KR101281714B1 - Communication of transmitter identification using positioning pilot channels - Google Patents

Abstract

A method for communicating transmitter identification in an interlace structure of a communication network system using positioning pilot channels (PPCs), the method comprising:
a) encoding pilot information on a first portion of the plurality of subcarriers in a positioning pilot channel symbol for an active transmitter; And
b) encoding transmitter identification information on a second portion of the plurality of subcarriers of the symbol,
The first portion of the plurality of subcarriers comprises at least first and second interlaces, and the second portion of the plurality of subcarriers comprises at least a third interlace,
The pilot information is scrambled using a wide area identifier in the first interlace and scrambled using the wide area identifier and local area identifier in at least the second interlaces,
At least one of the interlaces includes the transmitter identification information in the form of one or more transmitter position coordinates in the pre-interlace.

Description

Transmission of transmitter identification using positioning pilot channels {COMMUNICATION OF TRANSMITTER IDENTIFICATION USING POSITIONING PILOT CHANNELS}

This patent application is filed with US Provisional Application No. 61 / 023,919, filed Jan. 28, 2008, US Provisional Application No. 61 / 024,143, filed Jan. 28, 2008, and US Provisional Application No. 61, filed February 20, 2008. / 030,178, which is assigned priority to the assignee of the present application, and is hereby expressly incorporated by reference.

The present invention relates generally to the operation of communication systems, and more particularly to methods and apparatus for transmitting identification information about a transmitter in a communication system.

Real-time and non real-time services in currently known communication systems, such as content delivery / media distribution systems (eg, forward link only (FLO) or digital video broadcast (DVB-T / H) systems). Are typically packetized into transmission frames (eg, FLO subframes) and delivered to devices on the network. Additionally, such communication systems may use orthogonal frequency division multiplexing (OFDM) to provide communications between a network server and one or more mobile devices. This communication provides a transmission superframe with data slots that are packetized with the content to be delivered over the distribution network as a transmission waveform.

It is known to achieve position determination and transmitter identification of mobile devices in some wireless networks through the use of Positioning Pilot Channels (PPCs) in FLO networks. In particular, known transmitter identification includes determining a channel profile from pilot symbols of an active PPC symbol from each individual transmitter to the receiver. Although the transmitter identity may not be explicitly encoded in PPC symbols, such as sequencing active transmitters in a pseudo time division multiple access (TDMA) scheme (e.g., the transmitters may only have one transmitter at a time). Following the known time sequence of active transmissions to be active in this given region), the identities of the transmitters in the given region can be determined as possible as a schedule known when the transmitters transmit active PPC symbols. Thus, with the further use of overhead channels (eg, overhead information symbols (OIS)) in the superframe, it is possible to use the position of the active PPC symbol in the superframe to map the transmitters to the corresponding PPC symbols. . Under this scheme, the periodicity (ie scheduling) of the network transmitters in terms of superframe can also be known by the receivers.

According to one aspect, a method for conveying transmitter identification in a communication system is disclosed. The method includes encoding pilot information on a first portion of a plurality of subcarriers in a positioning pilot channel symbol for an active transmitter; And encoding transmitter identification information on a second portion of the plurality of subcarriers of the symbol.

According to another aspect, an apparatus for conveying transmitter identification information in a network is disclosed. The apparatus includes a first module configured to encode pilot information on a first portion of a plurality of subcarriers in a positioning pilot channel symbol for an active transmitter; And a second module configured to encode transmitter identification information on a second portion of the plurality of subcarriers of the symbol.

According to another aspect, another apparatus for communicating transmitter identification information in a communication system is disclosed. The apparatus includes means for encoding pilot information on a first portion of a plurality of subcarriers in a positioning pilot channel symbol for an active transmitter; And means for encoding transmitter identification information on a second portion of the plurality of subcarriers of the symbol.

According to another aspect, a computer program product is disclosed. The computer program product includes code for causing a computer to encode pilot information on a first portion of a plurality of subcarriers in a positioning pilot channel symbol for an active transmitter; And a computer readable medium comprising code for causing a computer to encode transmitter identification information on a second portion of the plurality of subcarriers of the symbol.

In another aspect, at least one processor is disclosed that is configured to perform a method for transmitting transmitter identification information in a network. The method includes encoding pilot information on a first portion of a plurality of subcarriers in a positioning pilot channel symbol for an active transmitter; And encoding transmitter identification information on a second portion of the plurality of subcarriers of the symbol.

In another aspect, a method for transmitting transmitter identification information in an apparatus in a communication system is disclosed. The method includes receiving at least one symbol with a plurality of subcarriers from a transmitter. The method includes determining an energy measurement and a channel estimate of at least one symbol from a transmitter using a first portion of a plurality of subcarriers of the at least one symbol, and in at least one symbol to determine the transmitter identification information. Decoding the dedicated second portion of the plurality of subcarriers.

According to another aspect, an apparatus for transmitting transmitter identification information in an apparatus in a communication system is disclosed. The apparatus includes means for receiving at least one symbol having a plurality of subcarriers from a transmitter, and an energy measurement and channel estimate of at least one symbol from the transmitter using a first portion of the plurality of subcarriers of the at least one symbol. Means for determining the number. The apparatus further includes means for decoding a second dedicated portion of the plurality of subcarriers in at least one symbol to determine the transmitter identification information.

In yet a further aspect, a computer program product is disclosed. The computer program product includes code for causing a computer to receive at least one symbol having a plurality of subcarriers from the transmitter, and cause the computer to use a first portion of the plurality of subcarriers of the at least one symbol. Code for determining energy measurements and channel estimates of at least one symbol. The medium also includes code for causing a dedicated second portion of the plurality of subcarriers to be decoded in at least one symbol to determine the transmitter identification information.

In another further aspect, provided that transmitter identification information is signaled in the form of transmitter location coordinates (eg, GPS coordinates), new implementations for presenting and transmitting the transmitter identification information are provided herein.

1 illustrates a communication network that may utilize the disclosed transmitter identification scheme.
2 shows an example of a communication system characterized by transmission of transmitter identification information.
3 illustrates a transmission superframe that may be used in the systems of FIG. 1 or 2.
4 shows a functional diagram of the interlaced structure of an OFDM symbol used for PPC symbols transmitted by an active transmitter.
5 shows a functional diagram of the interlaced structure of an OFDM symbol used for PPC symbols transmitted by an active or inactive transmitter.
FIG. 6 illustrates an apparatus for encoding transmitter identification in an interlace of an active PPC symbol, such as shown in FIG. 4.
7 illustrates example hardware circuitry that may be used in a transmitter to generate an RM code.
8 shows a method for providing transmitter identification in a wireless system, such as systems as shown in FIGS. 1 and 2.
9 shows an apparatus for transmitting a PPC symbol with transmitter identification information.
10 illustrates a method for receiving a symbol that includes transmitter identification information.
11 shows a receiver device for use in a receiver available in a system with transmitter identification information, or alternatively, another example of the device.

The present disclosure relates to methods and apparatus for transmitting identification information about a transmitter in a communication system. The methods and apparatus provide a way for position determination and transmitter identification using PPC channels that do not require scheduling of transmitters in the local network area to be known to the receiver. In particular, the disclosed methods and apparatuses utilize PPC symbols that include transmitter identification information, so that the receiver only needs timing information from the superframe and PPC symbols to identify the identity of the active transmitter. In a particular example, the transmitter identity can be explicitly encoded in the PPC symbols. By explicitly encoding the transmitter identity in the PPC symbols, higher level scheduling information of network transmitters need not be known at the transmitter. However, in order to embed the transmitter identity into the PPC symbols in a robust manner, the transmitter must perform further processing, and the receiver must process the PPC symbols to extract the transmitter identity information. However, the transmitter identification information provides less processing resources that need to be used by the receiver to identify the transmitter, and provides a corresponding position location using the channel profiles of the identified transmitters. . In addition, additional information encoded with the identification may be signaled to the receivers, wherein the additional information relates to whether additional symbols are being used by particular transmitters.

For purposes of this description, a transmitter identification scheme is described with reference to a communication network that uses Orthogonal Frequency Division Multiplexing (OFDM) to provide communications between network transmitters and one or more mobile devices, such as FLO or DVB-T / H. Described in the specification. In one example, the disclosed communication systems can utilize the concept of a Single Frequency Network (SFN) in which signals from multiple transmitters in a network carry the same content and transmit the same waveforms. As a result, the waveforms can be observed as if they are signals from the same source with different propagation delays.

It is further noted that the example OFDM system disclosed herein may use superframes, for example. The superframes contain data symbols used to transmit services from a server to receiving devices. According to one example, a data slot may be defined as a set of a predetermined number of data symbols (eg, 500) occurring over one OFDM symbol time. In addition, the OFDM symbol time in the superframe may carry data of eight slots, as just one example.

According to a further example, a PPC in a superframe includes PPC symbols used to provide transmitter identification information about channel estimates for individual transmitters in the network to be determined. Individual channel estimates can be used for both network optimization (transmitter delay for network optimization and power profiling) and position positioning (through measurement of delays from all nearby transmitters according to triangulation methods).

In one example system, superframe boundaries at all transmitters may be synchronized with a common clock reference. For example, the common clock reference may be obtained from a global positioning system (GPS) time reference. The receiving device may use the PPC symbols to identify the channel estimate and the particular transmitter from the set of transmitters in the vicinity of the receiving device.

1 illustrates a communication network 100 in which the presently disclosed methods and apparatus may be used. The illustrated network 100 includes two wide areas 102 and 104. Each of the wide area regions 102 and 104 generally covers a wide geographic area, such as a state, a number of states, a portion of a state, an entire country, or more than one country. In turn, the wide area regions 102 and 104 may include local area regions (or sub-regions). For example, wide area 102 includes local area areas 106 and 108, and wide area 104 includes local area area 110. It is noted that the network 100 shows only one network configuration, and any number of wide area and local area regions may be considered.

Each of the local area regions 106, 108, 110 includes one or more transmitters that provide network coverage to mobile devices (eg, receivers). For example, region 108 includes transmitters 112, 114, and 116, which provide network communications to mobile devices 118 and 120. Similarly, region 106 includes transmitters 122, 124, and 126, which provide network communications to devices 128 and 130, and region 110 includes transmitters 132, 134, and 136. ), They provide network communications to devices 138 and 140.

As shown in FIG. 1, a receiving device may collect PPC symbols from transmitters in its local area, from transmitters in another local area within the same wide area, or from transmitters in a local area outside of its wide area. It may receive superframe transmissions that include. For example, device 118 may receive superframes from transmitters in its local area 108 as indicated by arrows 142 and 144. Device 118 may also receive a superframe from transmitters in other local areas 142 within wide area 102 as indicated by arrow 146. Potentially device 118 may further receive superframes from transmitters in local area 110 in another wide area 104, as indicated at 148.

Active transmitters, as disclosed in "Methods and Apparatus for Position Location in a Wireless Network" by Mukkavilli, et al., Filed Sep. 6, 2006, filed September 6, 2006, and are hereby expressly incorporated by reference. The PPC symbols transmitted are configured differently from transmitters that are idle or dormant at the same time for PPC symbol transmission. During operation, network positioning information is used by each transmitter to determine which transmitter in the area will be the “active transmitter”.

For purposes of this application, an active transmitter is a transmitter that transmits a PPC symbol containing identification information using at least some of the subcarriers (eg, interlace). The active transmitter is assigned only one active symbol, but it is possible for any number of active symbols to be assigned to the transmitter. Thus, each transmitter is associated with an "active symbol" and the transmitter transmits information including identification information with the active symbol. When the transmitter is not active, the transmitter transmits on a defined idle portion (eg interlace) of the PPC symbol. The receiving device in the network may then be configured to not "listen" the information in the idle portion of the PPC symbols. This enables the transmitters to provide power (ie energy per symbol) stability to maintain network performance during idle portions of PPC symbols. In a further example, the symbols transmitted on the PPC are designed to have a long cyclic prefix (CP) so that the receiving device can use the information from the far away transmitters for position determination purposes. . This mechanism allows the receiving device to receive identification information from a particular transmitter during its associated active symbol without interference from other transmitters in the region, which other transmitters transmit on the idle portion (interlace) of the symbol and Because there is.

2 illustrates an example of a communication system 200 that includes transmission of transmitter identification information (referred to herein as a TxID). System 200 may include a plurality of transmitters (eg, five transmitters) that transmit a superframe comprising a pilot positioning channel (PPC) 202 over a wireless link 204 to at least one receiving device 206. T1 to T5)). The transmitters T1-T5 represent transmitters in the vicinity of the device 206 and include transmitters in the same local area as the device 206, transmitters in different local areas, or transmitters in different wide areas. can do. Note that the transmitters T1 to T5 may be part of a communication network that is synchronized to a single time base (eg, GPS time) such that superframes transmitted from the transmitters T1 to T5 are synchronized in time and synchronized. do. It is noted that it is possible to allow a fixed offset of the start of a superframe over a single time and account for the offsets of the individual transmitters in the determination of the propagation delay. Thus, although the content of the transmitted superframe may be the same for transmitters in the same local area, it may be different for transmitters in different local or wide areas, which means that the network is synchronized and the superframes are aligned and the receiving device ( This is because 206 can receive symbols from nearby transmitters via PPC 202 and these symbols are also aligned.

As shown by example transmitter block 214, each of transmitters T1 through T5 may include transmitter logic 208, PPC generator logic 210, and network logic 212. As shown by example receiving device 222, receiving device 206 may include receiver logic 216, PPC decoder logic 218, and transmitter ID determination logic 220.

It is noted that the transmitter logic 208 may include hardware, software, firmware, or any suitable combination thereof. Transmitter logic 208 is operable to transmit audio, video, and network services using transmission superframes. The transmitter logic 208 is also operable to transmit one or more PPC symbols in a superframe. In one example, the transmitter logic 208 is used to provide transmitter identification information for use by the receiving device 222 to identify specific transmitters, as well as for other purposes such as positioning. Transmit one or more PPC symbols 234 within the superframe over.

The PPC generator logic 210 includes hardware, software or any combination thereof. The PPC generator logic 210 is operable to incorporate transmitter identification information into symbols 234 transmitted over the PPC 202. In one example, each PPC symbol includes a number of subcarriers grouped into a selected number of interlaces. In turn, an interlace can be defined as a set or collection of regularly spaced subcarriers spanning an available frequency band. It is also noted that the interlaces may consist of a group of subcarriers that are not regularly spaced apart.

In one example, each of the transmitters T1 to T5 is assigned at least one PPC symbol, referred to as an active symbol for that transmitter. For example, transmitter T1 is assigned a PPC symbol 236 in PPC symbols 234 in a superframe, and transmitter T5 is assigned a PPC symbol 238 in PPC symbols 234 in a superframe. do.

The PPC generator logic 210 is operable to encode transmitter identification information into an active symbol for that transmitter. For example, the interlaces of each symbol are grouped into two groups called "active interlaces" and "idle interlaces". The PPC generator logic 210 is operable to encode transmitter identification information on dedicated active interlaces of an active symbol for that transmitter. For example, transmitter T1 identification information is transmitted on active interlaces of symbol 236 and transmitter T5 identification information is transmitted on dedicated active interlaces of symbol 238. When the transmitter is not sending its identification on an active symbol, the PPC generator logic 210 is operable to encode idle information on idle interlaces of the remaining symbols. For example, if PPC 202 includes 10 symbols, up to 10 transmitters in the SFN network will each be assigned one PPC symbol as their respective active symbol. Each transmitter will encode identification information on active interlaces of its respective active symbol and encode idle information on idle interlaces of the remaining symbols. When the transmitter is transmitting idle information on idle interlaces of the PPC symbol, the transmitter logic 208 is operable to adjust the power of the transmitted symbol to maintain constant energy per symbol power level.

The network logic 212 may be configured by hardware, software, firmware, or any combination thereof. The network logic 212 is operable to receive network provisioning information 224 and system time 226 for use by the system. The provisioning information 224 is used to determine an active symbol for each of the transmitters T1 to T5 while each transmitter transmits identification information on the active interlaces of their active symbol. The system time 226 is used to synchronize the transmissions so that the receiving device can assist in propagation delay measurements as well as determine channel estimates for a particular transmitter.

The receiver logic 216 includes hardware, software, or a combination thereof. The receiver logic 216 is operable to receive PPC symbols 234 and transmit superframes on PPC 202 from nearby transmitters. The receiver logic 216 is operable to receive the PPC symbols 234 and pass them to the PPC decoder logic 218.

The PPC decoder logic 218 includes hardware, software, and combinations thereof. The PPC decoder logic 218 is operable to decode the PPC symbols to determine the identity of a particular transmitter associated with each symbol. For example, the decoder logic 218 is operable to decode the received active interlaces of that transmitter to determine the identity of a particular transmitter associated with each PPC symbol. Once the transmitter identity is determined, the PPC decoder logic 218 is operable to determine a channel estimate for that transmitter. For example, using the time reference associated with the received superframe, the PPC decoder logic 218 can determine the channel estimate for the active transmitter associated with each received PPC symbol. Thus, the PPC decoder logic 218 is operable to determine the number of transmitter identities and associated channel estimates. This information is passed to position determination logic 221.

The position determination logic 221 includes hardware, software, or a combination thereof. The position determination logic 221 is operable to calculate the position of the apparatus 206 based on decoded transmitter identification information and related channel estimates received from the PPC decoder logic 218. For example, the locations of transmitters T1 through T5 are known to network entities. The channel estimates are used to determine the distance of the devices from these locations. The position determination logic 221 uses triangulation techniques to triangulate the position of the device 206.

During operation, each of transmitters T1 through T5 encodes transmitter identification information on at least one of the active interlaces of an active PPC symbol associated with each transmitter. The PCC generator logic 210 is operable to determine which symbols are active symbols for a particular transmitter based on the network provisioning information 224. When the transmitter is not sending its identification information on the active interlaces of its active symbol, the PPC generator logic 210 causes the transmitter to send idle information on the idle interlaces of the remaining PPC symbols. Since each transmitter is transmitting energy in each PPC symbol (ie, either active or idle interlaces), the transmitter power does not experience fluctuations that disrupt network performance.

When device 206 receives PPC symbols 234 via PPC 202 from transmitters T1 through T5, the device 206 decodes transmitter identifiers from the active interlaces of each PPC symbol. Once a transmitter is identified from each PPC symbol, the device may determine a channel estimate for that transmitter based on available system timing. The apparatus continues to determine channel estimates for the identified transmitters until channel estimates (ie preferably four estimates) for multiple transmitters are obtained. Based on these estimates, the position determination logic 221 is operable to triangulate the position 228 of the device using standard triangulation techniques. In another example, the position determination logic 221 is operable to send the transmitter identifiers and associated channel estimates to another network entity that performs triangulation or other positioning algorithms to determine the position of the device.

In one example, the positioning system includes a computer program having one or more program instructions (“instructions”) stored on a computer-readable medium, wherein the computer-readable medium is executed when executed by at least one processor. It provides the functions of the positioning system described herein. For example, the instructions may be PPC generator logic 210 and / or PPC decoder logic from a computer-readable medium, such as a floppy disk, CDROM, memory card, flash memory device, RAM, ROM, or any other type of memory device. 218 can be loaded. In another example, the instructions can be downloaded from an external device or network resource. The instructions are operable to provide examples of the positioning system described herein when executed by at least one processor.

Thus, the positioning system is operable to determine at the transmitter that active PPC symbol that a particular transmitter will transmit its identification information on the active interlaces of the active PPC symbol. The positioning system is further operable to perform triangulation techniques to determine channel estimates and determine device position for transmitters identified in the received PPC symbols at a receiving device.

3 illustrates a transmission superframe 300 that may be used in the systems of FIG. 1 or 2. As shown, each superframe 300 includes time division multiplexed (TDM) pilots (eg, TDM1 and TDM2), a Wide Area Identification Channel (WIC), a Local Area Identification Channel (LIC), and Local. Prerequisite data 302 including an Area Identification Channel), and overhead information symbols (OIS), one or more data frames 304 (eg, four data frames in the example of FIG. 3), and a PPC / spare Symbols 306.

According to one example, the PPC symbols can be configured such that the cyclic prefix length is increased to half of the number of subcarriers, for example 2048 chips for 4096 subcarrier symbols. The increased cyclic prefix enables the receiving device to receive superframes, for example, to more properly characterize the variability of channel delay spreads. Thus, according to one example, each physical layer (PHY) PPC symbol will have a duration of 6161 chips (2048 chip cyclic prefix + 4096 chips + 17 chip window). It is noted here that this disclosed example assumes a " 4K " (ie 4096 chip window) fast Fourier transform (FFT) mode. Additionally, according to one example, as will be discussed below, one PHY PPC symbol (ie, a "4K" FFT) has a duration of 6161 chips with eight interlaces per symbol, as the media access control (MAC) PPC symbol PHY for PHY). However, the PPC symbol structure may be configured to be similar to the data symbol structure for the corresponding FFT mode (eg, 1K, 2K, or 8K). Thus, for the 1K or 2K FFT mode, again assuming that the cyclic prefix is equal to half of the FFT window and 17 windowing chips, the number of chips per symbol is, for example, 1553 chips (1024 chips + 512 cyclic chips each). Prefix + 17 windowwing chips) and 3089 chips. The number of MAC PPC symbols (eg, 8) in the superframe will still be the same as in the 4K mode. It is noted that this numerology is merely an illustrative example and that those skilled in the art will understand other PPC symbol configurations and durations within the scope of the present disclosure.

As can be collected from the discussion above, the cyclic prefix for PPC symbols in all FFT modes will be different from the data symbols. For example, rather than the typical 512 chips for data symbols, the cyclic prefix for the 4K FFT mode is 2048 chips as described above.

4 shows a functional diagram of the interlace structure of OFDM symbol 400 used for PPC symbols transmitted by an active transmitter. According to the example numerology based above discussed, symbol 400 will include 4096 subcarriers divided into 8 interlaces I ₀ -I ₇ and grouped, as shown, respectively. The interlace of s typically contains 512 subcarriers that are not adjacent frequencies or tones. As mentioned previously, the receiver needs to be used. First, the receiving device needs to determine the channel estimate using the pilot subcarriers in the symbol. Secondly, the receiving device needs to determine the identity of the transmitter corresponding to the channel estimate.

Interlaces in active symbol 400 are used to transmit pilot tones as well as transmitter identification information. In the particular example of FIG. 4, not only the first portion of the subcarriers of symbol 400, interlace I ₁ , which is classified as 410, ie interlaces I, which are classified by reference numerals 402, 404, 406 and 408, respectively. ₀ , I ₂ , I ₄ , I ₆ ) are the active interlaces used to transmit pilot tones. In the case of interlaces I ₀ , I ₂ , I ₄ , I ₆ , the pilots have a wide scrambler seed (ie, wide discriminator bits (WID)) to ensure maximum interference suppression across the network (s). And the local region scrambler seed (ie, local region discriminator bits (LID)). In addition, to transmit pilots that are scrambled only with the WID (e.g., LID is set to 0) to reduce the number of hypothesis and thus processing required by the receiver and thus to jointly determine the WID and LID, The interlace I ₁ is used by an active transmitter.

According to a specific example, the wide area identifier WOI ID and the local area identifier LOI ID are available at higher layers and in fact are available when OIS symbols are decoded. In the physical layer, transmissions across various regions and sub-regions (ie, wide areas and local regions) are distinguished through the use of different scrambler seeds (WID and / or LID). For example, WID may be a 4-bit field and may separate wide area transmissions, and LID may be another 4-bit field and may separate local area transmissions. Since there are only 16 possible WID values and 16 possible LID values, the WID and LID values may not be unique across the entire network deployment. For example, a given combination of WID and LID can potentially map to multiple WOI IDs and LOI IDs. Nevertheless, network planning can be accomplished such that re-use of WID and LID is geographically separated. Therefore, in a given environment, it is possible to map a given WID and LID to a particular WOI and LOI without any ambiguity. Therefore, at a given physical layer, the PPC waveform is designed to carry WID and LID information (ie, scrambling to interlaces I ₀ , I ₂ , I ₄ , I ₆ and I ₁ ).

As noted above, an active transmitter must transmit at least 2048 pilots to enable the receiver to estimate channels with the necessary delay spreads. This corresponds to four interlaces for the active transmitter. Four interlaces (eg, I ₀ , I ₂ , I ₄ , I ₆ ) are scrambled using the WID and LID for the wide and local area to which the transmitter belongs. The receiver of the symbol will therefore first extract WID and LID information from the pilots in the active interlaces of the PPC symbol, and then use the WID / LID information to obtain a channel estimate from that particular transmitter. Scrambling with WID and LID also provides interference suppression from transmitters in neighboring local area networks.

However, the corresponding WID / LID identification step at the receiver can be complicated. For example, if each interlace is scrambled using both WID and LID, the receiver will have to jointly detect the WID and LID seeds used for scrambling. There are 16 possibilities each, so that the receiver must try 256 hypotheses for joint detection. Thus, receiver detection can be simplified by enabling separate detection of WID and LID seeds. Therefore, in the disclosed example, the PPC waveform is composed of subcarriers or interlaces (eg, interlace I ₁ , identified by reference numeral 410) with pilots scrambled using only WID values with the LID bit set to 0000. Include other groups.

In addition to the above, the apparatus and methods include the use of other portions of subcarriers to transmit specific transmitter identification information that is self-contained in PPC symbol 400. In particular, this second portion of the subcarriers includes another nonzero interlace in the PPC symbol. According to the example shown in FIG. 4, interlace I ₃ , classified at 412, may include the transmitter identification information, although any other free interlace may have been used. This complete transmitter identification allows the receiver to process the PPC independently of normal frame processing. In particular, the acquisition of transmitter identification can only be derived from PPC processing and will only depend on the detection of the TDM1 pilot channel, which is used for coarse timing detection for PPC processing. In addition, this results in a transmitter specific PPC channel that can be useful for supporting location specific applications in a communication network, since each transmitter is essentially provided with an interference free channel. Thus, for example, each transmitter may be configured to impart information regarding a particular application, with only transmitter specific identification information over the transmitter specific channel being a matter of concern. Thus, interlaces in additional PPC symbols can be used to convey specific application data to the receiving device.

The particular type of information included in the transmitter identification information may include first transmitter identifier bits, which provide a unique identifier for the transmitter. In one example, the number of bits considered may be 18, but any suitable number of bits may be used. In addition, additional signaling information bits may be assigned to the transmitter identification information to indicate with greater specificity about the additional information to be transmitted. For example, the signaling information can be used to indicate to the receiving device whether the transmitter uses additional symbols for transmitting other information and how many additional symbols will be used. In one example, the signaling information consists of 3 bits. Thus, in this example, the payload of the transmitter identification information will be 21 bits (18 bits for the transmitter ID + 3 bits for the signaling information), but fewer or more numbers may be considered.

The transmitter identification information may also include an error detection code, such as a cyclic redundancy check (CRC). In one example, the CRC function can be defined as CRC polynomial g (x) = x ⁷ + x ⁶ + x ⁴ + 1, which yields a 7 bit CRC.

Interlace I ₃ , classified as 412 (although any other pre-interlace may be used) may store transmitter identification information in the form of one or more transmitter location coordinates (eg, GPS longitude, latitude and / or altitude coordinates). It may include. In addition, slot 3, as a possible transmitter identification indication store, may also contain network delay information. The interlaces, when used with transmitter location identification, are also referred to herein as slots. As a result, in one aspect, slot 3, i.e. interlace I ₃ , may maintain transmitter TX location information.

In Approach 1, one approach, a fixed bit PPC packet length of, for example, 80 bits is used regardless of whether transmitter identification or other parameters are signaled within the PPC packet. This gives 10 blocks of 8 bits, each of which is converted into 100 bits. Longer payloads can be achieved when compared to shorter length PPC packets. A single PPC packet size is useful for both testing and implementation. The packet type (field allocation) is complete and enables scalability to include other parameters such as transmitter power and super-frame number. Two ways of implementing how the PPC bits are allocated are shown with options 1 and 2 shown on slide 1. Read-Muller encoding can be used with both implementations. Other variations include using the same base 64,7 lead-muller code but reducing it to (41,7). Instead of reserving 50 bits, the transmitter ID is repeated twice in option 2. Other coding schemes are possible in generating 68 bits from an 18 bit transmitter ID.

In another approach, approach 2, a 56 bit PPC packet is used, regardless of whether transmitter ID information is signaled within the PPC packet. One bit allocation is illustrated on slide two. Further attributes and benefits of Approach 2 are shown in slides 3 and 4.

A third approach, approach 3, is described on accompanying slides 5-8 with sample format assignment shown on slide 17. FIG. For each PPC MAC time unit, each transmitter may be in one of three states: inactive, identified or reserved, and using Approach 3, the reserved state of the PPC is used as a transmitter-specific channel. The information includes the transmitter ID information as well as the longitude, latitude, and altitude of the transmitter in addition to the network delay. This approach allows larger payloads to use turbo encoding. Turbo encoding provides a more robust encoding compared to Read-Muller encoding for 1000 bit payloads as shown on slide 6. As shown on slide 5, one embodiment includes four pilot slots with three data slots. The PPC transmitter ID information and the PPC transmitter location information may be located in arbitrary data slots. Another embodiment includes five data and two pilot slots. There are more duplications using 5 data slots compared to using 3 data slots. As can be further seen in FIG. 4, two interlaces or groups of subcarriers (eg, interlaces I ₅ and I ₇ in the example of FIG. 4) are idle or removed from the active PPC symbol 400. The energy of each interlace is (8/6) times the total OFDM symbol energy to ensure essentially constant power levels for each OFDM PPC symbol, but at active symbol 400 It is noted that the power or energy allocation between the interlaces used (eg, interlaces I ₀ -I ₄ and I ₆ ) need not be constant, rather the energy can be distributed differently between the different interlaces. For example, the energy for interlace I ₃ can be set to 8E / 3, while the energy of interlaces I ₀ , I ₂ , I ₄ and I ₆ together with the energy of interlace I ₁ is 2E /. Can be set to 3 , That is the energy level of interlace (I ₃₎ is four times greater than the energy of each of the five interlaces _{(I 0, I 1, I} 2, I 4 and I _6).

Given the exemplary superframe structure as described above, a superframe can support eight transmitters in the local area using eight PPC symbols available per superframe. However, the number of transmitters in the local area may be greater than eight in certain deployments. In addition, only transmitters in a particular local area are limited to being orthogonal in time. Therefore, network planning may be used to schedule transmitters across different local areas such that magnetic interference in the network is prevented or at least mitigated.

In addition, it may be desirable to support more than eight transmitters per local area. For example purposes, assume 24 transmitters are supported in the local area. To support this deployment, the network may be configured such that each transmitter sends an active PPC symbol once every three superframes. In this case, network planning and overhead parameters may be used to inform the transmitters when an active state of each of the transmitters occurs and when the transmitters transmit identification information on the assigned active symbol. Thus, the periodicity of the three superframes is programmable at the network level so that the system is scalable enough to support additional transmitters. The periodicity used by the network can be kept constant during network deployment so that both network information as well as the overhead information used to convey the information can be simplified. In one example, information about periodicity used in the network is broadcast as overhead information at higher layers to enable easier programming capability of this parameter. In addition, with the 30 PPC symbols available for each local area, the constraints on network planning to mitigate interference at the boundary of two different local areas are also relaxed.

FIG. 5 shows an example PPC symbol transmitted by passive or inactive transmitters in the network, such as shown in FIGS. 1 and 2. As can be seen, the inactive PPC symbol 500 has interlaces I _0- I ₆ removed. Interlace I ₇ , referred to as number 502, is the only interlace in passive transmitter symbol 500 with nonzero energy. Pilots transmitted in interlace I ₇ do not contain important data or information, and the interlace may be referred to as a “dummy” interlace. According to one example disclosed, in order to meet certain OFDM symbol energy constraints, the energy in interlace I ₇ is also scaled to eight times the available energy per OFDM symbol interlace. The transmission of the passive or inactive PPC symbol 500 ensures that the transmission therein does not interfere with the pilots of the active transmitters, which are interlaces I ₀ , I ₁ , I ₂ , I as shown in FIG. 4. ₄ and I ₆ ).

FIG. 6 shows an apparatus 600 for encoding transmitter identification in an interlace of an active PPC symbol, such as shown in FIG. 4. The apparatus 600 first includes a module 602 for setting or determining transmitter identifier (TxID) bits and allocation bits. As mentioned above, the number of bits for TxID and allocation may be set to 18 and 3, respectively. Assuming this implementation for purposes of explanation, 21 bits are passed from module 602 to module 604, which module 604 assigns the CRC bits to the assigned bits and the TxID (eg, 7 bits as described above). Is added). Module 604 then passes the entire bits (collectively referred to as “transmitter identification information”) to interleaver 606 (eg, block interleaver). Assuming 28 bits are passed, the block interleaver 606 may be configured as a 4 x 7 matrix in which bits are written in the column-direction and correspondingly read in the row-direction to achieve interleaving. However, it is noted that various other types of suitable interleaving may be considered by those skilled in the art for use with the presently disclosed apparatus and methods.

The interleaved bits are read into encoder 608 to encode the bits according to a predetermined encoding scheme. In one example, encoder 608 may use a read-muller (RM) error correction code, such as a primary (64, 7) RM code, to encode the bits. In such an example, the interleaver 606 passes 28 information bits to the encoder 608. Using a (64,7) RM code, four code blocks of 64 bits would result from encoding 28 information bits. However, in one particular example where 250 coded bits are suitable for a particular numerology, the resulting 256 bits will be too large. Thus, two bits of the (64,7) RM code can be punctured, resulting in a (62,7) RM code as described by the puncture module 610 in the encoder 608. . In one particular example, the bits corresponding to positions 62 and 63 of the Read Muller codeword can be punctured. Thus, when 28 information bits are encoded, the result will be 248 encoded bits. As further described by the zero insertion module 612 in the encoder 608, two zeros may be added to the four code blocks to achieve 250 coded bits. The receiver will, in turn, assume that the bits are zero during decoding.

7 illustrates an example hardware circuit 700 that may be used at a transmitter, more specifically within encoder 608, to generate an RM code. As shown, the hardware circuit 700 receives a seven bit input, illustrated as inputs 702 that receive input bits m ₀ through m ₆ . The circuit 700 also includes a k-1 (eg, 6) bit counter 704, which receives a clock input that increments the counter 704. The output of the counter 704 is multiplied by each of the input bits m ₀ to m ₅ by separate multipliers 706. Additionally, the most significant bit m ₆ is multiplied by a constant binary " 1 " value (block 708). The outputs of the multipliers are summed by summing block 710 to output an RM (64,7) codeword that is a series of 64-bit values c ₆₃ to c ₀ . In one example, it is noted that a punctured code can be achieved by dropping values c ₆₂ and c ₆₃ .

Returning to FIG. 6, once transmitter information is encoded by encoder 608, a repeater 614 may be used to ensure that the number of bits is suitable for the particular numerology of the communication system. Such repetition provides an increase in processing gain at the receiver. From the example above, the 250 bits output by encoder 608 may be repeated four times for a total of 1000 bits, which would lead to a 6 dB processing gain at the receiver. After repeater 614 repeats the bits, the bits are scrambled as described by scrambler 616. In one example, the bits can be scrambled using the same slot mask as the interlace index, and a seed based on a PPC symbol index (eg, 0-7 in this example). After scrambling, modulator 618 modulates the scrambled bits for transmission in accordance with any of a variety of modulation schemes. In the above example using 1000 bits, the bits can be mapped to QPSK symbols, which leads to 500 QPSK symbols. In an OFDM physical layer symbol with 4096 data subcarriers each divided into eight interlaces of 512 bits, 500 QPSK symbols will fill one interlace, which is a PHY layer symbol into PPC symbols with 6457 chip duration. Depending on their matching, they may span one or multiple physical layer symbols. It is noted that the use of repeater 614, scrambler 616, and modulator 618 is just one example of a modulation scheme and one of ordinary skill in the art would appreciate that other suitable modulation schemes may be used with the disclosed methods and apparatuses.

In addition, in the above example, it is assumed that the mode of the receiver has a 4096 samples (ie, "4K") fast Fourier transform (FFT) window. It is noted that other FFT modes (eg, 1K, 2K, or 8K) are considered using the same methods and apparatus.

After modulation by modulator 618, the modulation symbols may be interleaved by interleaver 620 to mitigate frequency changes that may occur, such as during transmission on a transmission channel. Additionally, depending on the FFT mode, the interleaved modulation symbols are mapped to one or more PPC physical layer (PHY) symbols. In the example above of the 4K FFT mode, 500 modulated symbols are interleaved and mapped to one PHY PPC symbol. In another example of 2K FFT mode, the interleaved symbols may be interleaved or more, and interleaved between different interlaces (in interlace).

8 illustrates a method 800 for providing transmitter identification in a wireless system, such as the systems illustrated in FIGS. 1 and 2. For example, the method 800 is suitable for use by the transmitter in the network to allow the receiving device to identify the transmitter as well as determine positioning based on transmitter identification. In one example, the method 800 may be accomplished by a transmitter configured as described at 214 shown in FIG.

As shown, after initiation of the method 800, the flow proceeds to block 802 where transmitter identification information is determined. As one example, such information may be obtained from network positioning data 224 sent to transmitter 214 as shown in FIG. Alternatively, the transmitter identification (TxID) information may be unique to the transmitter based on defined network planning.

After the TxID information is determined or retrieved, information about whether the transmitter is active or idle for the purposes of PPC symbols is received by the transmitter as described by block 804. As previously described, active transmitters transmit on active interlaces of a particular current PPC symbol, whereas current idle transmitters transmit on idle or dummy interlaces of a current PPC symbol. In one example, network logic (eg, logic 212) at a transmitter (eg, transmitter 214 of FIG. 1) provides an indication of the current transmitter status from network provisioning data 224 from an appropriate network operating entity or device. Receive.

At decision block 806, a determination is made as to whether the transmitter for the current PPC symbol is active or idle mode. This determination may be accomplished by the PPC generator logic 210 at the transmitter 214 shown in FIG. 2 as an example.

If the transmitter is active for the current PPC symbol, pilots are encoded on the first portion of subcarriers by scrambling pilots using WID and LID seeds (eg, interlaces I ₀ , I ₂ , I ₄ and I ₆ ). The flow proceeds to block 808. Additional pilots are encoded on an additional portion of the first portion of subcarriers by scrambling pilots using only the WID seed (eg, subcarriers of interlace I ₁ ) as shown at block 810. The designated “first portion” of the subcarriers is used to convey pilot tones such as subcarriers of interlace I ₁ as well as subcarriers of interlaces I ₀ , I ₂ , I ₄ and I ₆ . It is noted that it implies some of the many available subcarriers. Encoding of pilots as shown by blocks 808 and 810 may be accomplished by transmitter logic 208 and PPC generator logic 210 shown in FIG. 2 as an example.

A second portion of the subcarriers (eg, subcarriers of interlace I ₃ ) are encoded with transmitter identification (TxID) information as described by block 812. As previously described with respect to the examples of FIGS. 4, 6, and 7, encoding of TxID information is accomplished according to a predetermined encoding scheme. Encoding of the TxID as shown by block 812 may be accomplished by the transmitter logic 208 and the PPC generator logic 210 shown in FIG. 2 as an example.

After the TxID is encoded, the PPC symbol is sent as described by block 814. Then, block 804 may proceed again for encoding of the next PPC symbol in either the same superframe or a subsequent superframe. Transmission of the symbol may be accomplished by transmitter logic such as logic 208 as an example.

If the current PPC symbol is not the active symbol when determined at decision block 806, flow proceeds to block 816 alternatively as shown in FIG. In this case, the available subcarriers of the defined group of multiple available subcarriers of the current PPC symbol (eg, interlace I ₇ ) are encoded along with the idle information as shown by block 816. Such encoding may be accomplished by PPC generator logic 210 and transmitter logic 208 as an example. After encoding at block 816, flow proceeds to block 814 for transmission of the PPC symbol.

It is further noted that the power level of the PPC symbol may also be performed as part of the transmission of the PPC symbol at block 814. This ensures constant symbol power for the SFN system as discussed previously. Power regulation may be accomplished by the transmitter logic 208 as an example.

The method 800 is thus operable to provide a system for providing transmitter identification via PPC symbols from a transmitter. It is noted that the method 800 represents just one implementation and that changes, additions, deletions, combinations or other modifications of the method 800 are possible within the scope of the present disclosure. For the purpose of simplifying the description, the method of FIG. 8 is shown and described as a series or multiple operations, but the processes described herein are not limited to the order of operations and some operations may occur in a different order and / or as described herein. It should be understood that they may occur concurrently with other operations other than those shown and described in the specification. For example, those skilled in the art will recognize that a methodology may alternatively be represented as a series of interrelated states or events, such as a state diagram. Moreover, not all illustrated acts may be required to implement a methodology in accordance with the disclosed exemplary method.

9 shows an apparatus for transmitting a PPC symbol with transmitter identification information. The apparatus 900 may be implemented as a transmitter, such as transmitter 214 of FIG. 2, or as a component of the transmitter. The apparatus 900 includes a module 902 configured to receive network provisioning data (eg, transmission status information). The module 902 may include data such as provisioning data 224 shown in FIG. 2, information about whether the transmitter is active or idle for PPC transmission, or information about the status of the transmitter, such as transmitter identification information (TxID). Any other suitable data that it passes can be received. As one example of an implementation of module 902, one or more transmitter logic 208, PPC generator logic 210, and network logic 212 may be used.

The apparatus 900 further includes a module 904 for encoding pilot information on the first portion of the plurality of subcarriers in the symbol for the active transmitter using the seed WID. As an example of the implemented functionality of this module, the first portion of the plurality of subcarriers may be subcarriers grouped into interlace I ₁ and scrambled using a WID seed (eg, LID set to 0000). . Another module 906 for encoding transmitter identification information on an additional portion of the first portion of the plurality of subcarriers of the symbol using WID and LID seeds is shown in FIG. 9. In a particular example, module 906 may be configured to encode pilot information using subcarriers in interlaces I ₀ , I ₂ , I ₄ , and I ₆ .

Although modules 904 and 906 are shown as being bifurcated in the example of FIG. 9, these modules may include multiple subcarriers; That is, it may be configured as a single module for encoding pilot information on subcarriers belonging to the first portion of the interlaces I ₀ , I ₁ , I ₂ , I ₄ , and I ₆ . It is noted that one or more transmitter logic 208, PPC generator logic 210, and network logic 212 may be used as an example of an implementation of modules 904 and 906.

Apparatus 900 further includes a module used to encode transmitter identification (TxID) information on a second portion of a plurality of subcarriers (eg, subcarriers of interlace I ₃ ) according to a predetermined encoding scheme. 908). It is noted that one or more transmitter logic 208, PPC generator logic 210, and network logic 212 may be used as an example of an implementation of modules 904 and 906.

The apparatus 900 also includes a module 910 that is configured to transmit a PPC symbol, where the PPC symbol includes a TxID on the second portion and encoded pilots on the first portion of the plurality of subcarriers. Implementation of module 910 may be with transmitter logic 208 or PPC generator logic 210, or a combination thereof.

At least one of the modules 902, 904, 906, 908, 910, and 912 configured to execute program instructions or code to provide aspects of a system that includes transmitter identification and positioning as described herein It is noted that it may be implemented by a processor of. Additionally, memory device 914 or equivalent computer-readable medium may be provided in connection with at least one process for storing the program instructions or code.

10 shows a method 1000 for receiving a symbol that includes transmitter identification information. For example, the method 1000 is suitable for use by a receiving device in a network to receive and decode PPC symbols transmitted by a currently active transmitter, such as transmitter identification and position determination. In one example, the method 1000 may be accomplished by a receiver configured as described at 222 as shown in FIG. 2. In addition, the method 1000 is used.

As shown, flow proceeds to block 1002 once the method is initiated for a received symbol. At block 1002, at least one PPC symbol is received by the receiver. In a particular example of a receiver in 4K mode, receiving at least one PPC symbol involves collecting 4096 samples of the input signal. As shown, block 1002 can be used to determine one or more interlaces, such as to set scale factors of the FFT as well as to determine threshold energy values for determining WID and LID values, as discussed below. It may also include measuring energy. In a particular example, the energy of interlace I ₁ may be measured from time domain interlace samples of the first received PPC PHY symbol. In addition, the energy of unused interlace (eg interlace I ₃ ) can also be measured to determine a measure of total interference on the PPC channel (eg, thermal and / or induced signal). In another example, in order to program the thresholds and FFT scale factors to be used by the hardware, the hardware of the receiver, such as receiver 222, may be configured to interrupt the processor, such as a digital signal processor (DPS). . Setting the FFT scale factors as an example allows to improve the quantization noise floor for signals from weak transmitters.

The flow then proceeds to block 1004, where a group of subcarriers including pilots scrambled using only the WID; That is, as previously discussed, the WID is determined from interlace I ₁ . In one example, this determination may be accomplished by receiver logic 216 and PPC decoder logic as shown in FIG. In a further example of the 4K mode, it is noted that a 512 point (pt) FFT can be used, which yields frequency domain samples. In an example system, WID detection is a repeated sequence that descrambles an inverse FFT to produce time domain samples (it is repeated 16 times in one example system using 16 WID seeds), which compares the samples to an energy threshold. (Based on the energy measurement of the interlace), and accumulating energy values of samples above the threshold to determine which hypothesized WID value yields the maximum energy. The WID maximum energy will correspond to the WID value.

After the determination of the WID value, the LID value is then determined as shown by block 1006. Specifically, the LID may include a group of subcarriers including WID and pilots scrambled using the LID; That is, it is determined from the interlace I ₀ . In one example, this determination may be accomplished by receiver logic 216 and PPC decoder logic as shown in FIG. In a further example of the 4K mode, it is noted that a 512 point FFT can be used to yield frequency domain samples. In an example system, the LID detection will include a repeated sequence of descrambling using the WID detected from block 1002 (it is repeated 16 times in one example system using 16 WIDs and 16 LID seeds), Perform an inverse FFT to yield time domain samples, and compare these samples with an energy threshold to determine which hypothesized LID value yields the maximum energy (based on the energy measurement of the interlace, such as interlace I ₁ ). So). The LID maximum energy will correspond to the LID value.

At block 1008, a number of subcarriers encoded with pilots are used to determine the channel estimate. In particular, interlaces I ₀ , I ₂ , I ₄ , and I ₆ may be used to obtain a channel estimate. In one example of a receiver in 4K mode, 512 sample FFTs are performed in each of the four interlaces to obtain frequency domain samples. The samples are then descrambled using previously obtained WID and LID seeds. Descrambled pilots in the frequency domain may be input to 2048 (2K) sample IFFTs to obtain a time domain channel estimate. Once the time domain channel estimate is determined, the energy for each tap to be read by a processor, such as a DSP, is calculated and stored. In addition, the calculated energy may be compared to a threshold based on previously measured energy of an unused interlace (eg, interlace I ₅ ) to determine the signal power of the currently active transmitter. It is noted that the procedure of block 1008 may be accomplished by receiver logic 216 and PPC decoder logic as shown in FIG. 2 as examples.

In another example of a procedure for determining a channel estimate assuming the above example, it is noted that the 2K time domain channel estimate may be aliased back to 512 time domain points or samples. An example of an aliasing pattern is given by the following relationship:

(1)

(One)

는 시간 도메인 채널 추정치고, s는 데이터 인터레이스이며, q는 채널 빈 인덱스이고, 여기서 채널 빈은 이 특정한 예에서 512개의 채널 탭들을 포함한다. 따라서, 관심 데이터 인터레이스(s)가 3이면, 일 예로서, 상기 등식 (1)은 다음이 된다:here,

Is a time domain channel estimate, s is a data interlace, q is a channel bin index, where the channel bin contains 512 channel taps in this particular example. Thus, if the data of interest interlace s is 3, as an example, equation (1) becomes:

(2)

(2)

가 등식 (2)에 주어진 바와 같이 결정된 이후에, 다음에 의해 주어진 바와 같이 위상 램프가 시간 도메인 추정에 적용될 수 있다:Channel estimate

After is determined as given in equation (2), a phase ramp can be applied to the time domain estimation as given by:

(3)

(3)

상에서 수행될 수 있다. For the purpose of decoding the interlace, the dedicated data interlace contains transmitter identification information, and the above example assumes the interlace I ₃ given in the example of FIG. 4, which includes interlace s = 3 or, in other words, the TxID. do. 512 sample FFT uses frequency domain samples to obtain channel estimate

It can be performed in the.

After block 1008, flow proceeds to block 1010 where the dedicated data interlace with transmitter identification information (TxID) is decoded. As shown in FIG. 4, this dedicated interlace may be interlace I ₃ . As one specific example of a process for decoding at a receiver in the 4K FFT mode, a 512 sample FFT as described above may be performed on the aliased dedicated data interlace I ₃ to generate frequency domain samples. The process of block 1008 may include using the corresponding channel estimates to generate 1000 bit log likelihood ratios (LLRs) for interlace I ₃ with QPSK modulation. The LLRs can then be de-interleaved similar to the de-interleaving of data symbols. As a result, 1000 bit LLRs can be averaged over four periods to reach 250 bit LLRs. Such averaging can be achieved, for example, according to the following relationship:

(4)

(4)

는 k번째(k^th) 값에 대한 평균 LLR을 나타낸다. 상기 LLR들이 250 비트 LLR들을 산출하도록 평균된 이후에, 그들은 DSP와 같은 프로세서에 의해서 프로세싱될 수 있다. 일 예에서 상기 평균화가 예컨대 수신기 로직(216) 및/또는 PPC 디코더 로직(218)에 의해 구현되는 하드웨어에 의해서 수행될 수 있음이 주목된다. 추가적으로, 상기 프로세서는 도 2에 도시된 예시된 수신기 로직(216) 및/또는 PPC 디코더 로직(218)에 의해 포함될 수 있고, 이는 반드시 단지 하드웨어 로직 장치들만을 포함하는 것을 의미하지는 않는다. here,

^Represents the mean LLR for the k ^th value. After the LLRs are averaged to yield 250 bit LLRs, they can be processed by a processor such as a DSP. It is noted that in one example the averaging may be performed by hardware implemented by, for example, the receiver logic 216 and / or the PPC decoder logic 218. In addition, the processor may be included by the illustrated receiver logic 216 and / or PPC decoder logic 218 shown in FIG. 2, which does not necessarily include only hardware logic devices.

After the 250 bit LLRs are passed to the processor, Read Muller decoding may be performed. For example, assuming the exemplary encoding discussed before using RM (64,7) coding, a 64-dimensional fast Hadamard transform (FHT) of the LLRs is calculated for each codeblock. In addition, since only 62 bits of the 64 bits containing the (64,7) RM code are transmitted by puncturing in the example encoding discussed, the receiver is a punctured bit for decoding purposes. Can be replaced with zeros. Thus, transform F is equal to HXL, where H is a 64 X 64 Hadamard matrix, and L represents LLRs corresponding to an RM code block (ie, the above-described example using four code blocks for 28 bits). 7 bits assuming coding). After the transform F is completed, the position of the largest sized entry in the transform F is determined. Due to the nature of the FFT, a binary representation of the location of the full size entry will provide six of the seven message bits in the RM code block. The sign of the maximum size entry provides the seventh message bit, where the message bit is zero if the sign is positive and one if it is negative.

If all the RM code blocks containing the transmitter identification information are decoded (i.e. four RM code blocks in this example), a cyclic redundancy check (CRC) is performed to ensure a high probability that the received message bits are error free. Can be checked. If a CRC is matched, the transmitter identification information as well as the WID, LID, and power measurement values are not available by the receiver.

Transmitter data in the transmitter identification information may be used by the receiving device to identify a transmitter that issues an active PPC symbol as indicated by block 1012. Since the PPC symbol includes complete transmitter identification information, the receiving device does not need to perform further processing to identify the transmitter, thus providing fast and efficient transmitter identification. Additionally, in order to determine positioning information for the receiving device with respect to transmitter (s), such as through triangulation or any other suitable technique, along with one or more channel estimates, WID, LID, and power measurement information, It is noted that information can be used.

After the process of block 1012, the flow proceeds to decision block 1014. It is determined whether additional or other PPC symbols are indicated from the signaling information in the transmitter identification information. If no additional symbols are displayed, process 1000 ends. Alternatively, if additional symbols are indicated, flow proceeds from block 1014 to block 1016 for further decoding of additional symbols. It is noted that the processing can be performed in a manner similar to the processes discussed above in connection with one or more of blocks 1002-1008.

It is noted that processes for decoding symbols for other FFT modes at the receiver apparatus are also considered. For example, assuming a 2K FFT mode, the receiving device collects 2K samples from each symbol. A 256 point FFT may be performed for each time domain interlaced sample of a symbol. The frequency domain interlaced symbols from a 256 point FFT may be concatenated with samples across two symbols (eg, PHY symbols). As an example, the set of 256 interlaced samples from the first symbol is represented as Y ₀ = {y _0,0 , y _1,0 , y _2,0 , ..., y _255,0 }, and the second symbol If the set of 256 interlaced samples from is expressed as Y ₁ = {y _0,1 , y _1,1 , y _2,1 , ..., y _255,1 }, the resulting concatenation of these two samples sets Y = (y _0,0 , y _1,0 , y _2,0 , ..., y _255,0 , ... y _0,1 , y _1,1 , y _2,1 , ..., y _255,1 }. After concatenation of 512 samples from multiple PHY symbols, WID and LID detection, channel estimation and LLR generation are processed in a 4K FFT mode of operation, as discussed above in connection with one or more of blocks 1002-1016. May be similar to

In another example of the 1K FFT mode, a 128 point FFT on time domain interlace samples from each PHY PPC symbol. Similar to the example above, the resulting frequency domain samples from four PHY PPC symbols are concatenated to form one interlace. In another example of the 8K FFT mode, it is noted that one interlace consists of 1000 subcarriers. Thus, processing by the receiving device will use 4K IFFT processing as well as 1K FFT / IFFT for channel estimation.

The method 1000 thus operates to provide for receiving and processing a symbol comprising transmitter identification information at a receiving device. It is noted that the method 1000 is just one implementation and that changes, additions, deletions, combinations or other modifications of the method 1000 are possible within the scope of the present disclosure. For the purpose of simplifying the description, the method of FIG. 10 is shown and described as a series or multiple operations, but the processes described herein are not limited to the order of operations and some operations may occur in a different order and / or as described herein. It should be understood that they may occur concurrently with other operations other than those shown and described in the specification. For example, those skilled in the art will recognize that a methodology may alternatively be represented as a series of interrelated states or events, such as a state diagram. Moreover, not all illustrated acts may be required to implement a methodology in accordance with the disclosed exemplary method.

11 shows another example of a receiver device, or alternatively, an apparatus for use in a receiver 1100 available in a system having transmitter identification information. The device 1100 may include a module 1102 for determining energy and receiving at least one PPC symbol in one or more interlaces, such as used interlace (eg, I ₁ ) and unused interlace (eg, I ₅ ). It includes. As described by connection to the communication bus 1104, the energy determination may be shared with other modules in the device 1100. This bus configuration is merely illustrative and is intended to describe that various communications are possible between the modules in device 1100.

The apparatus 1100 also includes a module 1106 for determining the WID seed from a predetermined interlace (eg, I ₁ ). As previously described, the determination of the WID may include thresholding based on previously measured energy, such as module 1102. The WID determined by module 1106 is passed to module 1108 for determining the LID from a predetermined interlace (eg, I ₀ ) using the WID. In addition, detection of the LID by module 1108 may utilize the measured energy, which is determined by module 1102.

The apparatus 1100 further includes a module 1110 for determining channel estimates from active interlaces (eg, I ₀ , I ₂ , I _4, and I ₆ ). As previously described, the determination of the channel estimate may include comparing the energy calculations of the taps with an energy threshold, such as the energy threshold determined by module 1102. Further included is a module 1112 for decoding a dedicated interlace (eg, I ₃ ) to determine transmitter identification information (TxID). As an example, the module 1112 may accomplish the process of decoding as described above in the description of block 1010 with respect to FIG. 10. In addition, a module 1114 is provided to the device 1100 for determining transmitter identity based on the TxID (and for receiving device positioning based on transmitter ID, channel estimates, and energy measurements). Module 1114 may include the functionality to perform a cyclic redundancy check to ensure that received message bits are error free, and if so, a processor such as processor 1116, which may be a DSP or other suitable processor (s). Triggers a collection of transmitter ID tables at the receiving device 1100 having measured power, LID, WID, and transmitter identification for use by the device. The transmitter ID table may be included in a memory device 1118 that communicates with modules in the processor 1116 and / or the device 1100.

The modules 1102, 1106, 1108, 1110, 1112, and 1114 are configured by at least one processor configured to execute program instructions to provide examples of a system that includes transmitter identification and positioning as described herein. Can be implemented. In one example, modules 1102, 1106, 1108, 1110, and 1112 may be implemented by the receiver logic 216 and / or PPC decoder logic 218. In one example, module 1114 is implemented by position determination logic 222. In addition, memory device 118 or equivalent computer-readable medium may be provided in association with at least one processor for storing the program instructions or code.

Various exemplary logics, logic blocks, modules, and circuits may include a general purpose processor; Digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic devices; Discrete gate or transistor logic; Discrete hardware components; Or a combination of those designed to implement these functions. A general purpose processor may be a microprocessor, but in alternative embodiments, such a processor may be an existing processor, controller, microcontroller, or state machine. A processor may be implemented as a combination of computing devices, such as, for example, a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or a combination of these configurations.

The steps and algorithms of a method or algorithm described in connection with the examples disclosed herein may be implemented directly in hardware, in a software module executed by a processor, or in a combination thereof. Software modules exist as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disks, portable disks, CD-ROMs, or any form of known storage media. An exemplary storage medium is coupled to the processor such that the processor reads information from the storage medium and writes the information to the storage medium. Alternatively, the storage medium may be integrated into the processor. The processor and the storage medium may be located in an ASIC. The ASIC may be located in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

The description of the disclosed examples is provided to enable a person skilled in the art to make and use the presently disclosed methods and apparatus. Various modifications to these disclosed examples may be readily apparent to those skilled in the art, and other examples (eg, instant messaging service or any general wireless data communication application) may be readily apparent to those skilled in the art, and the general principles defined herein may be within the spirit and scope of the present disclosure. Can also be applied. Thus, the present disclosure is not intended to be limited to the examples shown herein but is to be accorded the widest scope consistent with the novel features and principles disclosed herein. The word "exemplary" is used herein exclusively to mean "serving as one example, illustration, or illustration." Any example described herein as "exemplary" is not necessarily to be construed as preferred or preferred over other examples.

Thus, although examples of communication systems for transmitter identification have been described and described herein, it will be appreciated that the disclosed examples may be varied in various ways without departing from the spirit or essential characteristics thereof.

Claims (43)

A method for communicating transmitter identification in an interlace structure of a communication network system using positioning pilot channels (PPCs), the method comprising:
a) encoding pilot information on a first portion of the plurality of subcarriers in a PPC symbol for an active transmitter; And
b) encoding transmitter identification information on a second portion of the plurality of subcarriers of the PPC symbol,
The first portion of the plurality of subcarriers comprises at least first and second interlaces, and the second portion of the plurality of subcarriers comprises at least a third interlace,
The pilot information is scrambled using a wide area identifier in the first interlace and scrambled using the wide area identifier and local area identifier in at least the second interlaces,
At least one of the interlaces includes the transmitter identification information in the form of one or more transmitter position coordinates in an unused interlace of the second portion of the plurality of subcarriers,
Method for conveying transmitter identification. The method of claim 1,
The transmitter identification information is encoded at least in the third interlace,
Method for conveying transmitter identification. The method of claim 1,
The interlace structure is grouped into eight interlaces,
Method for conveying transmitter identification. The method of claim 3,
Wherein the transmitter location coordinates are at least one of longitude, latitude or altitude coordinates,
Method for conveying transmitter identification. 5. The method of claim 4,
Wherein the transmitter location coordinates of at least one of longitude, latitude or altitude are in the third interlace,
Method for conveying transmitter identification. The method of claim 5,
The third interlace also includes network delay information;
Method for conveying transmitter identification. The method according to claim 6,
A fixed bit PPC packet length of 80 bits is used to provide 10 blocks of 8 bits each, each of which is converted to 100 bits,
Method for conveying transmitter identification. The method of claim 7, wherein
The 80 bit PPC packet is:
Number of field bits
Packet Type 2 TxID or Other Parameters
Latitude 23 0.125 sec resolution
Hardness 24 0.125 sec resolution
Elev 10 4m Resolution
Network delay 11 micro-seconds
Allocation 3
CRC 7
Assigned as
Method for conveying transmitter identification. The method of claim 7, wherein
The 80 bit PPC packet is:
Number of field bits
Packet Type 2 TxID or Other Parameters
Transmitter ID 18
Additional bits to match the reserve 50 packet size
Allocation 3
CRC 7
Assigned as
Method for conveying transmitter identification. 9. The method of claim 8,
The packet type further includes parameters of frame number and transmitter power,
Method for conveying transmitter identification. 10. The method of claim 9,
The packet type further includes parameters of frame number and transmitter power,
Method for conveying transmitter identification. The method of claim 1, wherein encoding the transmitter identification information comprises:
Interleaving the information bits of the transmitter identification information;
Encoding the bits using a predetermined encoding scheme;
Manipulating the encoded bits to ensure that the number of bits matches a predetermined modulation scheme;
Modulating the bits in accordance with the predetermined modulation scheme; And
Mapping the modulated bits to subcarriers of the second portion of the plurality of subcarriers of the PPC symbol;
Method for conveying transmitter identification. The method of claim 12,
The predetermined encoding scheme includes Reed-Muller encoding,
Method for conveying transmitter identification. The method of claim 12,
Manipulating the encoded bits includes puncturing one or more encoded bits and replacing the punctured encoded bits with zero values.
Method for conveying transmitter identification. The method of claim 12,
Wherein the predetermined modulation scheme comprises QPSK modulation,
Method for conveying transmitter identification. The method of claim 1,
The communication system comprises an OFDM communication system,
Method for conveying transmitter identification. An apparatus for conveying transmitter identification in an interlace structure of a communications network system using positioning pilot channels (PPCs),
a) a first module configured to encode pilot information on a first portion of a plurality of subcarriers in a PPC symbol for an active transmitter; And
b) a second module configured to encode transmitter identification information on a second portion of the plurality of subcarriers of the PPC symbol,
The first portion of the plurality of subcarriers comprises at least first and second interlaces, and the second portion of the plurality of subcarriers comprises at least a third interlace,
The pilot information is scrambled using a wide area identifier in the first interlace and scrambled using the wide area identifier and local area identifier in at least the second interlaces,
At least one of the interlaces includes the transmitter identification information in the form of one or more transmitter position coordinates in an unused interlace of the second portion of the plurality of subcarriers,
Apparatus for conveying transmitter identification. 18. The method of claim 17,
The first portion of the plurality of subcarriers comprises at least first and second interlaces, and the second portion of the plurality of subcarriers comprises at least a third interlace
Apparatus for conveying transmitter identification. 18. The method of claim 17,
The interlace structure is grouped into eight interlaces,
Apparatus for conveying transmitter identification. 18. The method of claim 17,
Wherein the transmitter location coordinates of at least one of longitude, latitude or altitude are in the third interlace,
Apparatus for conveying transmitter identification. 21. The method of claim 20,
The third interlace also includes network delay information;
Apparatus for conveying transmitter identification. The method of claim 21,
A fixed bit PPC packet length of 80 bits is included to provide 10 blocks of 8 bits each, each of which is converted to 100 bits,
Apparatus for conveying transmitter identification. The method of claim 22,
The 80 bit PPC packet is:
Number of field bits
Packet Type 2 TxID or Other Parameters
Latitude 23 0.125 sec resolution
Hardness 24 0.125 sec resolution
Elev 10 4m Resolution
Network delay 11 micro-seconds
Allocation 3
CRC 7
Assigned as
Apparatus for conveying transmitter identification. The method of claim 22,
The 80 bit PPC packet is:
Number of field bits
Packet Type 2 TxID or Other Parameters
Transmitter ID 18
Additional bits to match the reserve 50 packet size
Allocation 3
CRC 7
Assigned as
Apparatus for conveying transmitter identification. A computer readable medium for communicating transmitter identification in an interlace structure of a communication network system using positioning pilot channels (PPCs),
Code for causing a computer to encode pilot information on a first portion of the plurality of subcarriers in a positioning pilot channel symbol for an active transmitter; And
Code for causing a computer to encode transmitter identification information on a second portion of the plurality of subcarriers of the symbol,
The first portion of the plurality of subcarriers comprises at least first and second interlaces, and the second portion of the plurality of subcarriers comprises at least a third interlace,
The pilot information includes code for causing a computer to scramble with a wide area identifier in the first interlace and code for causing scramble with the wide area identifier and a local area identifier in at least the second interlaces,
At least one of the interlaces comprises code for causing a computer to encode the transmitter identification information in the form of one or more transmitter position coordinates in an unused interlace of the second portion of the plurality of subcarriers;
Computer-readable media for conveying transmitter identification. 26. The method of claim 25,
The transmitter identification information is encoded at least in the third interlace,
Computer-readable media for conveying transmitter identification. 26. The method of claim 25,
The transmitter identification information comprises at least one of a transmitter identification field, a transmitter assignment field, and cyclic redundancy check bits,
Computer-readable media for conveying transmitter identification. 28. The method of claim 27,
The transmitter assignment field is configured to convey whether subsequent symbols containing additional data are to be transmitted or not;
Computer-readable media for conveying transmitter identification. 26. The method of claim 25,
Further comprising code for causing a computer to transmit transmitter allocation data in the transmitter identification information indicating the allocation of one or more subsequent symbols for a transmitter specific channel used to convey additional data;
Computer-readable media for conveying transmitter identification. 26. The method of claim 25,
Code for interleaving information bits of the transmitter identification information;
Code for encoding the bits using a predetermined encoding scheme;
Code for manipulating the encoded bits to ensure that the number of bits matches a predetermined modulation scheme;
Code for modulating the bits in accordance with the predetermined modulation scheme; And
Further comprising code for mapping the modulated bits to subcarriers of the second portion of the plurality of subcarriers of the PPC symbol;
Computer-readable media for conveying transmitter identification. 31. The method of claim 30,
Wherein the predetermined encoding scheme comprises read-muller encoding,
Computer-readable media for conveying transmitter identification. 31. The method of claim 30,
The code for manipulating the encoded bits further includes code for puncturing one or more encoded bits and code for replacing the punctured encoded bits with zero values,
Computer-readable media for conveying transmitter identification. 31. The method of claim 30,
Wherein the predetermined modulation scheme comprises QPSK modulation,
Computer-readable media for conveying transmitter identification. 26. The method of claim 25,
The communication network system comprising an OFDM communication system,
Computer-readable media for conveying transmitter identification. A computer readable medium implementing a method for conveying transmitter identification in an interlace structure of a communication network system using positioning pilot channels (PPC), comprising:
The method comprises:
a) encoding pilot information on a first portion of the plurality of subcarriers in a PPC symbol for an active transmitter; And
b) encoding transmitter identification information on a second portion of the plurality of subcarriers of the PPC symbol,
The first portion of the plurality of subcarriers comprises at least first and second interlaces, and the second portion of the plurality of subcarriers comprises at least a third interlace,
The pilot information is scrambled using a wide area identifier in the first interlace and scrambled using the wide area identifier and local area identifier in at least the second interlaces,
At least one of the interlaces includes the transmitter identification information in the form of one or more transmitter position coordinates in an unused interlace of the second portion of the plurality of subcarriers,
Computer readable medium. 36. The method of claim 35,
The transmitter identification information is encoded at least in the third interlace,
Computer readable medium. 36. The method of claim 35,
The interlace structure is grouped into eight interlaces,
Computer readable medium. 39. The method of claim 37,
Wherein the transmitter location coordinates are at least one of longitude, latitude or altitude coordinates,
Computer readable medium. The method of claim 38,
Wherein the transmitter location coordinates of at least one of longitude, latitude or altitude are in the third interlace,
Computer readable medium. 40. The method of claim 39,
The third interlace also includes network delay information;
Computer readable medium. 41. The method of claim 40,
A fixed bit PPC packet length of 80 bits is used to provide 10 blocks of 8 bits each, each of which is converted to 100 bits,
Computer readable medium. 42. The method of claim 41,
The 80 bit PPC packet is:
Number of field bits
Packet Type 2 TxID or Other Parameters
Latitude 23 0.125 sec resolution
Hardness 24 0.125 sec resolution
Elev 10 4m Resolution
Network delay 11 micro-seconds
Allocation 3
CRC 7
Assigned as
Computer readable medium. 42. The method of claim 41,
The 80 bit PPC packet is:
Number of field bits
Packet Type 2 TxID or Other Parameters
Transmitter ID 18
Additional bits to match the reserve 50 packet size
Allocation 3
CRC 7
Assigned as
Computer readable medium.

Images