TW421941B - Method and system for facilitating timing of base stations in an asynchronous CDMA mobile communications system - Google Patents

Abstract

A method and system are disclosed for facilitating the timing (e.g., the known relative timing differences) of base stations (BSs) in asynchronous CDMA mobile communications systems. A plurality of mobile stations (MSs) measure the relative time differences between various pairs of BSs, and these measurements are stored by the BSs. A source BS sends to an MS, in a neighbor list message, estimates of the relative time difference between the source BS and each of the BSs on the neighboring cell list. Each BS on the list can maintain a relative time difference estimate table, which can be updated continuously from the reports received from MSs. Subsequently, the BSs can send entries from this table to the MS in the neighbor list message. Using this novel technique, the BSs have known relative timing differences. Consequently, when the MS initiates a cell-search for a candidate BS, the MS already has an estimate of the timing of that BS as compared to its source BS. As such, the resulting cell-search procedure has a lower level of complexity and thus can be accomplished much quicker than with prior procedures. In addition, the relative time difference estimates can be compared with corresponding time differences that are measured by a second mobile station. Based on this comparison, the propagation delays of signals between the second MS and various BSs can be calculated to determine the position of the second MS.

Description

9/1 V. Description of the invention (1) Related patents This patent claims the application of US Provisional Patent Application No. 60 / 074,494 filed on February 12, 1998. BACKGROUND OF THE INVENTION The present invention relates generally to mobile communication paradigms, and more specifically, to a method and system for facilitating base station timing in a non-synchronous coded multi-directional proximity (CDMA) mobile communication system. Description of related technologies Direct DS CDMA (DS-CDMA) mobile communication system can be an inter-cell synchronous or inter-cell asynchronous system. In other words, the base stations (BSs) in the inter-cell synchronization system are continuously synchronized with each other, while the base stations in the inter-cell asynchronous system are not synchronized with each other. More specifically, non-synchronized base stations do not share a common time reference and its transmission, and therefore have unscheduled times that are arbitrarily related to each other. An example of a cell-to-cell simultaneous system is the North American IS-95 system. Examples of intercellular asynchronous systems are the wideband CDMA (WCDMA) systems proposed in the CODIT, ETSI SMG2 Group Alpha, and ARIB specifications.

-The main disadvantage of the Λ U cell-to-cell simultaneous system is that the base station must be perfectly synchronized (down to the As level). The high level of accuracy typically provided is through the use of highly accurate time references that coexist with the base station, such as a Global Positioning System (GPS) receiver. However, due to the linear radio wave characteristics of satellite signal transmission, the use of co-existing references may not be realized at base stations located in the ground, buildings, or tunnels. Another related disadvantage is the GpS system

ii iy ·, · i; j 5. Description of the invention (2) The system of control is controlled by the government unit. As a result, the use of GPS receivers synchronized by the base station network is not welcome in some countries. These shortcomings are the main reasons why the intercellular asynchronous system is considered at this stage. For the correct operation of the asynchronous cell-to-cell system, there are two decisive functions that need to be explained: (1) soft handover (S0H0s); and unit search.

Ii In the SOHO state, the mobile station (MS) communicates with multiple base stations simultaneously. To assist SOHO s, the mobile station must scan other base stations nearby. This allows the mobile station to monitor the quality of the signals received from the multi-base stations and determine the time delay of the base stations. For the occurrence of s〇H〇, the mobile station to be delivered must be able to receive at the same time as the "source" and "target" of the base station signal, the base station signal, in order to reduce the buffer Demand (that is, a smaller time difference between base station signals requires less buffer area than a larger time difference). Furthermore, the target base station must be able to look for signals from the mobile station without having to deal with unreasonable expenditure of resources. These S0H0 publications address asynchronous systems by each call " synchronous technology, which was published by A. Baier et al. In IEEE JSAC, Step 12, Volume 733-743 in May 1994. Application Name " A Design Study for a CDMA-Based Third Generation Mobile

Radio System ". By using this technology, the mobile stations included in SOHO will calculate and report the network time difference between the target base station and the source base station1. The network will notify the target base station via the base station controller (BSC) or radio network controller (RNC) about the time difference. Then, the target base station can adjust the reception and transmission time of the intended signal of the included mobile station to Compensate for time differences.

Page 9 42 1 94 1 jMi 5. Description of the invention (3) Similar known SO HO technology will be used, where the mobile station will report the time difference between the transmission of the target base station and its transmission, rather than between the target base station and the The difference between source base station transmissions. However, since the relationship between the mobile station's transmission / reception is finally fixed, the two above-mentioned soho technologies are essentially the same / these technologies are called action assisted delivery (MAH〇) ^ In other words, The target base station to compensate for the time difference between the target base station and the source base station. Cellular unit search is usually a reference procedure, so that the mobile station can complete synchronization with the chip, time slot, and data frame of the base station, and detect the downstream line scrambling code of the base station. This procedure uses the idle or active mode during power-on (initial synchronization) and subsequently when the mobile station is looking for a SOHO candidate base station. In a synchronous system, the cell search can be performed efficiently (i.e., with relatively low complexity) because the same scrambling code can be used by the base station. Similarly, a mobile station can only perform a full base station search using a signal that matches a filter (or similar function). However, this same technology cannot be used in non-synchronous systems because different base stations

Use different scrambling codes. As a result, a low-complexity, fast unit search procedure D for asynchronous CDMA systems is required + a fast, multi-step unit search procedure for asynchronous CDMA systems has been proposed, whereby each base station can transmit an unmodulated symbol. This transmission symbol is spread by a well-known short code in each time slot of each data frame without using a scrambling code. In one such proposal, this symbol is represented as " perch i code curtain symbol (LCMS) " ^ On the second proposal, this symbol is represented as " primary synchronization channel " or primary (SCH). With the proposed multi-step procedure, page 10 V. Description of the invention (4) " '' " By using a single matching filter in accordance with the main SCH, the mobile station can thus find the base station's chip- and time slot . Subsequently, the mobile station must still look for the data frame timing and downlink scrambling code of the base station (it expands a data frame with the proposed # 步 Driver). The mobile station can find the data frame timing of the base station by detecting the second media transmission symbol, and the second transmission symbol is marked with "Perch 2 LCMS" or "Second SCH". The second symbol is transmitted in parallel with the first symbol, but the second symbol is extended by the second short code (again, no scrambling code is used). The second symbol also has a unique repeating modulation pattern in each data frame, and by After testing this pattern, the mobile station can determine the data frame timing of the base station. The spreading code factory used for the second symbol) indicates the actual scrambling code used by the possible scrambling code group belonging to the mobile station. The mobile station can then Used by correlation with the scrambling code, which is a group of indications at the identified frame timing (or at a different frame timing) identified above. However, the proposed multi-step procedure The problem is that the complexity of the unit search is still quite high, especially in the case of soho candidate search (mobile stations must be performed regularly). Another problem with the cell-to-cell synchronization system is the time between base stationsIt is not easy to determine the location of such mobile stations. Mobile communication systems that can determine the location of mobile stations in the system will gradually increase. At this stage, mobile positioning is usually performed through the use of external systems such as GPS systems. However, Ideally, the mobile niches will be performed by a cellular system without such an external system. To perform such a cellular positioning, the required method is to be able to correctly determine the difference between the mobile station and several of them. The absolute or relative distances between base stations. These distances can be

Page 11 4 21 9 ^ -1 ″ 虮 5. Description of the invention (5) Each of the available time of TO (TO) measurement. For example, the distance is borrowed as if the measurement can be used in directions that cannot be calculated in combination with each setting. The other party decided to calculate the base station in this TD0A, and provide the mobile station in the simplest station. The relay between these is divided into triangles for it to include non-required absolute time systems. The base position of the physical location is calculated by measuring the transit time, arrival time, or time difference of arrival (TD0A) on signals transmitted between different base stations. Once these are available, many rule systems can be used to calculate the geographic location of the mobile station. According to the TOA method, each mobile station from the mobile station to the base station is obtained by using TOA measurements. The radius of the circle relative to the base station for each distance at the concept center. In other words, TO A determines the light range of a mobile station from a particular base station, but determines a single TOA measurement; therefore, the mobile station can be located anywhere on the circumference defined by the path. However, by determining the circular intersection of different base stations, the position of the mobile station can be determined. The TD0A method uses ^ 0 difference between the two base stations and the TD0A between the two base stations. The position of the mobile station is then estimated along a curve, i.e. a hyperbola. This can be obtained by using three or more such curves. In the positioning technology of the approximate positions of the intersection of these curves, the S0H0 system is used in many base stations. During each handover process, the time of each base station and mobile station can be measured. Shape position. This positioning method is the easiest to implement, with very small mobile radio design changes. In addition, the base stations are not referenced; that is, this method can be used in non-synchronized cells and 'because of the geographical separation between the base stations, two other site handovers can only be used in rare cases. In other words, when approaching a base station, there are SOHs of other base stations.

Page 12 421941 m 5. Description of Invention (6) " " 'It is often impossible. This is because the "learning capability" between the mobile station and the multi-base station is normally unsatisfactory. &Quot; Another possible solution is to use an antenna array on the base station. When the base station has an antenna When arranging, the position of the mobile station can be calculated by estimating the direction of the uplink signal transmission and measuring the back-and-forth delay of the communication signal. In this method, the mobile station only needs to communicate with the base station to calculate the position. However, the positioning The purpose and widely used antenna is responsible. In addition, the multipath transmission characteristics of the uplink and downlink signals often make the antenna arrangement unpopular, especially in urban areas, whose signals are often reflected by AOpen and other structures. '

As mentioned above, GPS can be integrated into a mobile station without the need for an additional radio receiver. However, this method needs to emphasize the calculation and increase the complexity of the receiver in the mobile station. S Another solution is to measure the transit time, TOA, or TDOA of the signal transmitted from the base station to the mobile station or from the mobile station to the base station. For example, a downlink solution can be used. In the case of CDMA, the mobile station will measure the TO A of the pilot channel data, which is transmitted by several different base stations. Or the 'uplink solution' method can be used, each of which can measure the TOA of the signal transmitted by the mobile station to the multiple base stations »However, these two methods require absolute or correct relative time reference in base station synchronization. So the solution of the 'downlink and uplink' normally requires additional hardware in asynchronous networks (for example, a GPS receiver at the base station to get the timing of the base station). System and method need to reduce unit searches and actions on asynchronous networks

421 94 1 j 碥

The search rate during the positioning process makes the previous search as profitable as possible, and in brief, the present invention is successful. Searching for information to help reduce the solution of action positioning to solve the above problems. In particular, its advantages are complexity and increased unit search methods. The following detailed description of the method and system is provided to facilitate the timing of base stations in non-uniform #cdma mobile communication systems, so that the source Bsc (or RNC) is transmitted to the source base station and the source list on the adjacent list 70. The mobile station (for example, in a neighbor unit list message) estimates of the relative time difference (RTD) between each of the base stations. For the purpose of SOHO, multiple mobile stations can report estimated RTDs along with the quality information of neighboring base stations (1.) to each base station on the network. And RTD estimation table, which can be continuously updated from reports received by the mobile station. The 'base station can then transmit the registration from this βTI) estimate to the mobile station in the neighbor unit list message along with the relative scrambling code. By using this new technology, base stations are known as relative time differences. As a result, when the mobile station started a single TG search for a potential target base station, compared with the source base station of the mobile station, the mobile station already had a timing estimate for the base station. Similarly, the result unit search procedure used in asynchronous CDMA systems has lower complexity, and thus can complete previous procedures faster. j In another aspect of the present invention, the accuracy of estimating RTd can be significantly improved by specifying that y is used to estimate the propagation delay between the mobile station and the base station of the RTD. These improved RTDs can be used to further improve the timing estimates used to perform unit searches. The modified RTDs can also be used to calculate mobile station positions in mobile communication systems. Once you know the high-precision ^! ^, In action

Page 14 421941 j ^ j 5. Description of the invention (8) The distance between the base station and several base stations can be easily adjusted by using the transmission time of the signal path between the mobile station and the several base stations, TOAs Or TDOAs. An important technical advantage of the present invention is that adjacent base stations in asynchronous CDMA mobile communication systems already know the relative time difference. Another important technical advantage of the present invention is that the hardware and software complexity of the mobile station in the asynchronous CDMA mobile communication system can be reduced. However, another important technical advantage of the present invention is that in the case of asynchronous CDMA operation, the complexity of the whole unit search procedure in the communication system is significantly reduced. However, another important technical advantage of the present invention is that in the case of asynchronous CDMA operation :) The unit search speed performed in the communication system is significantly increased compared to the previous procedure. Through simple calculations on the data obtained by Gu Yi, the mobile positioning of another important technical advantage of the present invention can be determined in an asynchronous mobile communication system without the need for an external system. Brief description of the drawings The method and device of the present invention can be fully understood by referring to the following detailed description and accompanying drawings, wherein: FIG. 1 is a diagram illustrating an operation for asynchronous CDMA according to a preferred embodiment of the present invention. FIG. 2 is a simplified block circuit diagram of an example of a mobile communication system for implementing the method shown in FIG. 1 according to a preferred embodiment of the present invention. Fig. 3 is about to enter 8〇} 10 and according to a preferred embodiment of the present invention;

Page 15 421 94 1 ^ V. Description of the invention (9) Simplified block circuit diagram of a mobile station for promoting improved base station timing calculations in a non-identical #CDMA mobile communication system; Figure 4 is a SOHO included in the description in Figure 3 Signal relative timing diagram of the plot; and FIG. 5 is an exemplary flowchart illustrating a method for determining the position of a mobile station according to a specific embodiment of the present invention. Detailed description of the drawings The preferred embodiments of the present invention and its advantages can be better understood by referring to the drawings of Figs. 1-5. The same numbers are used for the same parts of different drawings. Essentially, in an asynchronous CDMA system, the base station " knows " the downlink scrambling codes of all the base stations. Typically, the list of adjacent units is broadcast in each unit (mobile station operating in interlace mode) or transmitted on a dedicated control link (mobile station operating in active mode). When the mobile station receives information about neighboring units, it determines the scrambling codes of the neighboring units listed in the potential 3101 candidates. The knowledge of scrambling code information with candidate soho units can make the mobile station reduce the entire soho unit search time (or complex f because: the number of scrambling codes of two energy can be synchronized with the original (power on) The number b is smaller than y. ^ However, the scrambling code set searched by the mobile station is smaller, and the mobile station still does not know the timing of these codes. The 6 is incorrect. This is why the currently proposed asynchronous system unit search conference information system The main reason for the unit search time (and more complex) is the same as in the present invention. The source RT transmits the estimated RTD between the neighboring cell and each of these base stations to the mobile station. And the solution has no timing information problem β In other words °

Page 16 V. Description of the invention (10) Instead of transmitting only the scramble code of the neighboring base station to the mobile station, the source base station also transmits each of the estimated RTDs. For the purpose of S0H0, the mobile station can Signal quality information (for example, signal strength, signal-to-interference ratio, or SIR, etc.) and estimated values of neighboring base stations (on a general basis, triggered by certain events, or requirements from the BSC) to network. Du Guo, each BSC can maintain the RTD estimation table, and this estimation table can be continuously updated from the RTD report received by the mobile station. In a preferred embodiment of the present invention, the 'RTD estimation table is maintained on the BSC database. Subsequently, these BSCs can transmit the registration from this RTD estimation table and the relative scrambling code (BSC maintains the estimated RT that has been transmitted to the mobile station in the previous message]) information (tracking) to the action in the neighbor unit list message station. With the use of new technologies, these base stations are known of relative time differences. As a result, in a specific embodiment, when the mobile station starts searching for potential target base stations, the mobile station already has the base station (ie, from the RTD message) timing estimation compared with its source base station. The result unit search procedure used in synchronous CDMA systems can be completed faster than the previous procedure. When the mobile station is synchronized with the potential target base station, the mobile station has an improved RTD estimate, and the mobile station can report back to the source base station in sequence (ideally with the quality information of the potential target base station). The source base station (or its base, BSC) can then update this entry in the RTD estimation table. More specifically, FIG. 1 is an exemplary method 1 for describing the base station timing and increasing the parent transfer rate in the asynchronous CDMA mobile communication system according to a preferred embodiment of the present invention. 〇 flow chart. At step 104 of the example method shown in Figure 1, the BSC system uses the phase scramble

V. Description of the invention (11) codes and complex RTD estimates between the source base station and the relative handover candidate base stations from the RTD estimation table (ideally maintained in the BSC database) to prepare a list of adjacent units (eg In the IS-95 system, the "adjacent group" at step 106, the source BS uses the scrambling code and RTD estimation in the "adjacent list message" to broadcast the neighbor unit list or Transmission to included mobile stations ° In fact, the BSC will keep track of the estimated rtDs transmitted to the mobile stations' so as not to duplicate the RTD information already available on the mobile stations. At this point, the mobile stations have now received synchronised Base station list (and quality information to be reported). Adjacent messages received also include uncertain estimates (described in more detail below r ')) < the mobile station will store neighboring units in local memory At the step (timing), the signal peak of the selected unit using the combined wave signal may match, and the base neighboring unit moves to step 108. 'Along with the previous neighboring units currently owned, the estimated information is ^ And along with other relative Adjacent cell information, the mobile station can ^ traditionally match the filter configuration and start the main cell search. The mobile station using the main cell search of the mobile device will generate a base ^ peak, which will enable the mobile station to obtain sufficient quality to obtain the delivery : In step 1110, the radio station uses the generated waveband-compliant value to form an interrelation with the RTD estimate to determine that the peak is the scramble code most closely associated with the adjacent unit (step 112). In the correlation generated in step 114 and step 112, the mobile station can select the scrambling code of the most likely handover candidate unit from the phase = and then start the unit search (step 1 丨 6 >. Discard

The wave generator turns out the signal peak. In this hypothetical case, the scrambling code correlation procedures (e.g., 'step 1 12') can be omitted entirely. However, in any event, according to the invention, the mobile station uses the estimation to determine the most likely handover candidate unit from the list of neighboring units to enable the mobile station to ignore the apparent compliance peaks of the filter, and / or combine compliance scrambling Some peaks of the code significantly reduce the complexity of the unit search process and substantially increase the search speed. By using the above-mentioned inventive method, as the mobile station connected to the base station assists', each base station (cell) has a relative time difference associated with the neighboring base station (cell). For some reason, if there is no mobile station connected to a particular base station, the RTD estimation table for that base station will not be updated. As a result, since the relative timing between adjacent base stations will continue to change, the uncertainty (or inconsistency) of the RTD estimation table registration for this base station will increase. In general, the uncertainty of the RTD estimation will increase over time, and once the update is completed (for example, based on the RTD report received from the mobile station), this uncertainty is typically minimal immediately. As a result, in order to keep the mobile station inactive (for example, a private indoor system at night, or during holidays), and to have a more robust communication system as previously described, the RTD uncertainty estimate can be obtained from the base station along with the adjacent The RTD in the manifest message is estimated to be broadcast or transmitted. For example, the mobile station can then set (e.g., increase) its time search window based on the amount of additional uncertainty allowed. The mobile station is thus able to handle base stations with a relative uncertainty knowledge of its RTDs, and it can also reduce its complexity when providing estimates for certain RTDs. An additional method to further reduce the occurrence of non-deterministic problems when there are fewer active stations for a relatively long period of time is to fix the whole system in a fixed position.

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V. Description of the invention (13) The "virtual" mobile station is placed on top. The function is "and can be called by relatively high stations" to provide more mobile stations so that they can be located at the edge of mobile stations. Arrive "These" virtual mobile stations have limited deterministic RTD estimation table registration of the RTD update "such" virtual "line by a plurality of base stations (for example, close to a single figure 2 is according to the age society of the present invention μ f π ># π t μ # & Simplified block circuit diagram of 200 examples of the mobile communication system of the preferred embodiment, which can be used to realize the promotion of the base station timing (the two phases (the phase / time difference) and the power increase. Unit Search speed method (figure). System 2GG is ideally an asynchronous CMA mobile communication system, including three base stations and three mobile stations for illustration. However, it should be understood that the displayed base stations The number of mobile stations is used for illustration, and the typical system includes more than three base stations and three mobile stations. For this example, the 5 'MS 1 is operating in active mode and is connected via a communication interface. While connected to BS1. According to step 10 of method 100 (Figure 丨), MS1 has received adjacent inventory information, which ideally includes relative RTD estimates, but can optionally combine information from BSC 2 04 'Connecting' to the MSI is possible via the uncertainty estimate on the BS1) dedicated control channel. At least two adjacent (units) listed as entries in the RTD estimation table are Torque 2 and BS3 ^ on a periodic basis

On the basis (or on request), the MSI will monitor and report the quality (signal strength, SIR, signal-to-noise ratio, or SNR, bit error rate, or BER, etc.) of these base stations to BSC 204 (via BS1) . Now that MSI has received the RTD estimate from BSC 204 (via BS1), when MSI searches for BS2 and BS3, MSI can use BS2 and BS3 to synchronize itself relatively quickly at least during the first occasion. When MSI is synchronized with BS2 (or BS3), it can assume that MSI has a base

Page 20 219 ^ ·

V. Description of the invention (14) "Good 11 RTD estimation of the platform. On a periodic basis or on demand, MSI can report the estimated signal quality of these at least one registration in the adjacent unit list to the BSC 204 (via BS1). In addition to the quality estimate, MSI can also report the current RTD estimate to BSC 204. The unit search condition of MS2 is similar to MSI. Except for the example shown, MS2 is included with BS1 and BS2. In the SOHO, there is only one other base station (for example, BS3 connected to 214 via the broadcast interface). For this example, the MS3 is operating in idle mode (no connection setting), but it can still be considered according to MS3 & quot The best one is a list of adjacent units received on the broadcast channel of the base station and still be able to supervise the base station (for example, in this case, BS3 connected to 218 via the propagation interface). Similarly, MS3 can also supervise BS1 ( Link 2 08) and BS2 (link 212 through the broadcast interface). Furthermore, BS3's RTD estimate broadcast can help MS3 to synchronize with BS1 and BS2 more quickly, or at least the first synchronization process takes place. The complexity of the search can be reduced, and the speed of the unit search can be significantly increased. Ideally, each mobile station operating in the mobile communication system 200 will have its RTD measured on a periodic basis or on demand. Estimates are transmitted to BSC 204 (via BS1) »BSC 204 stores the RTD estimates received from the mobile station in the RTD estimation table. Or 'in the RTD estimation table (that is, the estimated difference between a pair of base stations) Each stored entry is calculated based on the estimates received from a plurality of different mobile stations. #N, can be used to form a previous X received estimate, or the value updated in the table from flat 2 to y minutes ago can be borrowed. Recalculate special estimate implementations by updating previous estimates or base's received tributes. Stored in table

Page 21 V. Description of the invention (15) will then be transmitted to other mobile stations along with the list of adjacent units as described above to help these mobile stations synchronize with neighboring base stations. In addition, thanks to the technology in the art, the RTD estimation table need not be stored in BSC 204; ideally 'the table can be stored in fact on the network (for example, in a register with MSc or in a separate Database). In another aspect of the invention, the RTD estimates can be used to determine the location of the mobile station. However, the 'location calculation needs more accurate RTD estimation than the case of unit search. This is because the concept of mobile positioning essentially relies on the propagation delay decision between the mobile station and each of the plurality of base stations, or TOA or TDOA measurements in various different base stations. In most cases, the search speed of the unit V) can be significantly improved 'without describing the transfer delay. Therefore, when measured by one or more mobile stations, it is usually sufficient to make an estimate based on the time difference between the two base stations without having to consider the delay effect of the downlink signal received by each of these base stations. . On the other hand, to perform mobile positioning, a more accurate estimation of RTD is needed. The present invention solves this problem by calculating an improved RTD, which describes the propagation delay signals of the uplink and the downlink. In essence, the difference between the time when the first base station starts transmitting its downlink signal and the time when the second base station starts transmitting its downlink signal. This improved RTD estimate can be calculated by using: (1) Local reception and transmission time of the uplink and downlink signals at the base station, when measured at each of these relative base stations, and (2) the TOA difference on the downlink signals from the base station As the report of the mobile station. The changed RTD information can then be used by other mobile stations for positioning.

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In a preferred embodiment, the modified RTD estimate is stored in a database table on bsc or. Subsequently, the location decision of the second mobile station needs to be △ on a general basis, triggered by certain events, or explicitly requested by bsc or action two) ° The second mobile station is based on the downlink from each base station No. 2 mobile station receives time to measure the time difference between the base stations, and reports the measured time difference to Bsc. The BSC then compares the improved RTD estimate that was saved between the particular pair of base stations with the time difference measured between the same pair of base stations as a mobile station report. Based on this comparison, the propagation delay between several of these base stations and the mobile station can be calculated and the correct decision of the position of the mobile station can be performed. Furthermore, TOA or TDOA measurements can also be used to determine location. However, regardless of the niches used, positioning calculations are inherently dependent on what is present in the action environment, usually even if three occur. Substantial promise. That is, whatever action the mobile station performs as desired, each RTD determined by the mobile station is estimated to include only two base stations, ie, S0H0 (that is, soh including three different base stations). By repeating the RTD decision during multiple different SOHO procedures, the improved estimated RTD between multiple possible pairs of base stations can determine the improved RTD estimate at positive f and then be calculated by other mobile stations (also evaluated (Does not include the mobile station), Fantawild set other locations. However, it is attributed that the station position included in the estimated RTD calculation can also be determined by using the improved RTD estimation. Any positioning procedure is ideally used as much as possible with the base station. The accuracy of estimating the ef position is improved. Referring to FIG. 3, it shows the power of the mobile station at or about to enter S0H0.

42 1 94 Ί "ϋ 发明 Description of the invention (π) road map. The first base station BS 1 will transmit the downlink account number 3 02 (pilot data frame or routing data frame) data frame at time Ttl, such as the measurement in the base station 1 time base. The uplink signal 300 from the mobile station MS1 is 3 by the first base, and the station BS1 is received at time Tr1, and is also measured on the time base of the first base station BS1. Similarly, the second base station BS2 will transmit the downlink signal 306 at time Tt2, and receive the uplink signal 304 from the mobile station MS1 at time Tn, and measure it on the time base of the second base station BS2. Usually, the time base of the two base stations in an asynchronous network has a relative time difference Δ. In other words, if an event (such as the transmission of a pilot data frame) occurs at time T1 of the first base station BS1, the relative event will occur at the following time (4) T2 = Τ! + Δ (ί) second base Occurs on station BS2. Once the RTD Δ is known, it can be used by other mobile stations for mobile station positioning. In addition, each downlink signal has a cutoff, which is related to the pass time of the pilot channel data frame. Therefore, the routing information from the first base station BS1 is transmitted at the following time Ίη = \ ι ^^ ι, (2)

Among them, Tρ1 is the transmission time of the pilot channel data frame from the first base station] bS1. Similarly, the routing channel data of the downlink signal from BS2 will be transmitted at the following time Q

Tt2 = Tp2 + t2 (3) When 30110 is activated, the mobile station 1 ^; 1 will monitor the pilot, and 1; 2 = 〇6 after the sheath 'When the mobile station MSI is in SOHO, the second base station BS2 Will transmit data, and the cut-off time h of the signal will be adjusted, so from the first base

Page 24 V. Description of the invention (18) The data of the base station BS1 and the second base station BS2 will arrive at the mobile station at about the same time. In the following discussion, 'general energy conservation is considered, where it is assumed that the cut-off time and% are known. This scenario covers two cases of soho activation and setting of SOflfO. That is, referring to FIG. 4 ′, it is a description of related timing diagrams of various S0H0 signals transmitted and received in the system of FIG. 3. All times in the figure are described in general arbitrary time base. However, for the purpose of performing RTD calculations in accordance with the present invention, 'the time of each event is reported in the local time base of the signal station (i.e., the' mobile station or base station) incorporating the event. At time Ttl ', as measured in the first base station time base, the pilot or routing data frame 402 is transmitted by the first base station BS1. Data frame 40 is received at mobile station MS 1 at time Tnrl, and time I " is measured in the time base of mobile station 1. After the transmission time, time U is delayed by the transmission time delay time τm, and the transmission delay time is the time required for the signal to pass from the first 1 to the mobile station MS1, and vice versa. Mobile station a transmits an uplink signal 404 at time 1. For simplification without taking a single application, it is assumed that the mobile station MSI is transmitted at the same time, and the uplink signal 404, it will receive the downlink signal 402 from the first base station BS1. Therefore, ^ — Tnt = Tnrl, and (4) 〇 uplink line number 404 is received on the first base station BS1 at the following time — Trl = Ttl + 2 r! (5) Ground ^ B: 2 mobile docking station: The uplink signal S04 of S1 is received at the second base station BS2 at time Tr2, and after transmission time l, its delay will be transmitted. Page 25

O: \ 56 \ 56974.PTD

The second base station BS2 also prepares 406 at time Tt2. After the transmission delay time ^, ^ line ^ or pilot data room Tmr2 is received by mobile station MS1m. When the road number 404 will calculate the RTD △ at that time, the mobile station MS1 will report the time difference between the reception time U of the line signal 4.6 and the mobile station: the second station = the transmission time of the line signal 404 ^ ^. Because of tdifi = 1 ^ and 2 (

= Ϊί 2 In Figure 4, the time L㈣ is relatively large, and it is typically tied to the plot that is not the best. Uplink of the second base station BS2 Using the above concept, we can then generate the following expression at the time Trs of the second line signal

Tr2 = 2 r2 + tdiff + Tt2 (7) Finally, we can produce the following expression of tdiff: ^ tdiff = TtI -Tt2 + r j-r2 + Δ »(8)

This formula is obtained by subtracting the downlink time from the second base station BS2 (the pilot data frame on the soho start or the routing data during the SOHO) from the transmission time Tmt of the uplink signal 404 from the mobile station MSI. The arrival time l ·, 2 of the line signal 406 is obtained and all are measured in the time base of the second base station BS2. Therefore, it can be understood from the well-known techniques in the art that the time base at the second base station is as follows:

Tmr2 = Tt2-t2, and (9)

Tfflt = Ttl + A + (10) There are three equations: (5), (7), and (8). And the three unknowns are: 1)

4S1941 on page 26 ^ Description of the invention (20) the transmission delay time BS1 between the mobile station MSI and the first base station BS1; 2) the transmission delay time BS2 between the mobile station and the second base station bs2; and 3) The time difference Δ between the first base station BS1 and the second base station BS2 is Δ. It is easy to solve △, and Δ-1 / 2 (tdiff-Ttl-Trl + Tt2 + Tr2) * (11) This formula is a solution that provides the intended RTI) △ between these base stations BS1 and BS2. According to a preferred embodiment of the present invention, the mobile station MS1 will report the time difference tdiff ', and each of these base stations BS1 * BS2 will report their relative network transmission and reception time ^ RTD △ calculation will then be performed in Bsc or Msc Go to line 0. In the selection, once the required timing data is provided, the calculation can be performed in the mobile station MSI or the base station "> By calculating the improved RTD estimate between the base stations through various different types of asynchronous mobile communication systems' Uplink resolution or downlink resolution can be used to determine the location of the mobile station in the system without absolute time reference. For example, Fig. 5 is a flow chart describing a possible method 500 for facilitating the timing of a base station, and a selected mobile station position in an asynchronous mobile communication system is determined according to a specific embodiment of the present invention. Thanks to the usual techniques in the art, according to the present invention, many other positioning methods such as TOA 4TDOA can be used in conjunction with improved RTD estimation to facilitate positioning. At step j 504 ′, the BSC calculates a complex modified RTJ) estimate between various pairs of base stations, which are controlled by the BSC or base stations listed in the neighbor cell list. This calculation is performed using data provided by other mobile stations used in the mobile communication system. Therefore, the effect of delay

V. Description of the invention (21)-It is considered that the R T D estimate can be calculated with a high degree of positive pain. Ideally, the tables for these modified RTD multipliers are maintained in the BSC database. In step 506, the selected mobile station monitors the base stations in adjacent cells. For the purposes of the current positioning method 500, 'this system includes, for example, monitoring of known sequences transmitted periodically by the base station. This monitoring procedure may include regular monitoring of base stations by potential delivery candidates. It should be noted that the known sequence supervision from the base station can often be performed even with limited monitoring to prevent the base station s 0 Η 0. In step 508, the mobile station measures the TOA of the downlink signals transmitted by several different base stations. Each TOA measurement can be measured at the time base of the mobile station 'or as a value for the source base station or some other base station. The TOA measurement is temporarily stored in the area memory along with information identifying a base station that matches each TOA measurement. This information is then sent to BSC for further processing. The measurement in step 508 may be performed on the pilot channel data or the routing channel data. Because base stations usually " know " the cut-off time, even when using a routing channel, the time difference between such base stations (that is, the time difference between the transmission of the pilot data frame of the base station) is known . In step 5, the BSC adjusts the TOA measurement by adding the rtD estimates to the TOA measurement to explain the ^! ^ Β between various base stations. In step 512, it is calculated by using the adjusted TOA measurement. The transmission delay time of each downlink signal is, and step 514 uses the calculated transmission delay time to estimate the position of the mobile station. For example, the positioning information can then be transmitted to the mobile station, stored in the BSC, or transmitted to the home position register (HLR). ^ In another specific embodiment, the calculation of steps 510, 512, and 514 can also be performed in action. Station, MSC, or some other location in the network.

O: \ 56 \ 56974-PTD Page 28 421941 V. One implementation of TOA of invention description (22) The uplink is transmitted in step 508 of the platform. These entire steps of the OA measurement method 500 are described in the method 500 described in FIG. 5 to provide a positioning estimate based on measurements performed on the mobile station on the downlink. In the example, the mobile station positioning system uses two The uplink signal is determined. The solution is essentially the same as the downlink solution, except that instead of TOA which measures the uplink signal, TOA measurement is performed on the multi-baseline signal, and the uplink signal is provided by the mobile station uplink signal and then provided to the BSC or MSC, and the adjusted volume and delivery delay time will be calculated as follows: Line solutions 510 and 512 »Together with the standard RTD estimation discussed above, if the rtd estimation table of the special base station is not updated, Certainty also increases over time. However, for localization purposes, the accuracy required for RTD estimation is greater than that of the unit search. Therefore, the estimated improved RTD obtained during SOC should be up-to-date, so the clocks in the base station will not drift compared to each other. Otherwise, it will not be easy to perform correct action positioning decisions if possible. Many of the same methods described above to describe the uncertainty problem in standard KTD estimation can be used in improving R τ1) Estimating the similarity described in this article. The method of knowing improved RTD estimation can also be used to further improve Together with the unit search procedure described in Figures 1 and 2. In a preferred embodiment of the cell search method 100 (reference circle.) 'The time difference reported by the mobile station in SOHO is directly used to calculate the RTD estimate; no information from the base station is needed. Therefore' Please refer to FIG. 4 again. The standard RTD estimation is equivalent to subtracting from the mobile station receiving time of the downlink signal from the second base station BS2.

Page 29 5. Description of the invention (23) The mobile station receiving time τ ^ ^ of the downlink signal from the first base station BS1 is shown in FIG. 4 ′ This value is described by the time difference tdiff. The direct use of the time difference reported by the mobile station provides a significant improvement over the previous unit search, and in most cases' significantly reduces the complexity of the unit search process to overcome problems found in other potential location methods. However, if greater accuracy is needed, the timing uncertainty of the SOHO searched mobile station can be further reduced by 50% by using an improved RTD estimate, which takes delivery delay into account. By using improved estimates 'the time delay that the mobile station must search during the cell search process is considerably reduced', especially when compared to the cell search method of the prior art (when the cell search uncertainty interval is then determined The size of the unit and the number of unit divisions. For example, in previous unit's improved estimation results with a unit radius of about 30 km in an even non-divided unit system, the uncertainty is less than 300 microseconds, assuming rows The position of the moving platform can be estimated within a radius of 3 units. In contrast, the normal search window of the search method is about 丨 0 microseconds. Therefore, the use of RTD can provide improved second-order smaller units or In a cell-based system that divides the unit, it is even better to estimate the search movement between the target base station and the execution unit: the back and forth delay, but it may also reduce the uncertainty of the unit search :: ”In the case of the division order 7L. When executed For RTD calculations, such as the position of the eighth round, the estimated round-trip delay can be easily changed from the previous one and the detailed description. Described in 'understanding of particular embodiments but Pat ^ j circle in the base station attachment disclosed. For example, according to the present invention is non-limited

aim page 30

42 1 94.1

Page 31

Claims (1)

4.1 J 26. Scope of Patent Application 1. A method for non-simultaneous application, which includes transmitting the difference to the plural of the difference; and the mobile station 2. If the application is dedicated to the output base 3. If the action Channel transmission delay. 4. If the system includes the specific signal; If the filter is included 5. If the base is based 6. If the mobile station signal is completed in the phase application and the latest application is required, please specialize The application for a round of letters should be decided to apply for a special mobile station. At least one of the receiving areas should be reduced by one base to reduce the mutual benefit area to reduce the profit area. Mobile communications & ^ ^ The system facilitates multiple base stations to set the following Step: At least one of the meanings is to compare at least one estimate with respect to the at least one estimate. 4 The pair of base stations and the relative time difference between i are the estimated time included between neighboring base stations = at least one estimated relative time. Difference. The method of item 1 further includes the following steps ^ an estimation of the relative time difference and matching filtering (, series; and the results of the steps to start the unit search. The method of item 2 further includes estimating the Step of the inter-delay delay, the uncertainty of the estimate in the correlation step. The method of item 2, wherein the correlation step is one less estimated relative time difference and the coincident filter output is less one estimated relative time difference. Whether the value may meet the method of item 4 of the peak value β range of interest, wherein the starting step is the result of the step of selecting the scrambling code. The method of item 1 of the range of interest, in which the mobile communication system ϋ Page 32 421941 —β VI. Patent Application Scope It includes non-synchronous direct sequence code division multi-directional proximity system. 7. The method according to item 1 of the patent application scope, wherein the transmitting step includes the at least one estimated relative time difference broadcast or transmitted in the adjacent list message. 8. The method according to item 7 of the patent application, wherein the neighbor list message includes at least one scrambling code combined with the neighbor base station. 9. The method of claim 1, wherein the transmitting step includes transmitting an uncertainty value combined with the at least one estimated relative time difference. 1 0. The method according to item 1 of the patent application range, wherein the mobile station transmits the at least one estimated relative time difference together with the quality of the adjacent units of the at least one base station which are reported to the plurality. 11. The method of claim 10 in the scope of patent application, wherein the base station controller combining at least one of the plurality of base stations stores the at least one estimated relative time difference in a database. 1 2. The method according to item 1 of the scope of patent application, further comprising the step of determining the approximate position of the mobile station by using the at least one relative time difference 1 3. The method according to item 12 of the scope of patent application, wherein The step of determining the approximate position includes the following steps: Calculating the reception time of the first downlink signal transmitted by the at least one of the plurality of base stations and the second downlink signal transmitted by the adjacent base station. Time difference between mobile stations; and comparing the at least one relative time difference with the calculated time difference to determine a difference between the at least one of the plurality of base stations and the neighboring base station Page 33 94- 1 VI. Scope of Patent Application-** ------ At least one possible location of the mobile station in question. 14. Gan > «· A system for synchronizing multiple base stations in a mobile communication system, which includes: / T The first base station of the plural base station-flute-Health Secret Fighter 4, the first base station A base station is used to broadcast or transmit at least one Shi 4 + Gu # 4. Η Shi Tu Lan Lan Ma β A Α estimated 50 relative time difference, the at least one estimated relative time difference is included in the 篦- Mountain A time difference; and the estimated action σ between the base station and the neighboring base station is used to receive the at least one estimated relative time difference. Generate ^ link / ^ η 1 The relative time difference is associated with the corresponding filter output signal, and the cell search is started. 1 6. The system according to the scope of application for patent] q hundred ^^ δi item, wherein the time difference between the operating phase β βA β t of the mobile station and the output signal of the coincident filter are compared, and it is determined that at least- Officials, please * waisuishan A. Estimate whether the 30-day relative time difference is relative to the peak value of the anxiety wave Is output signal. 17. The system of the 15th box in the patent scope of the application, such as the golden gold μ, is used in the system of the items $, 丨, ^ ^, where the mobile station is the operation number peak # violate M g MU τ relative time difference and compliance The scrambled chirp is selected based on the correlation of the output signal value of the filter. 18, if the patent application scope No. 14 system includes non-synchronous DS_CDMA system β ,, this impresses the communication system 1 9. if the patent application scope No. j 4 system operates in broadcasting or transmission in adjacent Qing, ',, China The first base station time difference. The at least one estimate with the morning message on the next day is relatively 421 9 ^ 1; 6. Scope of patent application Where the relative time difference between the first base station and the time difference is 20. The system of item 4 in the scope of patent application is further operated to transmit a certainty value in combination with the at least one estimate. The system is sent to the system of item No. 14 in the patent scope, wherein the mobile station transmits the relative time difference of the ancient plan, together with the transmission report to the adjacent crying quality of the first base. The system of item 14 in the scope of patent application of Λ2'Λ, wherein the at least one estimated relative time difference is stored within the thickness of the base station controller in combination with the first base. 23. The system of item 14 of the scope of patent application further includes a processor for determining the approximate position of the mobile station by making i = i V an estimated relative time difference. For example, the system of item 23 in the patent application park, wherein the processor compares the estimated relative time difference between I-Xi and the time difference I measured by the mobile station to determine the time difference between the first base station and the camera. Neighboring base station at least one possible location for throbbing. 2 5—Sitian, * A mile method for estimating the relative timing of a plurality of base stations in a non-synchronous mobile communication system, which includes the following steps: Transmitted by the station_ the first downlink signal and one of the first downlink signals transmitted by the second base stations; ^ by using the first downlink signal and the second downlink signal: at the first base station The estimated relative time difference between the base and the second base station time base. Page 35 421 94-1 26. The method of claim 25, wherein the first action a is in the delivery state. D 27. The method according to item 25 of the patent application scope further includes the step of calculating the difference stored in the phase time difference table. 28. The method of claim 25 in the patent application scope, further comprising: / will be from the first mobile station and the second base station; and • • by using the first and second base stations A on the uplink signal = Receiving time, the first downlink signal and the second downlink signal, the transmission time, and the time difference between the reception time of the second downlink signal and the transmission time of the uplink signal on the first mobile station. The estimated relative time: time difference, in which the reception time of the uplink signal and the transmission time of the second downlink signal are within the relative base time base of the transmission or reception. 'The calculation indicates that the first action Delay between the station and the first and second base stations. 29. The method according to item 28 of the patent application, further comprising the step of at least one possible location of the second action Λ station with the downlink signal transmitted by the second station. Guimu decides the second action 3 0. If the method of the scope of patent application No. 28 is applied, the uplink signal transmitted by the second mobile station is used ^ by making the receiving time on the second base station and by Let 哕 ^ land station and determine at least one possible position of the second mobile station = sudden. Time difference Page 36 i 34 VI. Scope of Patent Application 3 1. The method according to item 28 of the scope of patent application, wherein the estimated relative time difference is used to synchronize the first and second base stations. 3 2. The method according to item 25 of the Shen Hong patent red circle, wherein the step of calculating the estimated relative time difference further includes the step of explaining the delay of the transmission of the first downlink signal and the second downlink signal. 3 'The method according to item 32 of the scope of patent application, further comprising the step of transmitting the estimated relative time difference to the second mobile station. 34. The method according to item 33 of the scope of patent application, the steps include the following steps: the second mobile station correlates the estimated relative time difference value with a matching filter / rollout signal; and based on the result of the step of generating the correlation Start unit search. 35. The method according to item 33 of the patent application park, further comprising the following steps: based on the approximate location of the second mobile station, estimating the signal transmitted between the second mobile station and the first base station and the second mobile station The transmission delay of the signal transmitted between the base station and the second base station; adjusting the estimated relative time difference by the estimated transmission delay factor to determine the local estimated relative time difference on the mobile station; the second mobile station makes The local estimated relative time value is correlated with the corresponding waver output signal; and a unit search is started based on the result of the correlation generation step. 36. The method as claimed in claim 25, further comprising determining at least one of the second mobile station and the first and second base stations by determining 6. Apply for at least one of the estimated base stations by reading the distance between patents; ten: Calculate the time difference with the first and second positions. At least one possible position of the second mobile station with n Gu She Ji Yi 37. If the patent application Fan Yuan term is used in plural different base pairs, the method further includes the step of calculating the second set by making the mobile station and the plural base stations: :: =: time J. And determine the first mobile station 38, a method to promote timing between asynchronous stations, and see ^; the mobile station and the base of the network receive from a plurality of mobile stations; ::: column Steps: The relative time difference data transmission of each mobile station includes: time difference data 'from the time base of each of at least two base stations. The measurements by the mobile stations are based on the received relative time difference meter, and the estimated time difference between the materials is expressed as The time difference estimate in the 'Small Set Relative Time Difference Estimate' is stored between the time bases of the two base stations. The relative time difference estimate is stored in the relative time gate and the relative time difference estimate is transmitted to the receiving bank. For the 38-item method, the information in the list is transmitted with the estimated relative time difference. Neighboring unit 40. The method according to item 38 of the patent application, wherein the relative time difference estimation of the transmitting station is used to assist the synchronization of the receiving and receiving stations. Ordering station and base 4 1. According to the method in the 38th scope of the patent application, #Estimation includes the measurement time received from one of the plural mobile stations ~ the relative time difference 1 circle page 38 6. The scope of patent application is poor. 4 2. The method according to item 38 of the scope of patent application, wherein the relative time difference estimation is determined by calculating a relative time difference estimation value from a plurality of measurement differences received from a plurality of mobile stations. 43. The method of claim 38, wherein the step of determining the relative time difference estimation further includes a step of transmitting a delay between the mobile station and at least two base stations measuring the time base difference. 44. The method of claim 43 in which the relative time difference estimate transmitted to the receiving mobile station is used to estimate the position of the receiving mobile station. 45. The method of claim 38, further comprising the steps of: estimating an error range of the relative time difference estimate; and transmitting the error range to the receiving mobile station. 4 6 · —Asynchronous mobile telex video system, including: a plurality of base stations, which are used to transmit data to the plurality of mobile stations, and receive data from the plurality of mobile stations, the plurality of base stations are individually received Relative time difference data, and the relative time difference data from each mobile station includes: the measured difference between the time bases of two of the base stations measured by the mobile station; a temporary register for storing relative Time difference table, each of these entries in the table contains a relative time difference estimate calculated from the relative time difference data; and Page 39 Λ 2.194-1 VI. Scope of patent application Among them, the first of the plurality of base stations transmits the relative time difference estimate to the receiving mobile station to promote communication between the mobile station and the second base station. timing. 47. The system of claim 46, wherein the register further stores a list of adjacent units. 48. The system of item 46 of the scope of patent application is deducted, wherein the register further stores the error data of each relative time difference estimation. Page 40