Title of Invention

A MECHANICAL SEAL ASSEMBLY

Abstract A method for conducting pilot signal search in a wireless communications system, comprising determining a location of a mobile station within said wireless communications system determining a plurality of search window sizes corresponding to a plurality of pilot signals based on said location of transmitting sources of said plurality of pilot signals.
Full Text METHOD AND APPARATUS FOR REDUCING PILOT SEARCH TIMES UTILIZING MOBILE STATION LOCATION INFORMATION
BACKGROUND OF THE INVENTION
I. Field Of the Invention
The present invention relates to communications. More particularly, the invention concerns a method ar:d amaxarus for reducing search times associated with the handoff of a call from one base station to another base station.
II. Description of the Background Art
Wireless communication systems generally comprise, amongst other elements, a wireless unit, commonly referred to as a mobile telephone (mobile), that communicates with one or more base stations when making a call. The mobile communicates with the base stations on one or more channels that are contained within a frequency band assigned to the mobile by a base station controller. A communication from the mobile to a base station is made on what is called the "reverse link," and a commnication from the base station to the mobile station is made on the "forward link." During a call, the mobile station is constantly searching for other base stations that the mobile might need to continue the call while the mobile station is moving around.
One important element of a mobile used in such a wireless system is the searcher. The searcher is programmed to search for pilot signals (pilots)

transmitted trom different bases stations in at least three cases: 1) when a mobile is trying to acquire a base station for communication; 2) in the idle state when the mobile is on the paging or access channels; and 3) in the traffic state where the mobile is in control of the traffic channel. The speed of searching the pilots on the frequency assigned to the mobile and other frequencies determines the search performance of the mobile. In slotted mode, the objective is to search all pilots in the neighi»or set before the slot expires. Slotted mode refers to an operation mode of the mobile where the mobile monitors only during selected slots of time. Also, when searching pilots in a "candidate" frequency, the mobile needs to complete its search of all pilots in the candidate set as quickly as possible so that is tunes back to the serving frequency and minimizes the voice degradation caused by searching the candidate frequency. As discussed below, the candidate frequency is a potential handoff frequency, and these searching techniques are used to coordinate handoffs of communications in the wireless communication system.
A. Handoffs
A mobile used in a code-division-multiple-access (CDMA) wireless system supports three types of handoff procedures when the mobile is in control of the traffic channel. The use of CDMA techniques in a multiple access communication system is disclosed in U.S. Patent No. 4,901,307, issued February 13, 1990 and entitled "SPREAD SPECTRUM MULTIPLE ACCESS COMMUNICATION SYSTEM USING SATELLITE OR TERRESTRL^L REPEATERS," assigned to the assignee of the present invention and incorporated by reference herein. The three types of handoffs are:

1. Soft Handoff - A handoff in which the mobile commences communications with a new base station without interrupting communications with the old base station. Soft handoff can only be used between CDMA, channels having identical frequency assignments.
2. CDMA to CDMA Hard Handoff - A handoff in which the mobile is transitioned between disjoint sets of base stations, different band classes, different frequency assignments, or different frame offsets.
3. CDMA to Analog Handoff - A handoff in which the mobile is directed from a cdma forward traffic channel to an analog voice channel.
To perform soft handoff, the mobile continuously searches for assigned sets of pilots. The term "pilot" refers to a pOot channel identified by a pilot sequence offset and a frequency assignment. A pilot is associated with the forward link traffic channels in the same forward link CDMA channel, or similarly with the reverse link on systems using reverse link pUots.. All pOots in a pilot set have the sanne CDMA frequency assignment. For clarity, pilots are discussed in terms of the forward link only.
The mobile searches for pilots on the current CDMA frequency assignment to detect the presence of CDMA channels and to measure their signal strength. When the mobile detects a pilot of sufficient strength that is not associated with any of the forward link traffic channels already assigned to it, it sends a pilot strength measurement message to the base station with which it is

currently communicating. The base station can then assign a forward link traffic channel associated with that pilot to the mobile and direct the mobile to perform a handoff.
The pilot search parameters and the rules for pilot strength measurement message transmission are expressed in terms of the following sets of pilots:
• Active Set The pilots associated with the Forward Link
Traffic Channels assigned to the mobile.
• Candidate Sen Tne pilots that are not currently in the Active Set
but have been received by the mobile with sufficient strength to indicate that the associated Forward Link Traffic Channels could be successfully demodulated.
• Neighbor Set Tne pilots that are not currently in the Active Set
or the Candidate Set and are likely candidates for handoff.
• Remaining Set Tne set of all possible pilots in the current system
on the current CDMA frequency assignment, excluding the pilots in the Neighbor Set, the Candidate Set, and the Active Set. This set of possible pilots consists of pilots whose pilot FN sequence offset indices are integer multiples of some pilot increment.

The base station may direct the mobile to search for pilots on a different CDMA frequency to detect the presence of CDMA channels and to measure their strengths. The mobile reports the results of the search to the base station. Depending upon the pilot strength measurements, the base station can direct the mobile to perform an inter-frequency hard handoff.
The pilot search parameters are expressed in terms of the following sets of pilots:
• Candidate Frequency" Neighbor Set: A list of pilots on the CDMA Candidate Frequency.
• Candidate Frequency Search Set: A subset of the Candidate Frequency Neighbor Set that the base station may direct the mobile to search.
B. Pilot Search
In current systems, the base station sets the search window, that is, the range of PN offsets, in which the mobile is to search for usable multipath components. These multipath components are used by the mobile for demodulation of an associated forward link traffic channel. Search performance criteria, and general wireless system criteria, are defined in standards T[A/EIA-95x and TLA/EIA-98-B, all issued by the Telecommunications Industry Association, and ANSI J-STD-018, issued by the American National Standards Institute, all of which are incorporated by reference herein. These searches are generally governed by the following:

• Active Set and Candidate Set The search procedures for pilots in
the active and candidate sets are identical. Tne search window size for each pilot in the active and candidate sets is the number of PN chips spedfied in Table 1 corresponding to SRCH_WIN_A. For example, SRCH_WIN_A5=6 corresponds to a 28 PN chip search window or ±14 PN chips aroimd the search window center. The mobile station centers the search window for each pilot of the active and candidate sets aroiind the earliest arriving usable multipath component of the pilot.
Table 1

SRCH_W1N_A SRCH_WIN_N
SRCH_WIN_NGHB R SRCH_WIN_R
CF_SRCH_WIN_N Window Size (PN Chips) SRCH_WIN_A SRCH_WIN_N
5RCH_WIN_NGHB RSRCH_WIN_R
CF_SRCH_WIN_N Window Size (PN Chips)
0 4 8 60
1 6 9 80
2 8 10 100
3 10 11 130
4 14 12 160
5 20 13 226
6 28 14 320
7 40 15 452
Neighbor Set If a flag for a different neighbor search
window is set, the search window size for each pilot in the neighbor set is the number of PN chips specified in Table 1, corresponding to search window size parameter associated with

the pilot being searched. If the flag is not set, the search window size for each pilot in the neighbor set is the same and is equal to the number of PN chips specified in Table 1 corresponding to SRCH_WIN_N. Tne mobile centers the search window for each pilot in the neighbor set around the pilot"s FN sequence offset, using timing defined by the mobile"s time reference.
• Remaining Set; The search window size for each pilot in the remaining set is the number of PN chips specified in Table 1 corresponding to SRCH.WIN.R^. The mobile centers the search window for each pilot in the remaining set around the pilot"s PN sequence offset, using timing defined by the mobile"s time reference. The mobile searches for remaining set pilots whose pilot PN sequence offset indices are equal to integer multiples of the pilot increment
• Candidate Frequency Search Set: If the flag for candidate frequency is set, the search window size for each pilot in the candidate frequency search shall be the number of FN chips specified in Table 1, corresponding to SRCH_WIN_NGHBR associated with the pilot being searched. If the flag is not set, the search window size for each pilot in the candidate frequency search set shall be the number of PN chips specified in Table 1 corresponding to CF_SRCH_WIN_N. The mobile centers the

search window for each pilot in the Candidate Frequenc}^ Search Set around the pilot"s PN sequence offset using, timing defined by the mobile"s time reference.
C. Time to Search
Each phone manufacrorer has its own way of implementing a search strategy. In all strategies, the time to search a specific pilot depends on the window size and the hardware of the searcher. Given certain hardware, the time to search a pilot is linearly proportional to the search window size. Reducing the search window size will result in a substantial reduction in searching time. Using current searching procedures, the window sizes are mostly determined by the size of the coverage area of a given cell. A cell is the geographical area covered by a base station for communication with a mobile. Four such cells are shown in Figiire 1. Regardless of the location of the mobile in the serving cell, current search windows are sized to correspond to the worst case scenarios. That is, they are sized to correspond to a mobile located at the greatest distance from the base station but within the cell.
On the paging or traffic channels, the mobile centers its search window for each pilot in the neighbor set around the pilot"s PN sequence offset, using timing established by the mobile"s time reference. The mobile"s time reference is defined as the earliest arrived and usable path. The worst case scenario determines the search window size. For example. Figure 1 shows four adjacent cells 102, 104, 106, and 108 in a wireless system 100, each having a pilot

designated PNl, PN2, PN3, and PN4, respectively. The search window size for pilot PNl is determined based on a mobile located at point A. However, the same search window is used even if the mobile is at point B. This results in a waste of valuable searcher resources since it does not consider the location of the mobile within cell 104. If the mobile is at point B, the search window should be reduced in size relative to the search window required for a mobile located at point A.
D. Location Methods
Many techniques are being considered to provide for automatic location capability for mobiles. One technique involves measuring the time difference of arrival of signals from a number of cell sites. These signals are "triangulated" to extract location information. This technique reqtdres a high concentration of cell sites and/or an increase in the transmission power of the sites to be effective because typical CDMA systems require each mobile to transmit with only enough signal power to reach the closest cell site. This triangulation requires communication with at least three sites, requiring an increase in the concentration of cell sites or the signal power of each mobile station would have to be increased. Another approach involves the addition of GPS (Global Positioning System) functionality to a mobile. This approach requires a line-of-sight to four satellites, is somewhat slow, but is the most acctirate approach for locating a mobile.

A third approach sends aiding information to the mobile indicating in which frequency range the mobile should look for a GPS carrier. Most GPS receivers use what is known as a GPS satellite almanac to minimize a search performed by the receiver in the frequency domain for a signal from a visible satellite. The almanac is a 15,"300 bit block of coarse ephemeris and time model data for the entire consteilanon. The information in the almanac regrardin^ the position of the satellite and the conent time of day is approximate only. Without an almanac, the GPS receiver must conduct the widest possible frequency search to acquire a satellite signal. Additional processing is required to attain additional information that will aid in acquiring other satellites. The signal acquisition process can take several minutes due to the large number of frequency bins that need to be searched. Each frequency bin has a center frequency and predefined width. The availability of the almanac reduces the uncertainty in satellite Doppler and therefore the number of bins that must be searched. The satellite almanac can be extracted from the GPS navigation message or sent on the down forward link from the satellite to the mobile as a data or signaling message. On receipt of this information, the mobile performs GPS signal processing to determine its location.
What is needed is a method and apparatus can use the location information for a mobile in conjunction with pilot search techniques to improve the speed by which a mobile can search all pilots on an assigned frequency while the mobile is in control of the traffic channel. The invention should be able to utilize information about the physical location of the mobile to

determine the search window size for each pilot in the neighbor and candidate sets.
SUMMARY OF THE INVENTION
Broadly, the invention relates to a communication network. More specifically, the invention relates to an apparatus and method that utilizes the position-of a mobile in determining the search window size for a pilot in the neighbor and active candidate sets.
One embodiment of the invention provides a method for conducting a pilot signal search in a wireless communications network. First, the location of a mobile is determined within the network. This location is then used in determining search window sizes and search parameter information used to search all pilots identified in a pilot set. Search widow size is also determined based upon the location of the mobile and another component related to multipath effects for a transmitted pilot signal.
In another embodiment, the invention provides an article of manufacture containing digital information executable by a digital signal processing unit and used to conduct a pilot signal search in a wireless communications network. In another embodiment, the invention yields an apparatus used to conduct the pilot signal search. In one embodiment, the apparatus comprises at least one base station, wherein each base station transmits a pilot signal, and wherein the base station is used to determine the location of a mobile within the

communications network. The apparatus may also include at least one mobile, wherein a mobile is commuricatively coupled with at least one base station, and wherein the mobile uses search window sizes and other search parameter information transmitted to it to minimize the search time required for searching all pilot signals associated vvith a selected pilot set.
The invention pro\ddes its users vvith nuarierous advantages. One advantage is that the time required to search a set of pilot signals is reduced over known techniques. Another advantage is that valuable searcher resources are not wasted because a more efficient search may be conducted. The invention also provides a number of other advantages and benefits that should become apparent after reviewing the following detailed description of the invention.
BRIEF DESCRIPTION OF THE DRAWING
The nature, objects, and advantages of the invention will become more apparent to those skilled in the art after considering the following detailed description in connection with the accompanying drawings, in which like reference numerals designate like parts throughout, and wherein:
FIGURE 1 shows foxir adjacent cells in a wireless communication system in accordance with the invention;
FIGURE 2a illustrates a wireless communications apparatus utilizing a satellite positioning system in accordance with the invention;


DETAILED DESCRIFnON OF EXEMPLARY EMBODIMENTS
FIGURES 2a- 4 illustrate examples of varioiis method and apparatus aspects of the present invention. For ease of explanation, but without any limitation intended, these examples are described in the context of a digital signal processing apparatus. The digital signal processing apparatus used to execute a sequence of machine-readable instructions as referred to above may be embodied by various hardware components and intercormections. Varioias arrangements for these digital signal-processing apparatvises will become apparent to anyone schooled in the art after reading the below description of the methods involved.
OPERATION
The aforementioned patents and publications all describe a pilot signal used for acquisition. The use of a pilot signal enables the mobile to acquire a local base station in a timely manner. The mobile gets synchronization information, including a psuedorandom noise (PN) code phase offset, and relative signal power information from a received pilot signal carried on a pilot channel. Once a pilot channel has been acquired, the mobile may also acquire a


In a spread spectrum communication system, a pilot signal is vised to synchronize a mobile station in phase and frequency to the transmissions of a base station. In the exemplar}^ embodiment, the spread spectrtim communication system is a direct-sequence spread spectrum communication system. Examples of such systems are discussed in U.S. Patent No. 5,056,109, issued March 3,1992, entitled "METHOD AND APPARATUS FOR CONTROLLING TRANSMISSION POWER IN A CDMA MOBILE TELEPHONE SYSTEM," and U.S. Patent No. 5,103,459, issued April 7,1992, entitled "SYSTEM AND METHOD FOR GENERATING SIGNAL WAVEFORMS IN A CDMA CELLULAR TELEPHONE SYSTEM," both of which are assigned to the assignee of the present invention and incorporated by reference herein. In a direct-sequence spread spectrum communication system, the transmitted signals are spread over a frequency band greater than the minimum bandwidth necessary to transmit the information by modulating a

carrier wave by the data signal, then modulating the resulting signal again with a wideband spreading signal In a pilot signal of one embodiment, the data can be looked at as an all ones secuence. .A. linear feedback shift register, the implementation of which is described in detail in the aforementioned patents, typically generates the spreading signal. The spreading signal can be viewed as a rotating phasor of the form;
s.t; = .^e-"*-*
In order to accuire a base station, a mobile must synchronize to the received signals from the base station in both phase, **", and in frequency, To allow for the handoff of a call, the wireless system uses so-called "slotted" searching. In other words, a mobile performing slotted searching is assigned periodic windows (referred to as "slots") to search for other bases

stations to which it might handoff a call. Accordingly, mobiles search for pilot channel signals transmitted by surrounding bases stations in a predetermined window centered about the location in the PN code sequence at which the mobile expects the pilot channel to be. in accordance with standards set forth above.
The base station that the mobile is oirrentlv communicating mav send a search window size and other parameters, such as system time, to the mobOe. As the skilled artisan will readily appreciate, this reacquisition search window should be small as possible to avoid prolonged searching, but sufficiently large enough to account for typical internal dock errors. Further, the search parameters should be as particularized as possible.
In an exemplary embodiment, the present invention may reduce the search window size for PNl showm in Figure 1 by as much as one-third over currently known standard methods. For example, if the mobile is at point B, the search window for PNl could be reduced by a factor of three. If the mobile is at point C, the search v.indow could be reduced proportionally. In one embodiment, the invention accomplishes this by lising the physical location of the mobUe to particularize the search window size. In another embodiment, the invention uses the location to particular all of the search parameters.
To perform the method, the approximate location of the mobile must be known. This location may be determined in various ways known in the art and mentioned above. A discussion of one exemplary mobile location

determination technique is discussed in co-pending U.S. Pat. Application No. 09/040,501 entitled "SYSTEM AND METHOD FOR DErERMINING THE POSITION OF A WIRELESS CDMA TRANSSCEIVER," filed March 17,1998, assigned to the assignee of the present invention and incorporated ,bv reference herein. For purposes c: the present invention, a precise position determination is not necessa^\^ Coi:rse techniques may be used to determine the mobile"s location.
Once the mobile is in control of a traffic channel, the base station that is currently handling the communication transniuts a message telling the mobile the size of the search windows to be used for searching for the pilot signals contained in the neighbor set. The search window sizes are determined considering the mobile location within the serving cell. For example, and referring to Table 1 and Figure 1, the search window for PNl may be reduced from 12 to 4, reducing the window size from 160 chips to 14 chips, for a mobile located at position B. And because the search window size is reduced, demodulation expenses are reduced, and searches are completed expeditiously.
The searcher window size has at least two components, one component related to the geometric distance between the phone and the targeted pilot, and another related to multipath effects for a transmitted pilot signal. Accordingly, combining the effects of the two components minimizes selected search window size. In CDMA systems, space or path diversity is obtained by


through two or more cell-sites. Furthermore, path diversity mav be obtained by exploiting the multipath environment through spread spectrum processing by allowing a signal arriving with different propagation delays to be received and processed separately. Examples of path diversity are illiistrated in U.S. Patent No. 5,101p01, issued March 31.1?92, entitled "SOFT HANDOFF IN A CDMA CELLULAR TELEPHOXE S^"STEM", and U.S. Patent No. 5,109,390, issued April 28,1992, entitled "DFVTKSnY RECEIVER IN A CDMA CELLUTAR TELEPHONE SYSTEM", both assigned to the assignee of the present invention and incorporated by reference herein.
In another embodiment, the search parameters may also be chosen based upon the location of the mobile. When the mobile is in control of the traffic channel, a base station vvdU transmit search parameters to the mobile. These search parameters utilize knowledge of the location of the mobile to particularize or "customize" the search parameters. This particularizing is used to optimize searcher procedures. Optimizing search window size and the procedures used by the searcher to perform the search results in reduced search times.
In yet another embodiment, once the window size has been determined corresponding to geographical areas in a cell, the window sizes are stored in a memory imit. Searcher procedure parameters may also be stored. Assuming that the cells in the wireless system remain substantially unchanged, these

window sizes may be communicated to and used by any mobile that is located within the geographical area. The base station controller, knowing the location of a mobile, can look up the w-lndow size and/or the searcher procedure parameters and trarismit them to the mobile. In another embodiment, the mobile mav store the information.
.AJT.-^R-A TUS COMPONENTS -^ND INTERCONNECTIONS
Various apparatus embodiments are discussed below in relation to particular mobile location systems and supporting hardware embodiments. However, those schooled in the art will recognize that various location systems may be used.
Figure 2(a) is a diagram showing an implementation of a base station 202 and a mobile 204 in a sxTichronous CDMA communication network. The network is surroimded by buildings 206 and ground based obstacles 208. Base station 202 and mobile 204 are disposed in a GPS environment having several GPS satellites, of which four are shown 210,212,214 and 216. Such GPS enviroriments are well known; for example, see for example Hofmann-Wellenhof, B., et al., GPS Tneory and Practice, Second Edition, New York, NY: Springer-Verlag Wien, 1993. In a typical prior art GPS application, at least four satellites are required in order for a GPS receiver to determine its position. In contrast, the position of the remote station 204 may be determined using signals from as few as one GPS satellite and, in the simplest case, two other terrestrial based signals.

Figure 2(b) shows a block diagram of a CDMA network 220. The network 220 includes a mobile switching center (MSC) 222 having a base station controller (BSC) 224. A public si\-:tched telephone network (PSTM) 226 routes calls from traditional terrestrial based telephone lines and other networks (not shown) to and from MSC 222. MSC 222 routes calls from PSTN 226 to and from a source base station 22S associated with a first cell 230 and a target base station 232 associated with a second cell 234. In addition, MSC 222 routes calls between the base stations 225 and 232. The source base station 228 directs calls to the first mobile 256 within the first cell 230 via a first communications path 238. The first commuracations path 238 is a two-way link having a forward link 240 and a reverse link 242. Typically, when the base station 228 has established communications with the mobile 236, the forward link 240 includes a traffic channel.
A wireless positioning function (WPF) 242 is shown communicatively coupled to BSC 224 , but may be coupled directly or in-directly to other network elements such as MSC 222. \^TF 242 generally comprises a digital processing device, storage, and other elements (all not shown) comxnonly found in such devices. WPF 242 may be put to a variety of uses, such as estimating the one¬way time delay for a signal sent between the base station 228 and the mobile 236, or monitoring and accounting for the time offset between a reference time and a time of arrival of a signal.

Altnough each base station 22S and 232 is associated with only one cell, a base station controller often go\-ems or is associated with base stations in several cells. W"nen mobile 236 — oves from first cell 230 to second cell 234, mobile 236 begins com—unicating with the base station associated with the second ceil. This is commonly referred to as a "hand-off" to target base station 232. In a "soft" handoff, mobile 236 establishes a second contmunications link 244 with target base station 232 in addition to first commimications link 238 with source base station 22S. After mobile 236 crosses into second cell 234 and the channels with the second ceU has been established, the remote station may drop first communications link 238.
In a hard handoff, the operation of source base station 228 and target base station 232 typically are different enough that commxinications Hnk 244 between the source base station m.ust be dropped before the link to the target base station can be established. For exan\ple, when a source base station is within a CDMA system using a first frequency band and target base station is in a second CDMA system using a second frequency band, the remote station will not be able to maintain links to both base stations concurrently, since most remote stations do not have the ability to tune to two different frequency bands concurrentlv. When first mobile 236 moves from the first cell 230 to second cell 234, link 238 to source base station 228 is dropped and a new link is formed with target base station 232.


with a base station 3G2 or a wireless communication system, generally designated 304. It is to be understood that although a single base station 302 and a single mobile 300 are shown in Figure 3 for clarity of disclosure, the system 304 would typicaliy include other mobiles and base stations (not shown). In an exemplary embodiment, the system 304 implements code division multiple access ICDMA principles to discriminate one mobile signal from another. Details of a preferred CDMA system are set forth in the above referenced U.S. Patent N"o. 4,901307, issued February 13,1990 and entitled "SPREAD SPECTRUM MULTIPLE ACCESS COMMUNICATION SYSTEM USING SATELUTE OR TERRESTRIAL REPEATERS," assigned to the assignee of the present invention and incorporated by reference herein. As shown in the figure, mobile 300 includes a receiver/transmitter 306 that can communicate with base station 302 \da a wireless link 308. Further, mobile 300 includes control circuitry for controlling the reception and transmission of data by receiver/transmitter 306. In Figure 3, this control circuitry is rendered, for simplicity, as a digital signal processor 310. As also shown, processor 310 can access a data storage device 312. Although not shown, base station 302 may also house digital signal processing equipment and storage. As more fully disclosed below, data storage device 312 contains instructions that are executable by the digital signal processor 310. Accordingly, with the exception of the logical structure of data storage device 312, mobile 300 preferably is a CDMA mobile as is known in the art.


embodiment, internal dock 3:4 is a voltage controlled temperature controlled crystal oscillator (VCTCXO"i. However, it should be noted that other clock devices, whether or not cn^stal-based, are equally suitable for use with the present invention. Accordingly, the output signal of clock 314 is a sequence of clocking pulses that are sent to a counter 316, with the rate of clocking pulse output being controlled by con—oiling the voltage of an input signal to dock 314 from a clock power supply 31S in accordance with well-known prindples. Clock 314 may be synchronized with s\"stem time by the receipt of a timing message from base station 302 as discussed above.
Article of Maniofacture
The methods as described above may be implemented, for example, by operating a digital signal processing unit to execute a sequence of machine-readable instructions. These instructions may reside in various types of signal bearing media. In this respect, one aspect of the present invention concerns an artide of manufacture comprising a signal bearing media tangible embodying a program of machine-readable instructions executable by a digital signal
t
processing unit to perform a method to reduce the time needed to perform a pilot search.
This digital signal bearing medium may comprise, for example, RAM or an ASIC (neither shown) contained in a communications network. Alternatively, the instructions may be contained in another signal bearing

medium, such as a magnetic data storage medium, directly or indirectly accessible to the distal sisnaJ rrocessins unit. In an illustrative embodiment of the invention, the machine-readable instructions may comprise lines of compiled computer code, such as C, C-r-, or Java, or other suitable coding language commonly used by those skilled in the programming arts.
OTHER EMBODIMENTS While there have been sho%\-n what are presently considered to be exemplary embodiments of the invention, it wiU be apparent to those skilled in the art that various changes and modifications can be made without departing from the scope of the invention as defined by the appended claims.


WE CLAIM :
1. A method for conducting pilot signal search in a wireless communications system, comprising:
determining a location of a mobile station within said wireless communications system;
determining a plurality of search window sizes corresponding to a plurality of pilot signals based on said location of said mobile station with respect to a corresponding location of transmitting sources of said plurality of pilot signals.
2. The method as claimed in claim 1 comprising:
performing said pilot signal search for each of said plurality of pilot signals based on corresponding said determined plurality of search window sizes.
3. An apparatus for conducting pilot signal search in a wireless communications
system, comprising:
means (228,302) for determining a location of a mobile station within said wireless communications system;
means (224) for determining a plurality of search window sizes corresponding to a plurality of pilot signals based on said location of said mobile station with respect to a corresponding location of transmitting sources of said plurality of pilot signals.
4. The apparatus as claimed in claim 3 comprising:
means (310) for performing said pilot signal search for each of said plurality of pilot signals based on corresponding said determined plurality of search window sizes.

Documents:

in-pct-2002-0268-che assignment.pdf

in-pct-2002-0268-che claims duplicate.pdf

in-pct-2002-0268-che claims.pdf

in-pct-2002-0268-che correspondence others.pdf

in-pct-2002-0268-che correspondence po.pdf

in-pct-2002-0268-che description (complete) duplicate.pdf

in-pct-2002-0268-che description (complete).pdf

in-pct-2002-0268-che drawings.pdf

in-pct-2002-0268-che form-1.pdf

in-pct-2002-0268-che form-19.pdf

in-pct-2002-0268-che form-26.pdf

in-pct-2002-0268-che form-3.pdf

in-pct-2002-0268-che form-4.pdf

in-pct-2002-0268-che form-5.pdf

in-pct-2002-0268-che others.pdf

in-pct-2002-0268-che pct search report.pdf

in-pct-2002-0268-che pct.pdf

in-pct-2002-0268-che petition.pdf


Patent Number 202417
Indian Patent Application Number IN/PCT/2002/268/CHE
PG Journal Number 05/2007
Publication Date 02-Feb-2007
Grant Date 06-Oct-2006
Date of Filing 19-Feb-2002
Name of Patentee M/S. GLENDON W. MURPHY
Applicant Address 1927 MAPLE AVENUE, HUNTINGTON, WV 25703
Inventors:
# Inventor's Name Inventor's Address
1 GLENDON W. MURPHY 1927 MAPLE AVENUE, HUNTINGTON, WV 25703
PCT International Classification Number F16J 15/34
PCT International Application Number PCT/US99/29088
PCT International Filing date 1999-12-08
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 09/207,726 1998-12-08 U.S.A.