MX2008004044A - Position location using transmitters with timing offset and phase adjustment - Google Patents

Abstract

Systems and methods are provided for determining position location information in a wireless network. In one embodiment, timing offset information is communicated between multiple transmitters and one or more receivers. Such information enables accurate position or location determinations to be made that account for timing differences throughout the network. In another embodiment, transmitter phase adjustments are made that advance or delay transmissions from the transmitters to account for potential timing differences at receivers. In yet another embodiment, combinations of timing offset communications and/or transmitter phase adjustments can be employed in the wireless network to facilitate position location determinations.

Description

LOCATION OF POSITION USING TRANSMITTERS WITH TIMER COMPENSATION AND PHASE ADJUSTMENT FIELD OF THE INVENTION The subject technology generally refers to communication systems and methods, and more particularly to systems and methods that determine position locations according to wireless networks by employing timing compensations or transmitter phase adjustment techniques within the networks BACKGROUND OF THE INVENTION One technology that has dominated wireless systems is the Digital Wireless Access Technology Multiple by Code Division (CDMA). In addition to CDMA, an air interface specification defines FLO technology (Only Advance Link) that has been developed by a leading group in the wireless provider industry. In general, FLO has leveraged the most convenient features of the available wireless technologies and has used the latest advances in system coding and design to consistently achieve the highest quality performance.

One goal is for FLO to be a globally adopted standard. The FLO technology was designed in one case for a mobile multimedia environment and shows convenient performance characteristics ideally for use in cellular equipment. It uses the latest advances in coding and interleaving to achieve the highest quality reception at all times, both for real-time content streams and other data services. FLO technology can provide robust mobile performance and high capacity without compromising power consumption. The technology also reduces the cost of the network for the provision of multimedia content by dramatically reducing the number of transmitters that need to be deployed. In addition, multimedia multicasting based on FLO technology complements the cellular network voice and data services of wireless operators, providing content to the same cellular equipment used in 3G networks. The FLO wireless system has been designed to transmit audio and video signals in real time, apart from non-real-time services to mobile users. The respective FLO transmission is carried out using high energy and high transmitters to ensure broad coverage in a given geographical area. In addition, it is common to deploy 3-4 transmitters in most markets to ensure that the FLO signal reaches a significant portion of the population in a given market. Due to the coverage of the FLO transmitter, it is possible to determine position locations based on triangulation techniques, for example. Traditional position location techniques make use of satellite-based GPS signals for range measurements. However, the problem with satellite-based signals is the lack of signal availability in environments within facilities, for example, where line-of-sight for satellites is not available. In contrast, FLO networks are often designed to achieve coverage within facilities, and in this way, the respective waveforms can provide positioning information to devices while they are located within facilities.

SUMMARY OF THE INVENTION The following presents a simplified summary of various modalities in order to provide a basic understanding of some aspects of the modalities. This summary is not an extensive overview. It is not intended to identify key / critical elements or delineate the scope of the modalities described here. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description presented below. Systems and methods are provided to determine location or position information through wireless networks and instead of (or in connection with) conventional Global Positioning System (GPS) techniques. In a modality, the position location in a transmission network is determined using multiple transmitters that are considered for timing differences between transmitters. Many position location algorithms assume that transmitters that emit signals used for range measurements are aligned in time using a common central clock, such as GPS, for example. However, it is convenient in some transmission systems to forward / delay transmissions from some of the transmitters with respect to the central clock in order to facilitate the reception of the signal and quality through the network. In those cases, position location algorithms make use of the timing compensation information of the transmitters to result in more precise range measurements on conventional position location components. Therefore, in some embodiments, overload parameter information may be transmitted (eg, timing compensation information), as well as the use of this additional information in the receiver to produce accurate range measurements as a result. In another embodiment, the timing of signal transmission may be advanced or delayed in the respective transmitters to alleviate the need for it to be considered for timing compensations in the receiver. By adjusting the timing of the signals transmitted on the transmitters, precise position information can be determined at the respective receivers while timing compensation calculations are mitigated because timing inequalities from a centralized clock are already have considered in the transmitters. As can be seen, some systems may include combinations of timing compensations that are communicated to the receivers and / or timing settings in the transmitters to facilitate accurate position location determinations. To achieve the foregoing as well as related purposes, some illustrative modalities are described herein in connection with the following description and the appended figures. These aspects are indicative of several ways in which the modalities can be practiced, all of which is intended to be covered by this document.

BRIEF DESCRIPTION OF THE FIGURES Figure 1 is a schematic block diagram illustrating a wireless network positioning system. Figure 2 is an exemplary system employing timing compensation information for position location determinations. Figure 3 illustrates exemplary techniques for transmitting timing compensation information. Figure 4 illustrates an exemplary system for adjusting timing information in a wireless positioning system. Figure 5 is a diagram illustrating exemplary network layers for a wireless positioning system. Figure 6 is a diagram illustrating an exemplary data and signal structure for a wireless positioning system. Figure 7 illustrates an exemplary timing process for a wireless positioning system. Figure 8 is a diagram illustrating an exemplary user device for a wireless system. Figure 9 is a diagram illustrating an exemplary base station for a wireless system. Figure 10 is a diagram illustrating an exemplary tranceptor for a wireless system.

DETAILED DESCRIPTION OF THE INVENTION Systems and methods are provided to determine location location information in a wireless network. In one embodiment, the timing compensation information is communicated between multiple transmitters and one or more receivers. This information allows precise determinations of position or location which are considered for timing differences through the network. In another mode, phase adjustments of the transmitter are made which advance or delay the transmissions from the transmitters to consider the potential timing difference between the transmitters and the common clock. In this way, position location determinations can be made if additional timing adjustments are made to the receivers. In yet another aspect, combinations of timing compensation communications and / or transmitter phase adjustments in the wireless network may be employed to facilitate calculations or position location determinations. It can be seen that the timing compensation can be considered as an inequality in timing between a transmitter clock and a common clock source which leads to synchronization symbols in the transmitter that are being transmitted to a compensation as compared to synchronization signals of a common clock. For example, in the case of Only Advance Link (FLO) signals, the super frame limit on the transmitter is generally expected to be synchronized with 1 1 PPS signal from a GPS. However, due to the timing inequality, or sometimes intentionally for network optimization purposes, the super frame boundary can actually be anticipated or delayed with respect to the 1 PPS signal from the GPS. This is referred to as timing compensation in the transmitter. With the phase adjustments in the transmitter, the waveform of the transmitter is essentially modified to regulate the propagation delay perceived by the receiver, without considering the timing compensations in the transmitter. In this case, even when the transmitter clock (and therefore the transmission) can be accurately synchronized with the common clock source, it is possible that the transmitter waveform will be modified to result in delay measurements of the transmitter. spread skewed in the receiver. For example, in the case of FLO that uses OFDM signaling, the super frame limit could be synchronized with the 1 PPS signal from GPS. However, the transmitter could adjust the transmission phase using a cyclic offset of the OFDM symbol buffer. The cyclic prefix for the OFDM symbol may be formed based on the cyclically offset OFDM symbol. With said signal modification, the delay perceived by the receiver changes with the chosen transmission phase (or equivalently, the amount of cyclic shift in the OFDM symbol). This is called phase adjustment in the transmitter. As used in this application, the terms "component", "network", "system" and the like are intended to refer to a computer-related entity, whether hardware, a combination of hardware and software, software, or running software. . For example, a component may be, but is not limited to, a process running on a processor, a processor, an object, an executable, a sequence of execution, a program, and / or a computer. By way of illustration, both an application running on a communications device and the device itself can be a component. One or more components may reside within a process and / or sequence of execution and a component may be located on a computer and / or may be distributed between two or more computers. Also, these components can run from several computer readable media that have several data structures stored in them. Components can establish communication about local and / or remote processes, such as, according to a signal that has one or more data packets (for example, data from a component that interacts with another component in a local system, distributed system). , and / or through a wired or wireless network such as the Internet). Figure 1 illustrates a wireless network positioning system 100. The system 100 includes one or more transmitters 110 that establish communication through a wireless network with one or more receivers 120. The receivers 120 can include substantially any type of communication device. such as a cell phone, computer, personal assistant, handheld device or portable devices, and so on. The system 100 employs one or more position location components 130 to facilitate the determination of a position or location for the receivers 120. In general, the timing synchronization information between the transmitters 110 and the receivers 120 may require adjustment in several modalities described here to facilitate precise determinations of location of position in the receivers. In one case, the timing compensation components 140 may be communicated between the transmitter 110 and the receiver 120 to indicate timing differences or adjustments in the wireless network that are to be considered for a component or position location determination algorithm. Another case employs phase adjustment components 150 in the transmitters 110 to advance or delay signals that have the effect of compensating for timing differences or inequalities that may occur in the system 100. In other embodiments, various combinations of timing compensation components 140 and / or phase adjustment components 150 may be used concurrently to facilitate location location determinations in the wireless network positioning system 100. As illustrated, one or more pilot symbols 154 may be provided for measurements of delay. Generally, conventional position location techniques make use of satellite-based GPS signals for range measurements. However, a problem with satellite-based signals is the lack of signal availability, such as, with environments within facilities where line-of-sight for satellites is not available. On the other hand, the high power nature of the Advance Link Only (FLO) transmission facilitates that the FLO waveform is available in environments within facilities where the GPS signal is not available. Therefore, there is an alternative to position location based on measurements taken from FLO signals when the FLO signal from multiple transmitters is available. In the following description, it can be assumed that a FLO receiver can have access to signals coming from at least three different FLO transmitters (other possible configurations), which may or may not be transmitting the same information content. The FLO network is generally displayed for the Single Frequency Network (SFN) operation mode in which the transmitters are synchronized with a common clock source. The clock source, for example, could be derived from a 1PPS signal from the GPS, for example. The FLO waveform is based on Orthogonal Frequency Division Multiplex (OFDM) signaling and can be designed under the assumption that the delay spread of a channel would be less than about 135us, for example. When multiple transmitters 110 are visible to a receiver 120, the delay spread perceived by the receiver is a function of the relative position of the receiver from various transmitters. In some cases, it is possible for the receiver 120 to be near one of the transmitters 110 and away from another transmitter thus resulting in a large delay spread. If the resulting delay spread exceeds the design specification of 135us (or other reference), it may incur a significant penalty in the performance of the system. However, it is possible to control the delay spread perceived by the receiver 120 at various points in the network by delaying or advancing a super frame boundary with respect to a synchronization pulse from the central clock. Therefore, in an optimized FLO network deployment, it may also be realistic to assume that there is a fixed timing offset between different transmitters 110. In an SFN deployment of an FLO network, the transmitters 110 are likely to be tuned to operate a timing compensation fixed with respect to a central clock (and therefore, each other) to optimize the delay spreading observed in the receiver 120 and therefore, the performance of the system. The relative timing compensations in the transmitter can adversely affect the range measurements for position location if it is not considered. However, in a mobile-based position location and network-based position location, it is possible to consider the timing compensation of the transmitter by modifying the range calculations. This may include the fact that the FLO network provides timing compensation information from the transmitter to the receiver 120 in a mobile-based position location system, adjusting the transmission timing and phase signals, or a combination of timing compensations with signal settings. Figure 2 illustrates an exemplary system 200 that employs timing compensations for position determinations. In this example, the transmitters A, B and C at 210 can be three different FLO transmitters carrying FLO signals that are within the reception range of a receiver 220 at a given point in time. In addition, assume that da, and c refer to the timing compensation 230 of the respective transmitters with respect to a common clock source 240. Here, positive compensation refers to advancing the transmission with respect to the central clock 240 while a compensation negative would refer to the delay of the transmission with respect to the central clock. It can be assumed that a receiver clock is synchronized with a common clock source 240 in phase and frequency. The FLO air interface specification, which is commonly available, allows each transmitter 210 to insert symbols (known as a pilot positioning channel) unique to the transmitter. These symbols can be designed to allow the receiver 220 to estimate the propagation delay from each of the transmitters 210. The pilot positioning channel is essentially a set of specific pilot tones to each transmitter., designed with high processing gain so that a channel with a prolonged delay spread as well as a weak energy can still be detected in the receiver 220. In the case of line of sight propagation without significant spreading from the transmitter 210 to the receiver 220, the channel estimate obtained through the positioning pilot generally comprises a simple path. The distance of the receiver 220 from the transmitter 210 is determined based on the location of the channel path in the channel estimate. In the example of system 200, assume that ta can be the location of the single path (or the first path of arrival in the case of multiple paths) in the channel estimate based on the pilot positioning channel from transmitter A. Similarly, assume that tb and tc are the delay of the first arrival path in the channel estimate from transmitters B and C respectively. If the clocks in the three transmitters 210, as well as the receiver 220, were synchronized in frequency as well as in phase, then the distance of the receiver from the transmitters is calculated as the speed of light (c) multiplied by the propagation delay measured through the channel estimate. However, in the presence of timing compensations in the transmitters 210, the delays measured in the receiver 220 should be corrected by the timing compensation 230 between the transmitter and the receiver. Therefore, the distance of the receiver from transmitter A is provided by: Sa = (da + ta) xc, where c is the speed of light. Similarly, S¿ >; = (db + tb) x c and Sc = (dc, + tc) x c. When determining the relative distance of the receiver 220 from three known locations (in this case, the known locations are the FLO transmitters), the location of the receiver can be obtained through the well-known triangulation method. The triangulation method essentially consists of determining the simple point of intersection for circles drawn around the three transmitters A, B and C with the radii Sa, Sb and Sc respectively. Therefore, it is clear that in the case of relative timing compensations in the transmitters 210, it is useful for the receiver 220 to have knowledge of the timing compensation values 230 to accurately determine the position or location. Figure 3 illustrates exemplary methods for communicating timing information 300. As can be seen, there are several possible techniques for transmitting timing compensation information 300 to a receiver. It is noted that it suffices for the receiver to be aware of the timing compensation of each of the transmitters with respect to a common central clock such as the GPS clock or other common clock. At 310, a possible transmission mechanism is for the transmitters to transmit the information regarding the timing compensation using overload symbols. For example, in the FLO system, the timing information from all the transmitters in a given local area may be contained in the OIS local area field (Overload Information Symbols) which is specific to a given local area but changes through different local areas in a given broad area. An advantage of such an approach is that the timing information of the transmitter is localized. It is noted that it may not offer an advantage for a receiver to receive timing compensation information regarding a transmitter from which the pilot positioning channel can not receive. On the other hand, the local OIS field may be more susceptible to interference at the coverage edge than the pilot positioning channel. As a result, the receiver can decode the pilot positioning channel in a successful manner at the same time that it may not be able to obtain the timing information from the local OIS channel. A variant of this approach would be to include the timing information in the wide-area OIS which would remove the edge-of-coverage problems at the expense of transmitting the transmitter timing information over a much wider geographic area (and therefore , useful bandwidth). In 320, another possible technique for transmitting timing information is to incorporate the timing information of the transmitter into the pilot positioning channel (PPC). In this case, the receiver can first estimate the channel from a given transmitter using the PPC from the transmitter and then decode the timing information incorporated in the PPC. The processing gain of the PPC may have to be increased enough in this case to facilitate that the probability of detection of the PPC is not affected in the presence of additional information incorporated in the symbols. At 330, a third possible technique for transmitting timing information is to broadcast an almanac of the transmitters as an MLC (Logical Media Channel FLO) of non-real time periodically and to enable the receivers to decode this particular information from the MLC. At 340, another attractive technique mitigates the timing compensation information in the transmitter by modifying the transmitter waveform for the PPC symbols taking the timing offsets into consideration as discussed below with respect to Figure 4. Figure 4 illustrates an exemplary system 400 for adjusting the timing information in a wireless positioning system. In this example, two transmitters A and B are shown at 410. A signal from the transmitters 410 can be advanced or delayed at 420 to consider possible timing differences in the system. Therefore, a receiver 430 can determine position locations without having to determine offsets from a centralized clock, as discussed above. The concept of advancing or delaying the transmitter timing at 420 is introduced into the FLO system to regulate the effective channel delay spread as perceived by the receiver 430. In one case, in an OFDM system, the linear convolution of the channel with the The transmitted signal can be treated as a cyclical convolution if the delay spread of the channel is smaller than the cyclic prefix used by the OFDM signal. In this example, consider transmitters A and B at 410 with timing compensations da and d. Assume that t'a may be the actual delay that would be perceived by a line of sight propagation component based on the distance between transmitter A and receiver 430. Similarly, assume that t 'b is the actual delay that would be perceived by a line of sight component from transmitter B to receiver 430. It can be seen that additional delays da and db are introduced in the transmitters when the delay spread t 'bt' a exceeds the cyclic prefix (assume a component of line of sight from each of the transmitters). With the delays da and db, in the transmitters, the signal received in the receiver is provided by: Equation 1 and (n) = ha (n) * xa (n-da) + hb (n) * xb (n-db ) + w (n), where ha (n) and xa (n) are the channel and the signal with respect to the transmitter A, * represents the linear convolutional operation and w (n) is the aggregate noise in the receiver. In the case of traffic channel in a wide area network, xa (n) and xb (n) are generally the same (say x (n)). When using the linear convolutional properties, the above equation can be written as, Equation 2 and (n) = ha (n-da) * x (n) + hb (n-db) * x (n) + w (n ) So that the perceived channel delay spread is now provided by: (t 'b-db) - (t' a-da) and can be controlled by entering timing compensations at the transmitter. When the effective delay spread is smaller than the cyclic prefix, the signal received in Equation 1 can be written as the cyclical convolution instead of a linear convolution. Therefore: Equation 3 and (n) = ha (n) ®xa (n-da) + hb (n) ®xb (n-db) + w (n), or equivalently, Equation 4 and (n ) = ha (n-da) ®xa (n) + hb (n-db) ®xb (n) + w (n) where ® denotes the circular convolution. If the cyclic prefix is long enough, then the delay operation of the signal xa (n) by da in Equation 1 to result in Equation 3 can be achieved by the circular rotation of xa (n) per day in the Equation 3. Based on the above cases, the following is proposed for the pilot positioning channel with respect to regular traffic channels. During the regular traffic channel, the cyclic prefix used is usually short (512 chips in the case of FLO) and therefore, the cyclic shift technique analyzed in Equation 3 can not be used to regulate delay spreading cash of the channel. Therefore, transmissions from the respective transmitters will be physically delayed (transmitters A and B per day and db in this example) to meet the requirements of the cyclic prefix. On the other hand, for the positioning pilot channel, a long cyclic prefix (of the order of 2500 chips in FLO, where the chips refer to the bits encoded in data packets) can be used to allow the calculation of delay to start of weak transmitters that are far away. In addition, the delays da and db introduced by the transmitters for the traffic channel affect the delay observations made in the positioning pilot channel, thus requiring this overload information in the receiver as previously analyzed. Due to the availability of a long cyclic prefix for the pilot positioning channel, the transmitter can undo the effect of the actual physical delays da and db by a cyclic shift of the positioning signal. If xa, p (n) is the intended positioning signal from transmitter A with the timing delay given, then the transmitter can send a cyclically shifted version provided by xa, p (n + da). Similarly, the cyclic displacement of the signal from transmitter B. Due to the presence of the long cyclic prefix, Equation 3 is still valid and therefore: Equation 5 and (n) = ha (n) ®xa, p (n) + hb (n) ®xb, p (n) + w (n), thus easing the need to send the transmitter's delay information to the receiver. This technique can be used to consider transmitter timing compensations that result from delays introduced as part of network planning, as well as other timing delays that may arise because of filters, cables and other components, for example. Referring to another modality, the above analysis can assume that the range measurements are being calculated in the mobile receiver. However, it is possible that the calculations are executed in the network where the timing information is available offline. In this case, the receiver can measure pseudoranges s 'a, s'b and S'c, where for example, s' a = taxc, without taking into account the timing compensation of the transmitter. The receiver would transmit the pseudorange s' a to the network and additional corrections for the timing compensations can easily be carried out in the network because the entire calendar can be made available in the network. The previous analysis assumed that the clock of the receiver is closely synchronized with the common clock and there is an inequality between the common clock and the transmitter clock because of the timing compensation or phase adjustment in the transmitter. However, it can be appreciated that this can be considered a special case and that the receiver clock does not need to be synchronized with the common clock. When the clock of the receiver is not synchronized with the common clock, the delay measurements from the respective transmitters may also include a common polarization term, which is the amount of inequality between the common clock and the receiver clock. The common polarization is now another unknown point that needs to be calculated in addition to the spatial coordinates of the receiver. The unknown points in the spatial coordinates as well as the clock polarization can be resolved with the help of measurements from additional transmitters. In particular, it is sufficient to have measurements from, for example, four different transmitters (with the timing compensation information available with respect to the common clock source and assuming that the receiver is on the surface of the earth), to solve both the spatial coordinates as the clock polarization common in the receiver. In the absence of the common clock polarization in the receiver (ie, the receiver clock is synchronized with the common clock), it is sufficient to have delay measurements from, for example, three different transmitters. Figure 5 illustrates exemplary network layers 500 for a wireless positioning system. A reference model of interface interface only of forward link (FLO) is shown in figure 5. In general, the FLO air interface specification covers protocols and services corresponding to OSI6 that have layers 1 (physical layer ) and Layer 2 (Data Link Layer). The Data Link Layer is further subdivided into two sub-layers, namely, Media Access sub-layer (MAC), and Current sub-layer. Higher layers may include multimedia content compression, access control to multimedia, along with content and formatting of control information. The FLO air interface specification usually does not specify the upper layers to allow design flexibility in support of various applications and services. These layers are shown to provide context. The Current Layer includes multiplexes of up to three upper layer flows in a logical channel, binding of upper layer packets to streams for each logical channel and provides packetization and residual error handling functions. Characteristics of the Medium Access Control (MAC) layer include access control to the physical layer, execution of the mapping between logical channels and physical channels, multiplexing of logical channels for transmission over the physical channel, demultiplexing of the logical channels in the mobile device and / or execution of Quality of Service (QOS) requirements. The physical layer characteristics include providing channel structure for the forward link, and defining frequency, modulation and coding requirements. In general, FLO technology uses Orthogonal Frequency Division Multiplexing (OFDM), which is also used by Digital Audio Transmission (DAB) 7, Digital Terrestrial Video Transmission (DVB-T) 8, and Digital Transmission Services Integrated Terrestrial (ISDB-T) 9. In general, OFDM technology can achieve high spectral efficiency while effectively meeting mobility requirements in a large-cell SFN. Also, OFDM can handle long delays from multiple transmitters with a convenient cyclic prefix length; a protection interval added to the front of the symbol (which is a copy of the last portion of the data symbols) to facilitate orthogonality and mitigate inter-carrier interference. As long as the length of this interval is greater than the maximum channel delay, the reflections of previous symbols are removed and the orthogonality is maintained. Proceeding with Figure 6, a FLO 600 physical layer is illustrated. The FLO physical layer uses a 4K mode (which produces a transform size of 4096 subcarriers), providing superior mobile performance as compared to an 8K mode, at the same time as a sufficiently long protection interval is retained which is useful in fairly large SFN cells. The rapid channel acquisition can be achieved through an optimized interleaver and pilot structure design. The interleaving schemes incorporated in the FLO area interface facilitate time diversity. The designs of interval and pilot structure optimize the use of channel without this causing any discomfort to the user with long acquisition times. In general, the signals transmitted by FLO are organized in super frames as illustrated in 600. Each super frame is compressed into four data frames, including TDM (Time Division Multiplexed) pilots, Overload Information Symbols (OIS). ) and tables that contain data of wide area and local area. The TDM pilots are provided to allow a quick acquisition of the OIS. The OIS describe the location of the data for each media service in the super frame. Typically, each super frame consists of 200 OFDM symbols per MHz of allocated bandwidth (1200 symbols per 6 MHz), and each symbol contains 7 interlaces of active subcarriers. Each interleaving is evenly distributed in frequency, so that it achieves full frequency diversity within the available bandwidth. These interlaces are assigned to logical channels that vary in terms of duration and number of real interlaces used. This provides flexibility in the diversity of time achieved by any given data source. Lower data transfer rate channels can be assigned a lower number of interleaves to improve time diversity, while higher data rate channels use more interleaving to minimize radio turn-on time and reduce energy consumption. The acquisition time for both high and low data transfer rate channels is generally the same. Therefore, the diversity of time and frequency can be maintained without compromising the acquisition time. Most often, FLO logical channels are used to carry content in real time (live stream) at variable speeds in order to obtain possible multiplexing statistics statistics with variable speed codecs (Compressor and Decompressor in one). Each logical channel can have different coding and modulation speeds to support a variation of reliability and quality of service requirements for different applications. The FLO multiplexing scheme allows device receivers to demodulate the content of the simple logical channel in which they are interested in minimizing energy consumption. Mobile devices can demodulate multiple logical channels concurrently to allow the associated video and audio to be sent on different channels. The coding and error correction techniques can also be used. In general, FLO incorporates a turbo inner code 13 and an outer code 14 of Reed Solomon (RS). Typically, the turbo code package contains a Cyclic Redundancy Review (CRC). The RS code does not need to be calculated for data that is received correctly, which, under favorable signal conditions, result in additional energy savings. Another aspect is that the FLO air interface is designed to support 5, 6, 7 and 8 MHz frequency bandwidths. A highly desirable service offer can be achieved with a simple Radiofrequency channel. Figure 7 illustrates a position and location process 700 for wireless systems. Although for purposes of simplicity of explanation, the methodology is shown and described as a series or number of acts, it will be understood and appreciated that the processes described here are not limited by the order of the acts, since some acts may occur in different orders and / or concurrently with other acts to those shown and described here. For example, those skilled in the art will understand and appreciate that a methodology could alternatively be represented as a series of interrelated states or events, such as in a state diagram. In addition, not all illustrated acts may be required to execute a methodology in accordance with the subject methodologies described herein. Proceeding with 710, various timing corrections are determined. This may include executing calculations to determine timing differences between transmitters, receivers and / or a centralized clock source. These differences can be used to determine timing offsets that can be used in receivers to correct differences with a clock, or such calculations can be used to determine how far forward or delayed the transmissions of the transmitter to consider the timing differences. The test devices can be used to monitor potential system changes, where feedback is received from said devices to facilitate the determination of compensations or transmitter signal adjustments. At 720, one or more time offsets are transmitted as part of a data packet to indicate how the potential receiver should adjust location or position calculations. Alternatively, the signals can be advanced or delayed by 730 to consider timing differences in the wireless network and in reference to a centralized clock. As can be seen, both approaches in 720 and 730 can be applied concurrently. For example, it may be convenient to transmit constant time compensations at 720 and use an advance or signal delay adjustable at 730 if the electrical or environmental conditions change. These changes can be monitored and closed loop mechanisms can be used to automatically adjust transmissions or system timing. In another aspect, an advance or delay in the transmission timing can be applied as a constant and dynamic time compensations can be calculated and transmitted in 720 to consider potential detected changes. At 740, compensations for time and / or adjusted or corrected signals are received. As noted above, time compensations can be received, signals adjusted with respect to a clock can be received, or combinations of time compensations and adjusted signals can be received. In 750, time compensations and / or signals adjusted in phase are used to determine a position in a receiver or receivers. Such information can be used to automatically calculate position location information that is considered for differences that may occur between clocks and reference sources. For example, time compensations or signals adjusted in phase can be received within facilities to determine the position of a receiver. Figure 8 is an illustration of a user device 800 that is employed in a wireless communication environment, in accordance with one or more aspects stipulated herein. The user device 800 comprises a receiver 802 that receives a signal from, for example, a receiving antenna (not shown), and performs typical actions on it (for example, filters, amplifies, subverts, etc.) the received signal and digitizes the conditioned signal to obtain samples. The receiver 802 may be a non-linear receiver, such as a maximum likelihood receptor (ML) -MMSE or the like. A demodulator 804 can demodulate and provide received pilot symbols to a processor 806 for channel estimation. An FLO channel component 810 is provided to process FLO signals as previously described. This may include placement location calculations and / or digital current processing among other processes. The processor 806 may be a processor dedicated to analyzing information received by the receiver 802 and / or generating information for transmission by a transmitter 816, a processor controlling one or more user device components 800, and / or a processor that analyze information received by receiver 802, generate information for transmission by transmitter 816, and control one or more user device components 800. User device 800 may additionally comprise memory 808 that is operatively coupled to a processor 806 and storing information related to ranges calculated for user device 800, a range calculation protocol, search boxes comprising information related thereto, and any other information suitable for supporting sphere-list decoding to calculate range in a non-linear receiver in a wireless communication system such as here It described. The memory 808 can additionally store protocols associated with range calculation, matrix generation, etc., so that the user device 800 can employ stored protocols and / or algorithms to achieve range determination in a non-linear receiver such as described here. It will be appreciated that the data storage components (eg, memories) described herein may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. By way of illustration, and not limitation, the non-volatile memory may include read only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable ROM (EEPROM), or fast memory. Volatile memory can include random access memory (RAM), which acts as an external cache. By way of illustration and not limitation, RAM is available in many forms such as synchronous RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual rate data transfer SDRAM (DDR SDRAM), enhanced SDRAM ( ESDRAM), Synchronous Link DRAM (SLDRAM), and direct Rambus RAM (DRRAM). The memory 808 of the subject systems and methods is intended to encompass, without being limited to, these and other convenient types of memory. The user device 800 further comprises a background monitor 814 for processing the FLO data, a symbol modulator 814 and a transmitter 816 transmitting the modulated signal. Figure 9 illustrates an exemplary system 900 comprising a base station 902 with a receiver 910 that receives signals from one or more user devices 904 through a plurality of receive antennas 906, and a transmitter 924 that transmits to one or more user devices 904 through a transmission antenna 908. The receiver 910 can receive information from the receiving antennas 906 and is operatively coupled with a demodulator 912 that demodulates the received information. The demodulated symbols are analyzed by a processor 914 that is similar to the processor described above with reference to FIG. 8, and which is coupled to a memory 916 that stores information related to the user ranges, search boxes related to the same, and / or any other convenient information related to the execution of the various actions and functions stipulated herein. Processor 914 is further coupled to an FLO channel component 918 which facilitates the processing of the FLO information associated with one or more respective user devices 904. A modulator 922 can multiplex a signal for transmission by a transmitter 924 through transmission antenna 908 to user devices 904. FLO channel component 918 may append information to a signal related to an updated data stream for a particular transmission stream for communication with a user device 904, which may be transmitted to the user device 904 to provide an indication that a new optimal channel has been identified and recognized. In this way, the base station 902 can interact with a user device 904 that provides FLO information and employs a decoding protocol in conjunction with a non-linear receiver, such as a ML-MIMO receiver, and so on. Figure 10 shows an example wireless communication system 1000. The wireless communication system 1000 shows a base station and a terminal for brevity purposes. However, it will be appreciated that the system may include more than one base station and / or more than one terminal, wherein additional base stations and / or terminals may be substantially similar or different from the exemplary base station and terminal described continuation. Referring now to Figure 10, in a downlink, at access point 1005, a transmission data processor (TX) 1010 receives, formats, codes, intersperses and modulates (or maps in symbols) traffic data and provides modulation symbols ("data symbols"). A symbol modulator 1015 receives and processes the data symbols and pilot symbols and provides a stream of symbols. A symbol modulator 1020 multiplexes pilot and data symbols and supplies them to a transmitter unit (TMTR) 1020. Each transmit symbol can be a data symbol, a symbol, pilot, or a signal value of zero. The pilot symbols can be sent continuously in each symbol period. The pilot symbols can be multiplexed by frequency division (FDM), multiplexed by orthogonal frequency division (OFDM), multiplexed by time division (TDM), multiplexed by frequency division (FDM), or multiplexed by code division (CDM). TMTR 1020 receives and converts the symbol stream into one or more analog signals and additionally conditions (eg, amplifies, filters, and overconverts in frequency) the analog signals to generate a convenient downlink signal for transmission over a wireless channel. The downlink signal is then transmitted through an antenna 1025 to the terminals. At terminal 1030, an antenna 1035 receives the downlink signal and provides a received signal to a receiving unit (RCVR) 1040. The receiving unit 1040 conditions (eg, filters, amplifies and subverts in frequency) the received signal and digitizes the conditioned signal to obtain samples. A symbol demodulator 1045 demodulates and provides received pilot symbols to a processor 1050 for channel calculation. The symbol demodulator 1045 further receives a frequency response estimate for the downlink from the processor 1050, performs demodulation of data in the received data symbols to obtain estimates of data symbols (which are estimates of the transmitted data symbols). ), and provides the data symbol estimates to an RX 1055 data processor, which demodulates (i.e., unmaps into symbols), deinterleaves and decodes the data symbol estimates to retrieve the transmitted traffic data. The processing by the symbol demodulator 1045 and the data processor RX 1055 is complementary to the processing by the symbol modulator 1015 and the data processor TX 1010, respectively, at the access point 1005. In the uplink, an data processor TX 1060 processes traffic data and provides data symbols. A symbol modulator 1065 receives and multiplexes the data symbols with pilot symbols, performs modulation and provides a stream of symbols. A transmitter unit 1070 then receives and processes the symbol stream to generate an uplink signal, which is transmitted by the antenna 1035 to the access point 1005. At the access point 1005, the uplink signal from the terminal 1030 is received by antenna 1025 and processed by a receiving unit 1075 to obtain samples. A symbol demodulator 1080 then processes the samples and provides received and estimated pilot symbols of data symbols for the uplink. A RX data processor 1085 processes the data symbol estimates to retrieve the traffic data transmitted by the terminal 1030. A processor 1090 performs channel estimation for each active terminal transmitting on the uplink. Multiple terminals can transmit pilots concurrently in the uplink in their respective assigned sets of pilot sub-bands, where the sets of pilot sub-bands can be interleaved. Processors 1090 and 1050 direct (for example, control, coordinate, manage, etc.) the operation at access point 1005 and terminal 1030, respectively. The respective processors 1090 and 1050 can be associated with memory units (not shown) that store program codes and data. Processors 1090 and 1050 can also execute calculations to derive pulse response and frequency estimates for the uplink and downlink, respectively. For a multiple access system (for example, FDMA, OFDMA, CDMA, TDMA, etc.), multiple terminals can transmit concurrently in the uplink. For such a system, the pilot sub-bands can be shared between different terminals. Channel estimation techniques can be used in cases where the pilot subbands for each terminal cover the entire operating band (possibly except for band edges). Said pilot subband structure would be desirable to obtain frequency diversity for each terminal. The techniques described herein can be executed through various means. For example, these techniques can be executed in hardware, software or a combination thereof. For a hardware execution, the processing units used for channel estimation can be executed within one or more specific application integrated circuits (ASIC), digital signal processors (DSP), digital signal processing devices (DSPD), programmable logic devices (PLD), field-programmable gate arrays (FPGA), processors, controllers, microcontrollers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. With software, the execution can be through modules (for example, procedures, functions and so on) that execute the functions described here. The software codes can be stored in a memory unit and can be executed through the 1090 and 1050 processors. For a software execution, the techniques described herein can be executed with module (for example, procedure, functions and so on). ) that execute the functions described here. Software codes can be stored in memory units and can be executed by processors. The memory unit can be executed inside the processor or outside the processor, in which case it is communicatively coupled to the processor through various means as is known in the art. What has been described above includes exemplary modalities. Of course, it is not possible to describe every conceivable combination of components or methodologies for purposes of describing modalities, but one skilled in the art can recognize that many additional combinations or permutations are possible. Accordingly, these modalities are intended to cover all those alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term "includes" is used in the detailed description or in the claims, said term is intended to be inclusive in a manner similar to the term "comprising", since "comprising" is interpreted when employed as a word of transition in a claim.

Claims (32)

NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following is claimed as a priority: CLAIMS

1. - A method for determining position information in a wireless network, comprising: determining time compensation information between a common clock and at least one other clock; adjusting a phase of at least one transmitter based, in part, on the time compensation information; and determining a position for the receiver based, in part, on the time offset information or the adjusted phase of the transmitter.

2. The method according to claim 1, characterized in that the common clock is based on a signal from the global positioning system.

3. The method according to claim 1, further comprising communicating the timing compensation information to at least one receiver.

4. - The method according to claim 3, further comprising transmitting the timing compensation information in a network of Advance Link Only (FLO); and advancing or delaying the transmitter timing in an Advance Link Only network to regulate an effective channel delay spread as perceived by the receiver.

5. The method according to claim 4, characterized in that the FLO network is displayed for Single Frequency Network (SFN) operation mode wherein the transmitters are synchronized to a common clock or execute a linear channel convolution with a transmitted signal.

6. The method according to claim 1, further comprising generating at least two timing compensations.

7. The method according to claim 6, further comprising controlling a delay spread by delaying or advancing a signal with respect to a synchronization pulse from a common clock.

8. - The method according to claim 6, further comprising establishing a fixed timing compensation at least between two transmitters.

9. - The method according to claim 6, further comprising sending a positive or negative parameter to indicate an advance or a delay of a transmission with respect to a common clock or delaying transmissions from the transmitters to satisfy the requirements of the cyclic prefix.

10. The method according to claim 9, further comprising employing a long cyclic prefix to allow a delay estimate from the transmitters that are remote.

11. The method according to claim 1, further comprising determining a relative distance of a receiver from three or more known locations through triangulation methods.

12. A method for determining position information in a wireless network system, comprising: determining at least one timing compensation between a receiver and a transmitter by virtue of a common clock source in a wireless network system; transmit the timing compensation to the receiver or modify a signal on the transmitter by virtue of the common clock source; and calculate a position in the receiver based on the timing compensation or the modified signal.

13. - The method according to claim 12, further comprising transmitting the timing compensation using overload symbols, in a Local Area Overload Information Symbol field, or a Wide Area Overload Information Symbol field.

14. The method according to claim 12, further comprising incorporating the timing compensation in a positioning pilot channel (PPC).

15. The method according to claim 13, further comprising transmitting an almanac of transmitters having timing compensation or broadcasting one or more pseudoranges to the transmitter's almanac.

16. A wireless positioning system, comprising: means for determining a timing compensation between a common clock and at least one other clock in a wireless network; means for transmitting the timing compensation in the wireless network; and means for altering a transmitter signal phase or a transmitter signal frequency based, in part, on timing compensation.

17. - The system according to claim 16, further comprising means for determining a location for a device based, at least in part, on the timing compensation, the signal phase of the transmitter, or the signal frequency of the transmitter .

18. A machine readable medium having machine executable instructions stored therein, comprising: determining timing differences between a common clock with respect to a subset of transmitter clocks; communicate the timing differences to at least one receiver; and adjust the transmitter clocks based, in part, on the timing differences.

19. The machine-readable medium according to claim 18, further comprising determining a location for the receiver based on the adjusted transmitter clocks or the determined timing differences.

20. The machine readable medium according to claim 18, further comprising employing triangulation techniques with the subset of transmitter clocks to determine the location.

21. - The machine-readable medium according to claim 18, further comprising a component for executing calculations in order to determine timing differences between transmitters, receivers, or a global positioning clock source.

22. The machine-readable medium according to claim 21, further comprising a component for determining how far forward or delayed the transmissions of the transmitter in order to consider timing differences.

23. The machine-readable medium according to claim 18, further comprising providing one or more test devices to monitor the potential changes of the system, wherein the feedback is received from the test devices to facilitate the determination of offsets. or transmitter signal settings.

24. The machine-readable medium according to claim 18, further comprising a component for transmitting constant time offsets and using an adjustable signal source to advance or delay the timing when the electrical or environmental conditions change.

25. The machine-readable medium according to claim 24, further comprising changing time compensations or signal timing based on closed-loop mechanisms. 26.- A machine-readable medium having a data structure stored therein, comprising: determining timing compensations between a common clock with respect to a subset of transmitter clocks; store the timing offsets in at least one data field; and determining a transmitter signal phase or frequency setting for at least one device based in part on the timing compensations in the data field. 27. The machine-readable medium according to claim 26, further comprising a layer component having at least one of a physical layer, a current layer, a media access layer, and an upper layer, the other physical layer comprises at least one of a frame field, a pilot field, an overload information field, a wide area field, and a local area field. 28. The machine-readable medium according to claim 27, further comprising a component for determining a position at least for a wireless device. 29. A wireless communication apparatus, comprising: a memory that includes a component for determining a time base from the time compensation parameters received over a wireless network; and a processor that determines a position at least for a receiver based on the time compensation parameters or from the phase or signal adjustments received from at least one transmitter. 30. The apparatus according to claim 29, further comprising one or more components for decoding a data stream of only forward link, time compensation parameters, or adjusted transmitter signals. 31.- An apparatus for operating base station resources in a wireless positioning network, comprising: means for determining timing compensations for a set of transmitters; means for communicating timing compensations to at least one receiver; and means for adjusting a signal phase or a signal frequency for the set of transmitters by virtue of the timing compensations. 32. The apparatus according to claim 31, further comprising means for coordinating with the receiver in order to determine a position for the receiver based on the timing compensations or the phase of the adjusted signal and signal frequency.