain specific aspects of the invention. However, the invention can be embodied in a multitude of different ways, for example, as defined and covered by the claims. It should be apparent that the aspects herein may be embodied in a wide variety of forms and that any specific structure, function, or both being disclosed herein is merely representative. Based on the teachings herein one skilled in the art should appreciate that an aspect disclosed herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, such an apparatus may be implemented or such a method may be practiced using other structure, functionality, or structure and functionality in addition to or other than one or more of the aspects set forth herein. As an example of some of the above concepts, in some aspects communication channels between devices may be based on pulse position modulation. In some aspects, communication channels between devices may be based on a convolutional coding. In some aspects, communication channels may be based on pulse position modulation and convolutional coding.
One or more of the devices 102 may detect the presence of the other devices 102 when the other devices 102 initially communicate over the link 106. Two or more devices 102 may be paired through an exchange of messages over the link 106. For example, two devices 102 may pair when one of the two devices 102 first detects (by receiving a message over the wireless link 106) the other device 102. The pairing process may be based at least partly on a user's authorization of the pairing. The paired group of the devices 102 may define a particular personal or body area network.
As discussed further below, in some aspects the communications link 106 has a pulse-based physical layer. For example, the physical layer may utilize ultra-wideband pulses that have a relatively short length (e.g., on the order of a few nanoseconds) and a relatively wide bandwidth. In some aspects, an ultra-wide band may be defined as having a fractional bandwidth on the order of approximately 20% or more and/or having a bandwidth on the order of approximately 500 MHz or more. The fractional bandwidth is a particular bandwidth associated with a device divided by its center frequency. For example, a device according to this disclosure may have a bandwidth of 1.75 GHz with center frequency 8.125 GHz and thus its fractional bandwidth is 1.75/8.125 or 21.5%.
Those skilled in the art would understand 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 referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.
The network interface 206 may include any suitable antenna (not shown), a receiver 220, and a transmitter 222 so that the exemplary device 102 can communicate with one or more devices over the wireless link 106. Optionally, the network interface 206 may also have processing capabilities to reduce processing requirements of the processor 202.
Optionally, the device 102 may include a second network interface 208 that communicates over the network 110 via a link 108. For example, the device 102 may provide connectivity to the other network 110 (e.g., a wide area network such as the Internet) via a wired or wireless communication link. Accordingly, the device 102 may enable other devices 102 (e.g., a Wi-Fi station) to access the other network 110. In addition, it should be appreciated that one or more of the devices 102 may be portable or, in some cases, relatively non-portable. The second network interface 208 may transmit and receive RF signals according to the IEEE 802.11 standard, including IEEE 802.11(a), (b), or (g), the BLUETOOTH standard, and/or CDMA, GSM, AMPS or other known signals that are used to communicate within a wireless cell phone network. In addition, the second network interface 208 may comprise any suitable wired network interface such as Ethernet (IEEE 802.3).
The device 102 may optionally include a battery 231 to provide power to one or more components of the device 102. The device 102 may comprise at least one of a mobile handset, a personal digital assistant, a laptop computer, a headset, a vehicle hands free device, or any other electronic device. In addition, the device 102 may comprise one or more of a biomedical sensor, biometric sensor, a pacemaker, or any other device for measuring or affecting a human body. In particular, the teachings herein may be incorporated into (e.g., implemented within or performed by) a variety of the devices 102. For example, one or more aspects taught herein may be incorporated into a phone (e.g., a cellular phone), a personal data assistant (“PDA”), an entertainment device (e.g., a music or video device), a headset (e.g., headphones, an earpiece, etc.), a microphone, a biometric sensor (e.g., a heart rate monitor, a pedometer, an EKG device, a keyboard, a mouse, etc.), a user I/O device (e.g., a watch, a remote control, a light switch, etc.), a tire pressure monitor, a computer, a point-of-sale device, an entertainment device, a hearing aid, a set-top box, or any other suitable device.
The components described herein may be implemented in a variety of ways. Referring to
As noted above,
In some aspects, the device or apparatus 102 may comprise an integrated circuit. Thus, the integrated circuit may comprise one or more processors that provide the functionality of the processor components illustrated in
The receiver 220 and the transmitter 222 may employ a variety of wireless physical layer schemes. For example, the physical layer 404 of the receiver 220 and the transmitter 222 may utilize some form of CDMA, TDMA, OFDM, OFDMA, or other modulation and multiplexing schemes.
Power and processor consumption during acquisition and synchronization between devices 102 in the system 100 can be substantial for devices 102 having a low duty cycle, e.g., a low duty cycle device (LDD). A low duty cycle device refers to a device that transmits or receives data only for a relatively small percentage of time that it is in operation. For example a health sensor, may have to execute the synchronization and acquisition operations very often compared to the amount of time it would otherwise be powered and operating. In some aspects, a method and apparatus are provided for reducing power and processor consumption for such acquisition and synchronization.
In one example of the system 100, a particular device 102 may comprise a network controller device (NCD), for example a cell phone. The NCD 102 may transmit a beacon comprising a synchronization signal at regular intervals. When a particular device 102, e.g., a LDD, wakes up, it searches for the beacon to synchronize to the system. To mitigate the effect of inaccuracies in timing, the LDD may have to operate a tracking loop to avoid too much drift. The associated cost in power and processing resources may be significant for some devices 102.
It is to be recognized that the designation of a particular device 102 as an NCD or an LDD is merely for purposes of description of the roles that devices 102 in the system 100 may perform. In particular, particular devices 102 may act as NCDs with respect to one or more other devices 102 and act as LDDs with respect to one or more other devices. Moreover, the roles of NCD and LDD devices may change over time based on changes in available resources. For example, an NCD and LDD may exchange roles when the battery of the NCD discharges beyond a specified level.
In particular, the devices 102 may transmit and receive messages indicative of resource information with other devices 102 in a particular system 100. Each device 102 may compare the resource information it receives from the other devices 102 with its own resource information to determine whether to act as a NCD or an LDD with reference to particular other devices. In one example of the system 100, such resource information is exchanged when the devices 102 are paired to define the system 100. In one example of the system 100, the resource information may also (or alternatively) be shared (and updated) periodically to allow devices 102 to change roles, for example, as their batteries discharge at different rates or as devices 102 are added or removed from the system 100.
Particular devices 102, e.g., NCDs, may have more lenient power and rate constraints than other devices 102 in the system 100. For example, a particular device 102 may comprise a LDD such as a health sensor that is configured to operate for a few months or year without change of battery. For such devices 102, it is desirable to transfer the burden of the synchronization procedure to other devices 102 including devices configured as NCDs.
In one example of the system 100, a particular device such as an LDD initiates a transmission procedure. For example, when the LDD 102 wakes up and has data to transfer or when it is woken up remotely by the another device 102 (e.g., a NCD), the LDD devices 102 sends a synchronization signal to the NCD 102 via the communication link 106. The synchronization signal may comprise a preamble sequence. The NCD 102 initiates acquisition and synchronization procedures and obtains the timing parameters of the LDD based on the preamble sequence.
In one example of the system 100, the NCD 102 may then regularly adjust its timing parameters to match the LDD parameters, thereby allowing the LDD 102 to continue transmitting without any timing parameter adjustments. In another example of the system 100, the NCD 102 may alternatively (or additionally) communicate regular timing updates to the LDD 102. In such examples of the system 100, the LDD 102 adjusts its timing parameters based on these updates. In one example of the system 100, the NCD 102 may communicate with multiple devices 102 including other LDDs 102 by maintaining multiple sets of timing data, e.g., a different set for each LDD.
After transmitting the synchronization signal, the LDD 102 may listen to the communications link 106 for a period of time in expectation of receiving an acknowledgement transmitted back using substantially the same timing parameters such as the timing offset. If it does not receive any valid response, it may go back to sleep, or repeat the message at a suitable interval.
After receiving the synchronization signal, the NCD 102 may transmit a message providing an offset to the LDD 102 to transmit at a different time offset. This message can instruct the LDD 102 to shift communication to a specific channel. Further, the NCD 102 may transmit messages providing data related to broadcast time based modes.
Moreover, the NCD 102 may provide channel and timing assignments to the LDD 102. The NCD 102 may provide timing data updates to the LDD 102 to reduce interference. In addition, the NCD 102 may assign channels to LDDs 102 that reduce interference when those LDDs 102 communicate concurrently with the NCD 102 or with other LDDs 102.
For illustration, the device 102A may be a NCD while devices 102B and 102C are LDDs. In operation in such a system, each of the devices 102B and 102C transmit their resource information to the device 102A. This resource information can be transmitted when the devices 102A, 102B, and 102C are paired and/or periodically. The device 102A may also transmit its resource information to one or both of the devices 102B and 102C. In one example of the system 100, each of the devices compares its resources to the received resources from the other devices 102 to determine which device transmits a synchronization signal and which should be configured to receive the synchronization signal. The device 102, e.g., device 102A, that is to receive the synchronization signal waits for a synchronization signal such as beacon signal to be transmitted by the device 102B. The device 102B may transmit the synchronization signal to resynchronize with the device 102A, e.g., after the device 102B has been in sleep mode.
In another example of the system 100, certain specified devices, e.g., NCD devices such as the device 102A, perform the comparison and provide instructions, e.g., at pairing, as to whether a particular LDD device such as LDD 102B and 102C should transmit synchronization signals or should be configured to receive such signals, e.g., from the NCD 102A.
In one example of the system 100, the LDDs 102B and 102C may be configured to communicate with each other via the wireless link 106B based on timing and other synchronization data provided by the NCD 102A. For example, both LDDs 102B and 102C may be configured to send synchronization signals to the NCD 102A to establish communication channels 106A and 106C. One or both of the LDDs 102B and 102C may be configured to receive timing and other synchronization information for their shared wireless link 106B from the NCD 102A via the wireless links 106A and 106C. In one example of the system 100, the NCD 102A is configured to transmit messages assigning one or more orthogonal or quasi-orthogonal channels having low interference to LDD devices 102B and 102C. The NCD device 102A can thus provide timing updates to the LDDs 102 to reduce interference in communications between the LDD devices 102A and 102B.
In some examples of the system 100, the NCD 102 may track the LDD 102 when there are many NCDs 102 receiving data from a particular LDD 102. For example, in one example system 100, a particular LDD may relay communications between two portions of a PAN (e.g., between two or more subnets) each having a different NCD 102. In such a system 100, the LDD 102 may determine that it is most efficient for it to generate synchronization and timing for communication to each of the NCDs 102. Thus, the LDD 102 transmits synchronization (e.g., beacon) signal to each of the NCDs 102. Each NCD receives a synchronization signal, performs a synchronization procedure based on the received signal, and tracks the timing of the LDD.
Accordingly, in some aspects, resource consumption associated with acquisition and synchronization can be shifted between devices 102 in the system 100, e.g., from devices 102 that have small power or other resource capabilities to more capable devices 102.
Moving to a block 606, the processor 202 compares the resource information of the electronic device and the received resource information of the second electronic device. For example, the processor 202 may compare resources and determine that the first electronic device has fewer of at least one resource than the second electronic device, e.g., fewer power resources in the form of less battery capacity or reserves. As noted above, the comparison may be performed once at pairing of the first and second devices 102 or each time the first and second devices 102 enter the system 100. Alternatively, or in addition, the devices 102 may exchange resource information periodically so that which device 102 has fewer resources may change over time. In another example, the processor 202 may use a multifactor or weighted comparison of resource information. For example, the comparison may be based on raw resource data (e.g., the battery capacity or reserves of each device), derived data based on resource data (e.g., battery lifetime based on duty cycle data of each device, or battery lifetime desired by each device in view of its duty cycle). Thus, for example, a health sensor device 102 may have a large battery capacity but a low expected duty cycle such that the comparison may identify the health sensor device 102 has fewer resources than a cell phone device 102 that has a similar battery capacity but a higher duty cycle.
In one example of the system 100, each of the first and second devices 102 performs the same or a corresponding comparison according to a predetermined protocol such that each device 102 determines whether to transmit or receive the synchronization signal. In another example, the comparison is performed during pairing, or when each of the devices 102 communicates, with data indicative of the results of the comparison communicated to each device 102 to determine which device 102 transmits and which device 102 receives the synchronization signal. In one example of the system 100, a third device 102 receives resource information of each of the first and second devices 102, performs the comparison, makes a determination as to which device 102 should transmit the synchronization signal and provides the devices 102 with that determination.
Proceeding to a block 608, the transmitter 222 transmits a synchronization signal to the second device subsequent to the comparing of block 606. For example, in one example of the system 100, maintaining timing data for communicating with a second electronic device may be costly in terms of power consumption and increased duty cycle to receive such data. A low duty cycle device 102 may reduce such overhead by transmitting a synchronization signal to another device 102 such that the receiving device 102 determines and maintains communication synchronization, e.g., configures itself to use the transmitters timing parameters. In such an example device, the transmitter 222 of the first device 102 may be configured to transmit the synchronization signal when the electronic device 102 has fewer power or battery resources than the second electronic device 102 and thus would benefit from reduced receiving and transmission overhead of maintaining timing synchronization with the second electronic device 102. The synchronization signal may include a beacon signal. The first device 102 may additionally receive and transmit data to the second device 102 based on timing and other synchronization data communicated or derived from the synchronization signal.
Moving to a block 706, the processor 202 compares the resource information of the electronic device and the received resource information of the second electronic device. For example, the processor 202 may determine that the first electronic device has more of at least one resource than the second electronic device, e.g., more power resources in the form of greater battery capacity or reserves. Proceeding to a block 708, the receiver 222 receives a synchronization signal from the second device subsequent to the comparing of block 606. For example, in one example of the system 100, maintaining timing or other synchronization data in the second electronic device may be costly in terms of power consumption and increased duty cycle to receive such data. A low duty cycle device 102 may reduce such overhead by transmitting a synchronization signal to another device 102 such that the receiving device 102 determines and maintains communication synchronization, e.g., configures itself to use the transmitters timing parameters. In such an example device, the receiver 220 of the receiving device 102 may be configured to receive the synchronization signal when the electronic device 102 has greater power or battery resources than the second electronic device 102 and thus overall system performance benefits from reduced receiving and transmission overhead of maintaining timing synchronization with the second electronic device 102. The synchronization signal may include a beacon signal. The receiving device 102 may additionally receive and transmit data to the second, e.g., low-duty cycle, device 102 based on timing and other synchronization data communicated or derived from the synchronization signal received from the second electronic device.
In view of the above, one will appreciate that the disclosure addresses how to communicate data, such as a UWB system. For example, the illustrated aspects provide a lower overhead method and apparatus of multi-hop communications. For example, power consumption on a low duty cycle device can be reduced by minimizing overhead for receiving and maintaining synchronization with other devices.
Any illustrative logical blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented within or performed by an integrated circuit (“IC”), an access terminal, or an access point. The IC may comprise 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, electrical components, optical components, mechanical components, or any combination thereof designed to perform the functions described herein, and may execute codes or instructions that reside within the IC, outside of the IC, or both. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing 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.
Those skilled in the art will recognize that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of this disclosure.
The steps of a method or algorithm described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, 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 the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.
While the above detailed description has shown, described, and pointed out novel features of the invention as applied to various aspects, it will be understood that various omissions, substitutions, and changes in the form and details of the device or process illustrated may be made by those skilled in the art without departing from the scope of this disclosure. As will be recognized, the invention may be embodied within a form that does not provide all of the features and benefits set forth herein, as some features may be used or practiced separately from others. The scope of this disclosure is defined by the appended claims, the foregoing description, or both. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
The present application for patent claims priority to U.S. Provisional Patent Application No. 60/795,512, entitled “LOW DUTY CYCLE DEVICE INITIATED TIMING SYNCHRONIZATION,” filed Apr. 26, 2006, assigned to the assignee hereof and hereby expressly incorporated by reference herein.
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