Patent Application
20140233608
This disclosure relates generally to location tracking, and more particularly to wireless location tracking of mobile devices.
Conventional systems use a single transmission of a longer duration that includes both the detection and identification of the beacon requiring a larger number of communications channels resulting in a higher network equipment cost and a higher network operating cost.
The above-mentioned shortcomings, disadvantages and problems are addressed herein, which will be understood by reading and studying the following specification.
The subject matter of this disclosure reduces the quantity of equipment, the deployment cost of the equipment, and the operating cost of the equipment required to support a large number of beacons used for the transfer of data from the beacon to the network from the network to the beacon and location of the beacon by the network, allows the use of the network to capture market needs that are currently not being serviced due to the cost of competing services that exceeds the value of the service to the customer and allows the use of the network to capture market needs that are currently being serviced by more costly services.
In one aspect, a computer-accessible medium having processor-executable instructions for wireless communication from a beacon to a network base station receiver, the processor-executable instructions capable of directing a processor to perform: transmitting a first here-i-am (HIA) transmission on a radio frequency channel of 12 radio frequency channels, transmitting a first registration (REG) transmission that is synchronized to the first HIA transmission on a radio frequency channel of 42 radio frequency channels, transmitting a second HIA transmission that is synchronized to the first REG transmission on a radio frequency channel of the 12 radio frequency channels, transmitting a second REG transmission that is synchronized to the second HIA transmission on a radio frequency channel of the 42 radio frequency channels, transmitting a third HIA transmission that is synchronized to the second REG transmission on a radio frequency channel of the 12 radio frequency channels, transmitting a third REG transmission that is synchronized to the third HIA transmission on a radio frequency channel of the 42 radio frequency channels, wherein each of the HIA transmissions is performed in accordance with a first pseudo-random frequency hopping pattern, the HIA transmission including: identification of a second radio frequency channel of 42 radio frequency channels, wherein the HIA transmission is a short transmission that does not include a serial number of the beacon, transmitting each of the REG transmissions that is synchronized to the immediately previous HIA transmission on the second pseudo-random frequency hopping pattern and in reference to the timing of the second pseudo-random frequency hopping pattern, the REG transmission that is synchronized to the immediately previous HIA transmission includes the serial number of the beacon, includes the information representative of a third pseudo-random frequency hopping pattern and includes the information representative of the timing of the third frequency hopping pattern, and transmitting a location tracking messaging (LOC) transmission on a radio frequency channel of the one of the plurality of the third pseudo-random frequency hopping patterns and in accordance with the timing of the frequency hopping patterns, the LOC transmission not including the information representative of the timing and information representative of the one of the plurality of the pseudo-random frequency hopping patterns, the transmitting of the LOC transmission is performed subsequent to the third REG transmission, wherein the 12 radio frequency channels and the 42 radio frequency channels are mutually exclusive and have no radio frequency channels in common between the 12 radio frequency channels and the 42 radio frequency channels.
In another aspect, a method of a beacon includes transmitting a first here-i-am (HIA) transmission, transmitting a first registration (REG) transmission that is synchronized to the first HIA transmission, transmitting a second HIA transmission that is synchronized to the first REG transmission, transmitting a second REG transmission that is synchronized to the second HIA transmission, transmitting a third HIA transmission that is synchronized to the second REG transmission, transmitting a third REG transmission that is synchronized to the third HIA transmission, wherein each of the HIA transmissions is performed to notify a network base station receiver that the beacon is in range of the network base station receiver to access the network base station receiver, to alert to the network base station receiver as to a presence of the beacon and to notify to the network base station receiver of a second radio frequency channel to transmit a registration (REG) transmission synchronized to the immediately previous HIA transmission, wherein each of the REG transmissions that is synchronized to the immediately previous HIA transmission on the second radio frequency channel includes a serial number of the beacon and includes information representative of timing and information representative of radio frequencies in a pseudo-random frequency hopping pattern, and transmitting a location tracking messaging (LOC) transmission after the third REG transmission on the radio frequencies in the plurality of the pseudo-random frequency hopping patterns and in accordance with the timing.
In yet another aspect, a computer-accessible medium includes a first component of processor-executable instructions to cause a first type of transmission from a beacon on a first radio frequency channel, the first transmission providing detection of the beacon by a network base station receiver, a second component of processor-executable instructions to cause a type of second transmission from the beacon on a second radio frequency channel synchronized to the first type of transmission, the second type of transmission identifying the beacon and including information that is necessary to grant network access by the network base station receiver to the beacon, and a third component to direct the first component to perform and then to direct the second component, at least twice in sequence.
Systems, clients, servers, methods, and computer-readable media of varying scope are described herein. In addition to the aspects and advantages described in this summary, further aspects and advantages will become apparent by reference to the drawings and by reading the detailed description that follows.
In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific implementations which may be practiced. These implementations are described in sufficient detail to enable those skilled in the art to practice the implementations, and it is to be understood that other implementations may be utilized and that logical, mechanical, electrical and other changes may be made without departing from the scope of the implementations. The following detailed description is, therefore, not to be taken in a limiting sense.
The detailed description is divided into five sections. In the first section, a system level overview is described. In the second section, implementations of apparatus are described. In the third section, implementations of methods are described. In the fourth section, hardware and the operating environments in conjunction with which implementations may be practiced are described. In the fourth section, implementations of the protocol are described. In the fifth section, a conclusion of the detailed description is provided.
System 100 includes a beacon 102 that is capable of transmitting a first type of message 104 on a first radio frequency channel 106. The first type of message 104 provides a notice to a network base station receiver 108 of the beacon 102. The beacon 102 is also capable thereafter of transmitting a second type of message 110 on a second radio frequency channel 112. The first type of message 110 provides to the network base station receiver 108 information that is necessary for the network base station receiver 108 to grant network access to the beacon 102, such as a pseudo-random frequency hopping pattern 114 and timing 116 of the pseudo-random frequency hopping pattern. The second radio frequency channel 112 is in the pseudo-random frequency hopping pattern 114. In addition, the second type of message 110 is synchronized to the first type of message 104 through the pseudo-random frequency hopping pattern 114 and the timing of the pseudo-random frequency hopping pattern 116 that are referenced by both the beacon 102 and the network base station receiver 108 in the transmission of the second type of message 110. In one example, the pseudo-random frequency hopping pattern 114 includes 42 radio frequencies.
In system 100, network access is bifurcated using two different transmissions (i.e. first type of message 104 and the second type of message 110) and two different communications channels (i.e. the first radio frequency 106 and the second radio frequency channel 112). The first type of message 104 provides the network with a means of detection of the beacon 102 that notifies the network of the presence of a beacon 102 and the intention of the beacon 102 to access the network. The second type of message 110 provides the network with a means to identify the beacon 102 and to receive additional information that may be necessary to grant network access to the beacon. By transmitting the beacon 102 identification and additional network access information in the second type of message 110 instead of the first type of message 104 permits the duration of the first type of message 104 to be reduced. In the case where the network is required to provide access to a large number of beacons 102, the reduction of the duration of the first type of message 104 allows the number of radio frequency channels that are used to initiate network access by a beacon 102 to be reduced. This reduction in the number of radio frequency channels used to initiate network access allows the number of network base station receivers 108 to be reduced resulting in a reduction in network equipment cost and network operating cost.
The first type of message 104 is a short transmission that does not include a serial number of the beacon 102. A large number of beacons 102 that require infrequent network access may share a small number of network resources and may gain access to the network resources when required. The use of only a small number of network resources is achieved by minimizing the duration of the transmission of the first type of message 104 by the beacon 102 required to notify the network of the intention of the beacon 102 to access the network. The shorter duration of the transmission of the first type of message 104 allows a large number of beacons 102 to be supported with a small number of radio frequency channels. With only a small number of radio frequency channels used, the cost to deploy and operate the network is reduced. A large number of beacons 102 that require infrequent access to the network of which the network base station receiver 108 is a part can share a small number of network resources and can gain access to the network resources when required. The use of only a small number of network resources is achieved by minimizing the duration of the transmission of the first type of message 104 by the beacon 102 that is required to notify the network of the intention of the beacon 102 to access the network. The shorter duration of the transmission of the first type of message 104 allows a large number of beacons 102 to be supported with a small number of radio frequency channels. With only a small number of radio frequency channels used, the cost to deploy and operate the network base station receiver 108 and the network to which the network base station receiver 108 is coupled is reduced.
In some implementations, the first message 104 is transmitted four times on different radio frequency channels by the beacon 102 and the second type of message 110 is transmitted two times by the beacon 102 in order to ensure receipt of the first type of message 104 and the second type of message 110 under circumstances where receipt of the first type of message 104 and the second type of message 110 is not known to the beacon 102 because the network base station receiver 108 does not send an acknowledgement of the first type of message 104 and the second type of message 110. The transmission of the first type of message 104 four times and the transmission of the second type of message 110 two times is reasonably calculated to ensure receipt of the first type of message 104 and the second type of message 110 by the network base station receiver 108 without an excessive number of unnecessary transmissions of the first type of message 104 and the second type of message 110.
In some implementations, the first type of message 104 is transmitted based on another pseudo-random frequency hopping pattern and timing of the other pseudo-random frequency hopping pattern that are stored in both the beacon 102 and the network base station receiver 108. In one example the other pseudo-random frequency hopping pattern has twelve radio frequencies.
The first type of message 104 is also known as an HIA transmission. The beacon 102 transmits in the HIA transmission an HIA burst. The HIA burst consists of four HIA mini-bursts. Each of the HIA mini-bursts notifies the network base station receiver 108 of the presence of the beacon 102 within range of the network base station receiver 108 and notifies the network base station receiver 108 that the beacon 102 will soon transmit a REG burst. A minimum of one network base station receiver 108 is required to receive at least one of the HIA.
The second type of message 110 is also known as a REG transmission. The beacon 102 is operable to transmit in the REG transmission a REG burst. The REG burst consists of two REG mini-bursts. The REG mini-bursts identify the beacon 102 by the serial number (WIN) of the beacon 102 and notify the network base station receiver 108 of the beacon 102's imminent transmission of either a series of LOC bursts or a series of SIM bursts or no additional bursts. A minimum of one network base station receiver 108 monitoring site is required to receive at least one of the REG mini-bursts.
In location tracking applications (
In telemetry applications (
While the system 100 is not limited to any particular beacon 102, a first type of message 104, a first radio frequency channel 106, receiver 108, a second type of message 110, a second radio frequency channel 112 and information 114 that is necessary for the network base station receiver to grant network access to the beacon 102, for sake of clarity a simplified beacon 102, first type of message 104, first radio frequency channel 106, receiver 108, second type of message 110, second radio frequency channel 112, pseudo-random frequency hopping pattern 114 and timing 116 of the pseudo-random frequency hopping pattern 116 are described. The network base station receiver 108 is also known as a base station.
Conventional techniques use a single transmission of a longer duration that includes both the detection and identification of the beacon 102, which requires a larger number of communications channels resulting in a higher network equipment cost and a higher network operating cost.
The system level overview of the operation of implementations is described above in this section of the detailed description. Some implementations can operate in a multi-processing, multi-threaded operating environment on a computer, such as general computer environment 1200 in
In the disclosure herein, the beacon 102 to the network base station receiver 108 are asynchronous because there is no synchronization between the beacon 102 and the network base station receiver 108. However, the transmissions between the beacon 102 and the network base station receiver 108 can be synchronized.
In
Referring to
The third type of message 202 is transmitted on a third radio frequency channel 210 of the second pseudo-random frequency hopping pattern 206 and the timing 208 of the pseudo-random frequency hopping pattern, and thus the third type of message 202 is synchronized to the second type of message 110 that are referenced by both the beacon 102 and the network base station receiver 108 in the transmission of the third type of message 202.
The third type of message 202 includes data 204. In some implementations, the data 204 includes application-specific data such as remote meter reading, smart grid, intelligent traffic signs, automotive, road condition telemetry, vending machine reporting and or/road construction equipment reporting. The third type of message 202 does not includes a serial number of the beacon 102, information representative of the radio frequencies of the pseudo-random frequency hopping patterns 114 and 206 or information representative of the timing 116 and 208 of the frequency hopping patterns.
Apparatus 200 provides exchange of information (i.e. data 204) from the beacon 102 to the network base station receiver 108 using a wireless communications channel (i.e. the third radio frequency channel 210) which has no conflict with the radio frequency channels (i.e. the first radio frequency channel 106 and the second radio frequency channel 112) over which communication between the beacon 102 and the network base station receiver 108 is established. The first type of message 104, the second type of message 110 and the third type of message 202 in the context of the protocol permits the beacon 102 to gain access to the network that the network base station receiver 108 that allows for the identification of the beacon 102 and allows for the transmission of data 204 from the beacon 102 to the network and from the network to the beacon.
In some implementations, the network base station receiver 108 is operable to transmit an acknowledgement to the beacon 102 after receiving the third type of message 202 and the beacon 102 is operable to attempt receipt of an acknowledgement transmission from the network base station receiver 108 after transmission of the third type of message 202 and the beacon 102 is operable to retransmit the first type of message 104, the second type of message 110 and the third type of message 202 when no acknowledgement transmission by the beacon 102 from the network base station receiver 108 is received after a period of time.
In some implementations, the beacon 102 is operable to transmit the first type of message 104 and the second type of message 110 without waiting or delaying any further operations for an acknowledgement message from the network base station receiver 108 of the first type of message 104 and the second type of message 110.
In some implementations, the first type of message 104 includes notice that the network base station receiver 108 is in range of the beacon 102 and the first type of message 104 includes a representation of imminent access to the beacon 102.
The third type of message 302 includes data 304. In some implementations, the data 304 is one of four types of location tracking (LOC) bursts: L0, L1, L2 or L3. The four LOC bursts are shown in Table 1. Each LOC burst consists of a combination of LOC Mini-bursts. There are three types of LOC Mini-bursts:
a. LOC Lower Mini-burst,
b. LOC Middle Mini-burst,
c. LOC Upper Mini-burst.
The beginning of the first LOC Middle Mini-burst in any one of the four LOC bursts is referred to as the LOC Sync Time.
The network base station receiver 108 determines the current location of the beacon 102 from the LOC burst transmissions, which provides the location tracking. In some implementations, the identification of the beacon 102 is be linked to the registration of the beacon 102 by way of the time of the LOC burst transmission and channel number of the LOC burst. The LOC bursts are as short as possible in order to maximize capacity of the system 300.
The third type of message 302 does not include a serial number of the beacon 102, information representative of the radio frequencies of the pseudo-random frequency hopping patterns 114 and 206 or information representative of the timing 116 and 208 of the frequency hopping patterns.
In some implementations, the network base station receiver 108 is operable to transmit an acknowledgement to the beacon 102 after receiving the third type of message 302 and the beacon 102 is operable to attempt receipt of an acknowledgement transmission from the network base station receiver 108 after transmission of the third type of message 302 and the beacon 102 is operable to retransmit first type of message 104, the second type of message 110 and the third type of message 302 when no acknowledgement transmission by the beacon 102 from the network base station receiver 108 is received after a period of time.
In some implementations, the beacon 102 is operable to transmit the first type of message 104 and the second type of message 110 without waiting or delaying any further operations for an acknowledgement message from the network base station receiver 108 of the first type of message 104 and the second type of message 110.
In implementations where the first type of message 104 of either apparatus 600 or apparatus 700 is transmitted based on the other pseudo-random frequency hopping pattern, the other pseudo-random frequency hopping pattern is known as the first pseudo-random frequency hopping pattern, the pseudo-random frequency hopping pattern 114 is known as the second pseudo-random frequency hopping pattern and the pseudo-random frequency hopping pattern 206 is known as the third pseudo-random frequency hopping pattern.
Apparatus components of the
In the previous section, a system level overview of the operation of an implementation is described. In this section, the particular methods of such an implementation are described by reference to a series of flowcharts. Describing the methods by reference to a flowchart enables one skilled in the art to develop such programs, firmware, or hardware, including such processor-executable instructions to carry out the methods on suitable computers, executing the processor-executable instructions from computer-readable media. Similarly, the methods performed by the server computer programs, firmware, or hardware are also composed of processor-executable instructions. Methods 800-1100 can be performed by a program executing on, or performed by firmware or hardware that is a part of, a computer, such as general computer environment 1200 in
Method 800 includes initializing a counter to zero, at block 801. Thereafter, method 800 includes transmitting a here-i-am (HIA) transmission from a beacon to a network base station receiver, at block 802. The HIA transmission is the first type of message 104 in
Method 800 includes transmitting the REG transmission, at block 804. The REG transmission is transmitted on one of the radio frequency channels in the second pseudo-random frequency hopping pattern, thus the REG transmission is synchronized to the HIA transmission on the second pseudo-random frequency hopping pattern. The REG transmission includes a serial number of beacon and a third pseudo-random frequency hopping pattern, such as 206 in
After the HIA and the REG transmissions, method 800 includes incrementing the counter by 1, at block 806, and then determining of the maximum number of iterations of pairs of HIA and REG transmissions has been performed, at block 808. If the maximum number of iterations of pairs of HIA and REG transmissions has not been performed, then the method continues at block 802. Otherwise, method 800 continues with transmitting a short-and-instant telemetry messaging (SIM) transmission, at block 810. The SIM transmission is transmitted on one of the radio frequency channels in the third pseudo-random frequency hopping pattern, thus the SIM transmission is synchronized to the REG transmission on the third pseudo-random frequency hopping pattern. The SIM transmission includes data, the data including application-specific data such as remote meter reading, smart grid, intelligent traffic signs, automotive, road condition telemetry, vending machine reporting, road construction equipment reporting, the data not including the serial number of the beacon. The data does not include the information representative of the timing and information representative of any of the pseudo-random frequency hopping patterns.
The radio frequency channels of the first, second and third pseudo-random frequency hopping patterns are mutually exclusive.
Method 900 includes initializing a counter to zero, at block 801. Thereafter, method 800 includes transmitting a here-i-am (HIA) transmission from a beacon to a network base station receiver, at block 802.
Method 900 includes transmitting the REG transmission, at block 804.
After the HIA and the REG transmissions, method 800 includes incrementing the counter by 1, at block 806, and then determining of the maximum number of iterations of pairs of HIA and REG transmissions has been performed, at block 808. If the maximum number of iterations of pairs of HIA and REG transmissions has not been performed, then the method continues at block 802. Otherwise, method 900 continues with transmitting a location messaging (LOC) transmission, at block 902. The LOC transmission is transmitted on one of the radio frequency channels in the third pseudo-random frequency hopping pattern, thus the LOC transmission is synchronized to the REG transmission on the third pseudo-random frequency hopping pattern. The LOC transmission includes one of the four types of location tracking (LOC) bursts. The data does not include the information representative of the timing or information representative of any of the pseudo-random frequency hopping patterns.
The radio frequency channels of the first, second and third pseudo-random frequency hopping patterns are mutually exclusive.
In
In
Method 1000 includes receiving a here-i-am (HIA) transmission at a network base station receiver, at block 1002. The HIA transmission is the first type of message 104 in
Method 1000 includes receiving the REG transmission, at block 1004. The REG transmission is received on one of the radio frequency channels in the second pseudo-random frequency hopping pattern, thus the REG transmission is synchronized to the HIA transmission on the second pseudo-random frequency hopping pattern. The REG transmission includes a serial number of beacon and a third pseudo-random frequency hopping pattern, such as 206 in
Method 1000 includes receiving a short-and-instant telemetry messaging (SIM) transmission, at block 1006. The SIM transmission is received on one of the radio frequency channels in the third pseudo-random frequency hopping pattern, thus the SIM transmission is synchronized to the REG transmission on the third pseudo-random frequency hopping pattern. The SIM transmission includes data, the data including application-specific data such as remote meter reading, smart grid, intelligent traffic signs, automotive, road condition telemetry, vending machine reporting, road construction equipment reporting, the data not including the serial number of the beacon. The data does not include the information representative of the timing and information representative of any of the pseudo-random frequency hopping patterns.
The radio frequency channels of the first, second and third pseudo-random frequency hopping patterns are mutually exclusive.
Method 1100 includes receiving a here-i-am (HIA) transmission at a network base station receiver, at block 1002.
Method 1100 includes receiving the REG transmission, at block 1004.
Method 1100 includes receiving a location messaging (LOC) transmission, at block 1106. The LOC transmission is transmitted on one of the radio frequency channels in the third pseudo-random frequency hopping pattern, thus the LOC transmission is synchronized to the REG transmission on the third pseudo-random frequency hopping pattern. The LOC transmission includes one of the four types of location tracking (LOC) bursts. The data does not include the information representative of the timing or information representative of any of the pseudo-random frequency hopping patterns.
In some implementations, methods 800-1100 are implemented as a sequence of processor-executable instructions which, when executed by a processor, such as processing units 1204 in
The illustrated operating environment 1200 is only one example of a suitable operating environment, and the example described with reference to
The computation resource 1202 includes one or more processors or processing units 1204, a system memory 1206, and a bus 1208 that couples various system components including the system memory 1206 to processor(s) 1204 and other elements in the environment 1200. The bus 1208 represents one or more of any of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port and a processor or local bus using any of a variety of bus architectures, and can be compatible with SCSI (small computer system interconnect), or other conventional bus architectures and protocols.
The system memory 1206 includes nonvolatile read-only memory (ROM) 1210 and random access memory (RAM) 1212, which can or can not include volatile memory elements. A basic input/output system (BIOS) 1214, containing the elementary routines that help to transfer information between elements within computation resource 1202 and with external items, typically invoked into operating memory during start-up, is stored in ROM 1210.
The computation resource 1202 further can include a non-volatile read/write memory 1216, represented in
The non-volatile read/write memory 1216 and associated computer-readable media provide nonvolatile storage of processor-readable instructions, data structures, program modules and other data for the computation resource 1202. Although the exemplary environment 1200 is described herein as employing a non-volatile read/write memory 1216, a removable magnetic disk 1220 and a removable optical disk 1226, it will be appreciated by those skilled in the art that other types of computer-readable media which can store data that is accessible by a computer, such as magnetic cassettes, FLASH memory cards, random access memories (RAMs), read only memories (ROM), and the like, can also be used in the exemplary operating environment.
A number of program modules can be stored via the non-volatile read/write memory 1216, magnetic disk 1220, optical disk 1226, ROM 1210, or RAM 1212, including an operating system 1230, one or more application programs 1232, other program modules 1234 and program data 1236. Examples of computer operating systems conventionally employed for some types of three-dimensional and/or two-dimensional medical image data include the NUCLEUS® operating system, the LINUX® operating system, and others, for example, providing capability for supporting application programs 1232 using, for example, code modules written in the C++® computer programming language.
A user can enter commands and information into computation resource 1202 through input devices such as input media 1238 (e.g., keyboard/keypad, tactile input or pointing device, mouse, foot-operated switching apparatus, joystick, touchscreen or touchpad, microphone, antenna etc.). Such input devices 1238 are coupled to the processing unit 1204 through a conventional input/output interface 1242 that is, in turn, coupled to the system bus. A monitor 1250 or other type of display device is also coupled to the system bus 1208 via an interface, such as a video adapter 1252.
The computation resource 1202 can include capability for operating in a networked environment using logical connections to one or more remote computers, such as a remote computer 1260. The remote computer 1260 can be a personal computer, a server, a router, a network PC, a peer device or other common network node, and typically includes many or all of the elements described above relative to the computation resource 1202. In a networked environment, program modules depicted relative to the computation resource 1202, or portions thereof, can be stored in a remote memory storage device such as can be associated with the remote computer 1260. By way of example, remote application programs 1262 reside on a memory device of the remote computer 1260. The logical connections represented in
Such networking environments are commonplace in modern computer systems, and in association with intranets and the Internet. In certain implementations, the computation resource 1202 executes an Internet Web browser program (which can optionally be integrated into the operating system 1230), such as the “Internet Explorer®” Web browser manufactured and distributed by the Microsoft Corporation of Redmond, Wash.
When used in a LAN-coupled environment, the computation resource 1202 communicates with or through the local area network 1272 via a network interface or adapter 1276. When used in a WAN-coupled environment, the computation resource 1202 typically includes interfaces, such as a modem 1278, or other apparatus, for establishing communications with or through the WAN 1274, such as the Internet. The modem 1278, which can be internal or external, is coupled to the system bus 1208 via a serial port interface.
In a networked environment, program modules depicted relative to the computation resource 1202, or portions thereof, can be stored in remote memory apparatus. It will be appreciated that the network connections shown are exemplary, and other means of establishing a communications link between various computer systems and elements can be used.
A user of a computer can operate in a networked environment using logical connections to one or more remote computers, such as a remote computer 1260, which can be a personal computer, a server, a router, a network PC, a peer device or other common network node. Typically, a remote computer 1260 includes many or all of the elements described above relative to the computer 1200 of
The computation resource 1202 typically includes at least some form of computer-readable media. Computer-readable media can be any available media that can be accessed by the computation resource 1202. By way of example, and not limitation, computer-readable media can comprise computer storage media and communication media.
Computer storage media include volatile and nonvolatile, removable and non-removable media, implemented in any method or technology for storage of information, such as processor-readable instructions, data structures, program modules or other data. The term “computer storage media” includes, but is not limited to, RAM, ROM, EEPROM, FLASH memory or other memory technology, CD, DVD, or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other media which can be used to store computer-intelligible information and which can be accessed by the computation resource 1202.
Communication media typically embodies processor-executable instructions, data structures, program modules or other data, represented via, and determinable from, a modulated data signal, such as a carrier wave or other transport mechanism, and includes any information delivery media. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal in a fashion amenable to computer interpretation.
By way of example, and not limitation, communication media include wired media, such as wired network or direct-wired connections, and wireless media, such as acoustic, RF, infrared and other wireless media. The scope of the term computer-readable media includes combinations of any of the above.
Various implementations of the protocol are described without limiting this disclosure.
Each HIA burst indicates an upcoming transmission of a REG burst. Each HIA burst includes of four HIA mini-bursts. Each HIA mini-burst includes of two parts, a 16.384 ms detection burst followed by a data burst. The Detection burst can be used by the network to detect the beginning of the HIA Mini-Burs. In an HIA mini-burst, the Data burst consists of one HIA Data burst with duration of 16.384 ms. The Data burst contains 8 data bits: two bits are used to determine the type of mini-burst: HIA (00b) while the remaining 6 bits are used to transmit the Channel Sequence number (CSN).
Regardless of the type of mini-burst that is utilized by the HIA, the selection of the channels are pseudo-random. The HIA channel number in combination with the Channel Sequence number are used to identify which of the mini-bursts has been received. This information are used to determine the time at which the REG burst may be received. The Channel Sequence number is used to determine the REG mini-burst channel hopping pattern.
Each of the four HIA mini-bursts is transmitted sequentially with a 38.0 ms delay measured from the beginning of one HIA mini-burst to the beginning of the next HIA mini-burst. Each HIA mini-burst includes of two parts, a 16.384 ms Detection burst followed by one 16.384 ms HIA Data burst. The beginning of the first HIA mini-burst is referred to as HIA Sync Time.
The beacon 102 is operable to transmit a REG burst. The REG burst includes of two REG mini-bursts. Each of the two mini-bursts are transmitted sequentially with a 2 second delay measured from the beginning of the first mini-burst to the beginning of the second mini-burst. The selection of the REG channels is pseudo-random.
The Network is operable to assign radios, as necessary, to tune to the required registration channel at the required time to receive the REG mini-bursts. While the REG mini-burst is longer in duration than the HIA mini-burst, the required number of deployed radios is reduced by the fact that the channels are only monitored on an as-needed basis.
Each REG mini-burst includes of a 196.608 millisecond REG Data burst, containing the following encoded information:
The beacon 102 Identification Number (WIN) uniquely identifies the transmitting beacon 102. The network base station receiver 108 is operable to use this information to correctly interpret the identity and application of the transmitting beacon 102. No two beacons 102 have the same WIN.
The Data Messages component is used for application specific data and is defined by the application and by the Data Class. The Data Class (4 bits long) defines how the bits in the Data Message are interpreted. Several Data Classes have been developed so far.
The LOC burst used in the tracking application includes of one of the four types of LOC bursts: L0, L1, L2 or L3. Each LOC burst consists of a combination of LOC mini-bursts. There are three types of LOC mini-bursts:
LOC Lower mini-burst,
LOC Middle mini-burst,
LOC Upper mini-burst.
Each LOC burst are transmitted on one of the locate channels. The selection of the locate channels are pseudo-random. The beginning of the first LOC Middle Mini-burst in any one of the four LOC bursts is referred to as the LOC Sync Time.
The network base station receiver 108 is operable to use the beacon 102's LOC burst transmissions to determine the location of the beacon 102. The identification of the beacon 102 can be linked to the beacon 102's registration by way of the time of the LOC burst transmission and channel number of the LOC burst. The LOC bursts are kept as short as possible in order to maximize the network base station receiver 108 capacity.
The SIM uplink transmission is able to carry up to 260 bytes of data. The data are partitioned into 9-byte blocks. If the length of the data, in bytes, is not an integer multiple of 9, then a sufficient number of bytes with a value of 0x00 are appended at the end.
Next, each block is encoded according to Reed-Solomon coding, to form a SIM burst. Putting all the SIM bursts together forms a SIM Packet as shown in
Each SIM Packet includes of as many SIM bursts as necessary to transmit the data as shown in
Each SIM burst includes of 2 SIM mini-bursts.
The Tracking application uses a LOC burst consisting of one of four
locate bursts: L0 burst, L1 burst, L2 burst or L3 burst.
The transmission sequence and timing for L0 are as follows (all delays measured from start of preceding mini-burst to start of next mini-burst).
LOC Sync Time Transmit first LOC Middle mini-burst of duration 16.384 ms
The transmission sequence and timing for L1 are as follows (all delays measured from start of preceding mini-burst to start of next mini-burst).
Transmit first LOC Upper mini-burst of duration 16.384 ms
Transmit first LOC Lower mini-burst of duration 16.384 ms
delay 24.576 ms
LOC Sync Time Transmit first LOC Middle mini-burst of duration 16.384 ms
The transmission sequence and timing for L2 are as follows (all delays measured from start of preceding mini-burst to start of next mini-burst).
Transmit first LOC Upper mini-burst of duration 16.384 ms
Transmit first LOC Lower mini-burst of duration 16.384 ms
delay 24.576 ms
LOC Sync Time Transmit first LOC Middle mini-burst of duration 16.384 ms
delay 24.576 ms
Transmit second LOC Middle mini-burst of duration 16.384 ms
Transmit third LOC Middle mini-burst of duration 16.384 ms
The transmission sequence and timing for L3 are as follows (all delays measured from start of preceding mini-burst to start of next mini-burst).
Transmit first LOC Upper mini-burst of duration 16.384 ms
Transmit first LOC Lower mini-burst of duration 16.384 ms
delay 24.576 ms
Loc Sync Time Transmit first LOC Middle mini-burst of duration 16.384 ms
delay 24.576 ms
Transmit second LOC Middle mini-burst of duration 16.384 ms
Transmit third LOC Middle mini-burst of duration 16.384 ms
Transmit fourth LOC Middle mini-burst of duration 16.384 ms
Transmit fifth LOC Middle mini-burst of duration 16.384 ms
Transmit sixth LOC Middle mini-burst of duration 16.384 ms
Transmit seventh LOC Middle mini-burst of duration 16.384 ms
Transmit eighth LOC Middle mini-burst of duration 16.384 ms
The transmission sequence and timing for a SIM Packet are described as follows (all delays measured from start of preceding SIM mini-burst to start of next SIM mini-burst).
SIM Sync Time
Transmit SIM mini-burst1,1 of duration 393.216 ms
delay 0.5 seconds
Transmit SIM mini-burst2,1 of duration 393.216 ms
delay 0.5 seconds
. . . continue transmission of all the SIM mini-burstsi,1 (i=3, 4, . . . , #S) and their corresponding delays
Transmit SIM mini-burst1,2 of duration 393.216 ms
delay 0.5 seconds
Transmit SIM mini-burst2,2 of duration 393.216 ms
delay 0.5 seconds
. . . continue transmission of all the SIM mini-burstsi,2 (i=3, 4, . . . , #S) and their corresponding delays
where SIM mini-burstsi,1 denotes the first SIM mini-burst of the ith SIM burst, i.e. SIM bursti, and SIM mini-burstsi,2 denotes the second SIM mini-burst of the ith SIM burst.
In order to increase the utilization of the bandwidth available in the 2400 MHz ISM band, the HIA, REG and SIM channels are allocated a bandwidth of 62.5 kHz each while the LOC channels are allocated a bandwidth of 250 kHz. The ISM 3 channels are allocated at a spacing of 31.25 kHz and carefully chosen to allow the channels to be interleaved. Due to the bandwidth of the HIA, REG, LOC, and SIM signals and the allowable variations in carrier frequency the HIA, REG, LOC, and SIM signals may fall outside of the allocated channels.
Some of the channels located near the 2400 MHz band edge and some of the channels located near the 2483.5 MHz band edge are left unused to serve as a guard band to assist in the compliance with the radio transmitter regulations. Leaving a 937.5 kHz guard band on the lower band edge of the 2400 MHz ISM band and a 1000 kHz guard band on the upper band edge, and designating the lowest possible RF Channel as 1::
fRF=2400.9375 MHz+N(0.03125 MHz) Equation 1
Where:
N=[1, . . . ,2639] Equation 2
The distribution of these channels among the different logical channels are as follows:
12 HIA channels,
42 REG channels (paired in groups of two),
84 SIM channels (paired in groups of two),
245 LOC channels1,
123 Reserved channels.
The 12 HIA channels have been divided into four groups of three HIA channels each. The groups are known as HIA group A, HIA group B, HIA group C, and HIA group D. The HIA channels are designated HIA channel A1, A2, A3, B1, B2, B3, C1, C2, C3, D1, D2 and D3.
When the beacon 102 transmits the four consecutive HIA mini-bursts, each one of the four HIA mini-bursts are transmitted on a different HIA channel group (either group A, B, C, or D), where the order of the groups and the channel number within the group are pseudo-randomly selected. The network base station receiver 108 network is operable to continuously monitor the HIA channels and to receive the HIA mini-bursts. By decoding the Channel Sequence number within the HIA mini-burst and knowing the channel group on which the HIA mini-burst was received the Network is able to determine which of the four HIA mini-bursts was received (first, second, third or fourth). By knowing the transmission time of the HIA mini-bursts and by knowing which of the four HIA was received (first, second, third or fourth), the time of the Registration burst and the time of the Locate bursts can be determined. By decoding the Channel Sequence number within the HIA mini-burst, the channel number for each of the Registration mini-bursts can be determined. An additional 16 Locate channels are deemed unusable due to FCC emission constraints.
The HIA channels are used in such a manner that the HIA mini-bursts are uniformly distributed among the 12 HIA channels. The HIA transmission channel sequence conforms to the following requirements:
Each HIA burst uses one channel from each of the HIA channel groups (i.e. the four HIA mini-bursts use one channel from group A, one channel from group B, one channel from group C and one channel from group D).
The order in which the channel groups are used are pseudo-randomly selected and change from one HIA burst to the next.
The channel number within each group follow a pseudo-random sequence based upon the beacon 102's WIN. Each channel number of each channel group are used in any group of 3 REG (i.e. the pattern repeats every 12 HIA transmissions).
The CSN are initialized according to the formula given in (3.3). The Channel Sequence number (CSN) are incremented for each HIA burst by a simple linear congruent generator (LCG), which is of the format CSNi+1=(a×CSNi+b) mod 64. The LCG are assigned from the 6 LSBs of the WIN, and the initial CSN value (i.e. CSN0); or seed, are determined by Equation 3.3 on power-up.
The CSNNLNS are initialized according to the formula given in (3.3). The CSNNLNS are incremented for each No LOC/No SIM HIA burst by a simple linear congruent generator (LCG), which is of the format CSNi+1=(a×CSNi+b) mod 64. The beacon 102 specifications may require that certain No LOC/No SIM's use specific CSNs that may require deviations to the No LOC/No SIM CSN sequence specified in this paragraph.
CSN0={WINH⊕[(WINL&0x0FFF)<<1]}mod64 Equation 3
Where {WINH, WINL} denote the upper and lower 16 bits of the WIN respectively, & denotes the bit-wise and operator, ⊕ denotes the bit-wise exclusive-or operator, and <<n denotes an n-bit shift to the left (i.e. multiplication by 2n).
The 12 channels reserved for HIA have been carefully chosen so as to minimize the effects of interference and to maximize system availability. The HIA channel numbers and frequencies are as follows in table 2:
The following relations give the carrier frequency of the HIA channels based upon the subscript index k.
f
HIA(Ak)=[77125+210×[3(k−1)+└k>>1┘]]×31250
f
HIA(Bk)=[76495+420k]×31250
f
HIA(Ck)=[77965+420k]×31250
f
HIA(Dk)=[77545+210×[4(k−1)−└k>>1┘]]×31250 Equation 4
Where └•┘ denotes integer truncation; i.e. rounding down to the nearest integer value, and >>n denotes an n-bit shift to the right (i.e. multiplication by 2-n).
In some implementations, when the beacon 102 transmits a REG burst, the beacon 102 will always transmit two identical mini-bursts. Each of the two REG are transmitted on a different REG channel. The network base station receiver 108 is operable to use the timing information and channel information obtained from any one of the four HIA mini-bursts to tune a portion of the Network to the specified channel at the specified time in order to receive one of the two REG. In the event that the Network fails to receive the first REG, the Network may repeat the process and attempt to receive the second REG. Each REG contains the WIN. By using the WIN and the Channel Sequence number as a seed for a pseudo-random sequence the Network is able to determine the sequence of channels that the beacon 102 will use for the LOC bursts. The timing for the LOC bursts can be derived either from the timing of the HIA.
The channels used are selected such that a large number of beacons 102102 use the REG channels in such a manner that the REG mini-bursts are uniformly distributed among the 42 REG channels. The REG transmission channel sequence conforms to the following requirements:
Each REG mini-burst uses a different REG channel.
The REG channel patterns are selected based upon the CSN (or CSNNLNS), where the CSN sequence is determined by the assigned LCG.
The following equation determines the carrier frequency for the ISM 3 REG channels based upon the subscript index k of Table 2.
f
REG(Rk)=[76857+60k]×31250 Equation 5
The network base station receiver 108 is operable to use the timing information and channel information obtained from either the HIA mini-bursts and from either the REG mini-bursts to tune a portion of the Network to the specified channel at the specified time in order to receive the LOC burst.
The channels used are selected such that a large number of beacons 102102 use the LOC channels in such a manner that the LOC bursts are uniformly distributed among the LOC channels. The LOC transmission channel sequence conforms to the requirements for unlicensed radio transmitter operation.
The 245 channels reserved for the LOC waveform have been carefully chosen so as to minimize the effects of interference and to maximize system availability. The LOC channel numbers and frequencies are provided in Table 3. Initially, 261 channels are designated, however, 21 channels are not be used due to FCC emission constraints. i.e. ISM 3 LOC channels {0-2, 243-260}.
The following equation determines the carrier frequency for the ISM 3 LOC channels based upon the subscript index k of the Table 4, i.e. ISM 3 LOC Channel column of Table 4.
The modulus of the index k (i.e. k modulo 3 or k mod 3) can be determined by division or by iterative reduction, i.e. subtracting the modulus until k<3. The division approach may not be viable if the beacon 102's microprocessor does not support division, and the iterative step decrement is not efficient. A rapid and efficient method to determine the modulus is beneficial such that critical timing intervals maintained by the beacon 102 are not jeopardized. A reduced number of iterations can be achieved by using the following property (i.e. Mersenne numbers).
k mod(2n−1)=(k mod 2n+k>>n)mod(2n−1). Equation 6
Therefore, to obtain k mod 3:
where & denotes the bit-wise and operator.
If the right hand side (rhs) of Eqn 7; i.e. (k & 0x0003+k>>2), yields a result≧22−1 then an iterative reduction (i.e. subtracting 22−1=3). Since k spans [1, . . . , 245]; is performed implying that the rhs of Eqn 7 spans [0, . . . , 62], significant iterative reduction can still occur. However, Equation 3.8 can be iteratively applied to each resulting rhs to perform the reduction.
For example, let k=245=0x00F5, which given that 245 mod 3=2. Applying Equation 3.8 iteratively, the following is obtained:
245 mod 3=(0x00F5&0x0003+245>>2)mod 3
=62 mod 3
62 mod 3=(0x003E&0x0003+62>>2)mod 3
=17 mod 3
17 mod 3=(0x0011&0x0003+17>>2)mod 3
=5 mod 3
5 mod 3=(0x0005&0x0003+5>>2)mod 3
=2 mod 3
245 mod 3=2
Note that if applying this method and the rhs=3, iterative reduction by using Equation 3.8 can result in an infinite loop since (3 & 0x0003+3>>2)=3
The channels used are selected such that a large number of beacons 102102 use the SIM channels in such a manner that the SIM mini-bursts are uniformly distributed among the SIM channels. The SIM transmission channel sequence conforms to the requirements for unlicensed radio transmitter operation.
There are 84 channels for use by SIM. These channels have been chosen so as to reduce the effects of interference and to improve system availability. The channels used by SIM are listed in Table 5.
The following equation determines the carrier frequency for the ISM 3 SIM channels based upon the subscript index k of the Table 5.
f
SIM(Mk)=[76889+30k]×31250
The sub-channels in the HIA groupings {A, B, C, D} have a period of three, which ensures that each of the frequencies of each individual sub-group is transmitted in any three consecutive REG periods. This restricts the randomness of the selection of sub-channels selected per group in any time interval. i.e.
per group {A, B, C, D} in the first registration interval, then
for the second interval, and
for the third interval.
For example, for HIA group A, the set {1, 2, 3} can be a starting point. If 3 is selected for the first interval, then the next interval is restricted to the set {1, 2} for HIA A. If 1 is then selected, then for the third interval 2 are used for HIA A. Thus, the HIA A pattern becomes {A3, A1, A2}.
The HIA grouping pattern based on the CSN follows that outlined in Table 6, which contains the HIA and REG channel sequences for the corresponding Channel Sequence number.
The HIA sub-channel selection can only generate two possible sequences, i.e. {1, 2, 3, 1, . . . } and {1, 3, 2, 1, . . . }. Therefore, sequence {1, 2, 3, . . . } and {1, 3, 2, . . . } are denoted as HIA sub-sequence 0 and 1 respectively.
For HIA groups {A, B, C, D}, the corresponding sub-sequence are determined by bits {W(9), W(10), W(11), W(12)} of the 32-bit WIN, where W(0) represents the least significant bit (LSB) of the WIN. The HIA sub-sequences can easily be generated in the following manner.
The initial or starting seed for each HIA sequence are determined upon power-up of the beacon 102, where the 8 LSBs are paired in the following method.
For example, let WIN=5695785=0x0056 E929.
The 8 LSBs of the WIN are b#0010 1001, thus, the initial seed of the HIA groups {A, B, C, D} are y0+1={2, 3, 3, 1} respectively. Similarly, {W(9), W(10), W(11), W(12)}={0, 0, 1, 0}. Therefore, HIA groups {A, B, C, D} will use sub-sequences {0, 0, 1, 0} respectively.
Thus, the consecutive sub channel numbering per HIA group upon power-up is then as follows:
Table 6 can be partitioned into two regions, where the REG channel pairs {RX,RY} are easily determined by the following relationships.
For example, if CSN=0x2D=45, then X=(45−27)=18, and Y=18+13=31.
Thus, the corresponding REG channel pair is {RX,RY}={R18,R31}.
The selection of channels is both uniform and reproducible. Uniform specifies that all resources (i.e. all available channels) residing in the designated channel pool are used equally on average. This is required in order to minimize collisions, where collisions are contention of the same RF channel frequency by more than one user. Although there is inherently some time diversity in the system, where the probability of multiple users occupying the same RF channel frequency is low, however, as the number of users increase then the probability of collisions will increase.
Reproducible specifies that both the ISM 3 beacon 102 (including future versions) and the ISM 3 receivers (via the Network) can both reproduce the ordered selection of resources from common information known to both.
Using an n-bit linear feedback shift register (LFSR) implementation of a M-sequence; which guarantees a period of 2n−1, provides a viable method for selecting the hop pattern of LOC transmission sequences. Thus, one can select a suitable PN sequence with a long cyclic period; however, the number of resources N (i.e. number of available channels dedicated to LOC transmissions) either directly or indirectly restricts the period. For example, one can take m consecutive clocked bits of the output sequence to select the resources, where N≦2m. However, the sub-sequences of the long M-sequence do not guarantee a period of 2n−1.
In order to maintain a unique code phase of the M-sequence for every beacon 102, the 32-bit WIN and 6-bit CSN are used as the initial state for the LFSR. This implies that ≧38-degree primitive polynomial is required to implement as a LFSR. Implementing a 38-degree polynomial is feasible on the beacon 102's 16-bit microprocessor. The primitive polynomial f(x)=x38+x6+x5+x+1 are used.
It should be noted that there are two possible LFSR configurations, Fibonacci and Galois. The Fibonacci configuration is suitable for gate implementation in hardware devices (i.e. programmable logic devices), while the Galois configuration is well suited for software implementation. Galois configuration is illustrated in
For the Galois configuration, the reciprocal polynomial f*(x)=x38+x37+x33+x32+1 are implemented.
There are 245; i.e. [1, . . . , 245], usable LOC channels. When the mini-burst feature is enabled; which has consecutive LOC transmissions spaced at ±937.5 kHz of the previous designated LOC channel, the resources become further restricted to Locate channels [3, . . . , 242] due to the FCC emission constraints. This requires an 8-bit mask, with extra conditional checks to determine if the generated channel is valid (i.e. 3≦channel≦242). Thus, rather than collecting 8 consecutive clocked output MSBs of the LFSR to generate a possible LOC channel, the same generated value can be obtained from the 8 LSBs of the state register of the Galois configuration.
If the generated LOC channel is deemed to be invalid, then the state register is clocked an additional 8 times per generated channel. Unfortunately, this adds some processing cycle uncertainty, since every generated channel requires validity checks and the process continues until a valid channel is generated.
Therefore, the LOC channel sequence generation is as follows:
The LFSR spans three 16-bit words, where a single clock/shift of the LFSR can be accomplished in a similar manner as the pseudo code provided below.
It should be noted that this hop function is not sophisticated, especially if one is a cryptanalyst. This function was chosen for implementation ease of the function in the beacon 102 and uniformity of resource selection.
For example, let CSN=61=0x3D for the current Registration period, and WIN=5695785=0x0056 E929.
Therefore, the initial seed of the LFSR state register is
LFSR=[00000000010101101110100100101001111101],
=0x00 15BA 4A7D
and after 38 clocks (to ensure some randomization of initial seed), then:
LFSR=[11001000011001111000110110100011101110]
=0x32 19E3 68EE.
When 20 consecutive LOC channels are generated, i.e. k=[1, 2, . . . , 20], for a REG period; neglecting two LOC mini-bursts, the following is obtained:
It may be noted that LOC channels 229 and 139 are both repeated once, and the maximum number of possible channels generated per valid channel is two in this instance.
An LFSR implementation of a ML-sequence which ensures a uniform selection of all the SIM channels, similar to the one used to generate the LOC channels frequency hopping pattern, are used. The LFSR uses the generator polynomial:
f′(x)=x38+x37+x33+x32+1
to generate the SIM channel hop pattern. The 32-bit WIN and 6-bit CSN are used as the initial state for the LFSR, i.e. LFSR0=[(WIN<<6)⊕CSN clocked 38 times].
The LFSR are clocked 6 times to generate an index (less than 64) called “SIM burst channel index” for selecting a pair of SIM channels to be utilized by SIM mini-burst1 and SIM mini-burst2. That index are obtained only by considering the 6 LSB's of the state register of the Galois configuration which is well suited for software development of LFSR's.
As an example, let CSN=61=0x3D and WIN=123456789=0x075BCD15.
Therefore, the SIM LFER state register is preloaded as
LFSR=[00,0001,1101,0110,1111,0011,0100,0101,0111,1101]b,
And the initial seed of the SIM LFSR state register (after 38 clocks) is
LFSR=[10,0100,0110,1111,1101,1100,1001,1101,0100,0011]b =0x24 6FDC 9D43.
When 32 consecutive SIM burst channel indices, i.e. k=[1, 2, . . . , 32] are generated, to be used by SIM bursts which belong to a SIM Packet, obtain the SIM burst channel indices listed in Table 7:
The SIM channels used by the two SIM mini-bursts which belong to the same SIM burst are separated in frequency to reduce fades and interference. There are 84 SIM channels that are paired in an order such that paired channels do not repeat (i.e. the pair {Mx, My} is only used once in the total possible paired set and the pair {My, Mx} is not be used).
The following tables are used to generate the SIM mini-burst channels from SIM burst channel index obtained by the algorithm given by
ch
1
=M
x+1
,ch
2
=M
x+43
where is the Mi is the ith SIM channel given in Table 5.
HIA burst protocol stack is shown in
REG mini-burst protocol stack is shown in
The Network Layer of the REG channel includes of the Message with the addition of the beacon 102 Identification Number. The resulting number of bits from the Network Layer are 64 bits, where MSB are transmitted first, as shown in
L0 burst protocol stack is shown in
The spectrum of the LOC Middle mini-burst is as shown in
The modulating signal in the ISM 3 LOC Lower mini-burst as shown in
LOC Lower mini-burst is shown in
The modulating signal in the LOC Upper mini-burst as shown in
A microprocessor may be used to generate the LOC Upper mini-burst as follows: The microprocessor outputs 8 binary samples of 0's followed by 8 binary samples of 1's, which corresponds to one period of the LOC Upper mini-burst (i.e. 1 period=16 binary samples). The entire LOC Upper mini-burst consists of 6912 periods (i.e. one LOC Upper mini-burst=6912×16 samples), with duration of 16.384 ms.
The data are partitioned to 72-bit (9-byte) blocks. If the length of data is not a multiple of 9 bytes, the beacon 102 adds some bytes of 0x00 to the end of the data. Each 9-byte block, i.e. 72 bits, are passed to the Data Link Layer for the SIM burst transmission. The Data Link Layer corresponding to the SIM burst utilizes Reed-Solomon coding as in the REG mini-burst, to implement enhanced forward error correction capability and reduce the undetected error rate which exists in the current system. The Data link layer for the SIM burst is illustrated in
A wireless communication system is described. A technical effect is bifurcated communications from multiple beacons. Although specific implementations have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement which is calculated to achieve the same purpose may be substituted for the specific implementations shown. This application is intended to cover any adaptations or variations. For example, although described in procedural terms, one of ordinary skill in the art will appreciate that implementations can be made in an object-oriented design environment or any other design environment that provides the required relationships.
In particular, one of skill in the art will readily appreciate that the names of the methods and apparatus are not intended to limit implementations. Furthermore, additional methods and apparatus can be added to the components, functions can be rearranged among the components, and new components to correspond to future enhancements and physical devices used in implementations can be introduced without departing from the scope of implementations. One of skill in the art will readily recognize that implementations are applicable to future communication devices, different file systems, and new data types.
