Localization of a mobile device in distributed antenna communications system

The present invention provides a method and apparatus for localization of a mobile device in a distributed antenna communications system. In accordance with an embodiment of the invention, a distributed antenna system includes a plurality of distributed antennas that are communicatively coupled to a hub. A mobile communications device to be located is communicatively coupled to the hub via one or more of the antennas. The method for locating the mobile device comprises: receiving a message at the hub that identifies the mobile device to be located; discriminating among communications signals received from each of the distributed antennas using a channel and a spreading code to identify a signal from the mobile device; identifying messages from the mobile device to be located; and determining which of the antennas is closest to the mobile device to be located by monitoring received signal strength of the identified signal.

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Description

This application is a reissue of application Ser. No. 11/728,123, filed Mar. 23, 2007, which issued as U.S. Pat. No. 8,005,050.

FIELD OF THE INVENTION

The present invention relates to the field of wireless communications and, more particularly, to localization of mobile devices in a distributed antenna communications system.

BACKGROUND OF THE INVENTION

A conventional distributed antenna system (DAS) provides indoor or outdoor coverage for wireless communications. Transmitted power is divided among several antennas in distributed locations so as to provide a large coverage area using less transmitted power than would be required by a single antenna system. The antennas of a typical DAS are connected to a cellular base station and are used for cellular mobile communications.

It can be desired to locate a mobile device within a DAS, for example, for emergency purposes (e.g., 911 calls). However, because the received signals from the distributed antennas are typically combined in the uplink to the base station receiver, the base station has no ability to determine which of the distributed antennas is closest to the transmitting mobile device.

SUMMARY OF THE INVENTION

The present invention provides a method and apparatus for localization of a mobile device in a distributed antenna communications system. In accordance with an embodiment of the invention, a distributed antenna system includes a plurality of distributed antennas that are communicatively coupled to a hub. A mobile communications device to be located is communicatively coupled to the hub via one or more of the antennas. The method for locating the mobile device comprises: receiving a message at the hub that identifies the mobile device to be located; discriminating among communications signals received from each of the distributed antennas using a channel and a spreading code to identify a signal from the mobile device; and determining which of the antennas is closest to the mobile device to be located by monitoring received signal strength of the identified signal.

In accordance with an alternative embodiment of the method, the method comprises: receiving an indication at the hub that notifies the hub of commencement of locating the mobile device; instructing the mobile device to modulate its output power; identifying a received signal from the mobile device having modulated output power; and identifying a particular antenna unit among the plurality having a highest received power level from the mobile device.

In accordance with an another alternative embodiment of the method, the method comprises: receiving a message at the hub that identifies the mobile device to be located; identifying a received signal from the mobile device in a frequency channel and timeslot of the mobile device; and determining which of the antennas is closest to the mobile device to be located by monitoring received signal strength of the identified signal

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described with respect to particular exemplary embodiments thereof and reference is accordingly made to the drawings in which:

FIG. 1 illustrates a distributed antenna communications system in accordance with an embodiment of the present invention;

FIG. 2 illustrates a method of locating a mobile device in a distributed antenna communications system in accordance with an embodiment of the present invention;

FIG. 3 illustrates a timing diagram showing modulated output power of a mobile device being located in accordance with an embodiment of the present invention;

FIG. 4 illustrates a distributed antenna communications system in accordance with an alternative embodiment of the present invention;

FIG. 5 illustrates an alternative method of locating a mobile device in a distributed antenna communications system in accordance with an embodiment of the present invention;

FIG. 6 illustrates distributed antenna units having location transmitters in accordance with an embodiment of the present invention;

FIG. 7 illustrates distributed antenna units having signal strength measurement capability in accordance with an embodiment of the present invention;

FIG. 8 illustrates a distributed antenna communications system having multiple base stations in accordance with an embodiment of the present invention;

FIG. 9 illustrates a timing diagram for responding to multiple requests to locate mobile devices in accordance with an embodiment of the present invention; and

FIG. 10 illustrates a distributed antenna communications system having multiple base stations in accordance with an alternative embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a distributed antenna communications system 100 in accordance with an embodiment of the present invention. The system 100 includes a communications hub 102, a base station 104, a plurality of distributed antennas 106a-n coupled to ports of the hub 102 and one or more mobile communications devices 108a-n that are communicatively coupled to the hub 102 via the antennas 106a-n. The base station 104 may be located at the site of a cellular service provider and may be coupled to a telephone network via a backhaul 110. The hub 102 may be located at the premises of a telecommunications subscriber with the antennas 106a-n being distributed throughout the premises. For example, the hub 102 may be located within a building (e.g., in a utility room) with the antennas distributed throughout the building so as to provide indoor coverage areas for mobile devices 108a-n. The mobile devices 108a-n may be, for example, cell phones. While three mobile devices 108a-n and three antennas 106a-n are illustrated, it will be apparent that more or fewer of either may be present. In an embodiment, up to eight antennas 106a-n may be coupled to a single hub 102. Additionally, one or more of the antennas 106a-n may be located outdoors.

The system 100 preferably provides for two-way communications. For the downlink, telecommunications signals are received by the base station 104 from the telephone network and distributed to the antennas 106a-n. To accomplish this, a transceiver 112 may receive the downlink signal from the base station 104. The transceiver 112 then amplifies the downlink signal to an appropriate level for forwarding to a distribution node 114. The distribution node 114 then repeats and distributes the signal to a plurality of transceivers 116a-n such that each of the transceivers 116a-n receives a copy of the downlink signal. The transceivers 116a-n each transmits the signal received from the distribution node 114 via a corresponding one of the antennas 106a-n. The mobile devices 108a-n each pick up the downlink signal from one or more of the antennas 106a-n.

For the uplink, signals from the mobile devices 108a-n are received by the transceivers 116a-n via the antennas 106a-n. The signals are then forwarded to the distribution node 114 which combines the signals (e.g., by simple summation) into a combined signal. The combined signal is transmitted to the base station 104 by the transceiver 112. The base station 104 then forwards the combined signal to the telephone network.

In an embodiment, the downlink signal from the base station 104 is RF (Radio Frequency). For example, this signal is communicated via a cable or via a wireless link between the transceiver 112 and the base station 104. In this case, the transceiver 112 may down-convert the downlink signal from RF to IF. This signal is then distributed to the transceivers 116a-n in IF. The transceivers 116a-n up-convert the IF signal to RF (Radio Frequency) before transmitting the signal to the mobile devices 108a-n. For the uplink, the transceivers 116a-n down-convert RF signals received from the mobile devices 108a-n to IF. These IF signals are then processed and combined for delivery to the transceiver 112 in IF. The transceiver 112 then up-converts the IF signal to RF for delivery the base station 104

So that multiple mobile devices 108a-n may communicate via the system 100 simultaneously, each communicates in a different channel. For example, CDMA (Code-Division, Multiple Access) protocols for cellular communication, such as UMTS (Universal Mobile Telecommunications System), or TDMA (Time-Division, Multiple-Access) protocols for cellular communication, such as GSM (Global System for Mobile Communications) may be employed by the system 100. Thus, for the downlink, the same signal including the various channels is transmitted via each of the antennas 106a-n so that it may be received by any of the mobile devices 108a-n without regard to which of the antennas 106a-n is closest to a particular one of the mobile devices. For the up-link, the signal from a particular mobile device may be picked up by one or more antennas 106a-n. As shown in FIG. 1, the signal from device 108a is picked up by antennas 106a and 106b, though the signal may be stronger at one of the antennas than the other. As is also shown in FIG. 1, the signal from device 108b is picked up only by antenna 106n. The signal from device 108n is also picked up only by the antenna 106n. All of the signals picked up by any of the antennas 106-n are combined at node 114 and included in the combined signal received at the base station 104.

Because the signals from the mobile devices 108a-n are combined, the base station 104 is not able to determine which of the antennas 106a-n is picking up the signal from a particular mobile device and, thus, the base station 104 cannot determine the location of that mobile device. It may be desired, however, to locate a particular mobile device within the system 100, for example, for emergency purposes (e.g., 911 calls).

FIG. 2 illustrates a method 200 of locating a mobile device in a distributed antenna communications system in accordance with an embodiment of the present invention. The method 200 may be employed within the system 100 of FIG. 1. In a step 202, localization is initiated. For example, the base station 104 may receive an emergency 911 call from one of the mobile units 108a or 108b. The base station 104 may then initiate localization of the calling mobile unit so as to assist emergency personnel to locate the caller. This may be accomplished by the base station 104 sending a message to the hub 102 which instructs elements of the hub 102 that localization is being initiated. The message sent to the hub 102 may also identify the mobile device to be localized, though this is not always necessary. If the mobile device is identified by the message, the message may identify the mobile device by the frequency channel (e.g. for UMTS) it is operating in or by its frequency channel and timeslot (e.g. for GSM). As shown in FIG. 1, a hub controller 118 may receive this message from the base station 104.

In addition, in step 202, the mobile device being localized is instructed to modulate its output power so that its output power changes over time. For example, the base station 104 may send a message to the particular device instructing it to adjust its output power to first level (e.g., 10 mW). Then, the base station 104 may send another message instructing the device to adjust its output power to a second level (e.g., 50 mW). The base station 104 may send a series of such messages to the particular mobile device being localized so that the level of its output power follows an identifiable pattern.

FIG. 3 illustrates a timing diagram showing modulated output power of a mobile device being located in accordance with an embodiment of the present invention. As shown in FIG. 3, the mobile device adjusts its output power to a first level L1 at a time t0 in response to a received instruction. Then, the mobile device adjusts its output power to a second level L2 at a time t1 in response to another received instruction. Later, the mobile device adjusts it output power to the first level L1 at time t2 in response to yet another received instruction. In this manner, the output power level of the mobile device follows an identifiable pattern. While FIG. 3 shows the level oscillating between two levels at uniform time intervals, this is not necessary. All that is needed for the output power to follow a pattern which is distinct from that of any other mobile device communicating within the system 100.

Returning to FIG. 2, in a step 204, one or more of the antennas 106a-n that receives the modulated signal are identified. This may be accomplished by the hub 102 measuring the strength of the different signals received from each of the distributed antennas 106a-n. As shown in FIG. 1, a signal strength meter 120 is coupled to lines 122a-n from each of the transceivers 116a-n. The signal strength meter may simultaneously monitor all of the lines 122a-n or it may cycle through the lines 122a-n, measuring signal strength on the lines one-at-a-time. Further, the signal strength meter 120 may be tuned to the appropriate channel identified by the base station 104 for the mobile device to be located. In addition, for TDMS protocols, measurement intervals may optionally be timed to coincide with the timeslot being used by the mobile device. To accomplish this, the base station 104 may provide framing reference information to the controller 118. Alternatively, the signal strength meter can measure the combined strength of a frequency range that includes several channels without regard to timeslot.

In response to the initiation message sent in step 202, the controller 118 may then monitor the strength of the signals measured by the meter 120 and identify which signal or signals received from the distributed antennas 106a-n contains the distinct power modulation pattern. If only one of the signals contains the pattern, this indicates that the mobile device sending the pattern is located in the vicinity of the one of the antennas 106a-n that received that particular signal. Because the location of each of the antennas 106a-n is known, the location of the mobile device is determined from this information.

If more than one of the signals received from the distributed antennas 106a-n contain the distinct power modulation pattern, the controller 118 may further determine which of the distributed antennas 106a-n receives the highest level of the distinct modulation pattern in step 206. This indicates that the mobile device sending the pattern is located closest to the one of the antennas that received the strongest level of the particular signal. Because the location of each of the antennas 106a-n is known, the location of the mobile device is determined from this information. Step 206 need not be performed if only one antenna receives a signal from the mobile device whose location is to be determined.

The method described above can be used to determine the location of a mobile device using CDMA or TDMA protocols and does not require the hub 102 to have knowledge of the particular frequency channel or timeslot of the mobile device. In an alternative embodiment applicable to TDMA protocols, such as GSM, the mobile device need not modulate its output power to be localized. Rather, the frequency channel and timeslot being used by the mobile device can be used to uniquely identify the signal from the mobile device. This is because it can be expected that no other device will be operating in the same channel and timeslot at the same time. To determine which of the antennas 106a-n is closest to the mobile device, the signal strength from each of the antennas 106a-n is measured at the frequency and the timeslot of the mobile device and compared to determine which is strongest and, therefore, closest to the mobile device. More particularly, in a first step, localization is initiated by the base station 104 sending a message to the hub 102 which identifies the mobile device to be localized. The message may identify the mobile device by its frequency channel and timeslot. In a second step, the strength of the signal received from each of the distributed antennas 106a-n is measured for the frequency channel and timeslot of the mobile device being located. This may be accomplished by tuning the signal strength meter 120 to the frequency channel being used by the mobile device and by the controller 118 timing measurement intervals so that they coincide with the timeslot being used by that mobile device (using framing reference information received from the base station 104). As before, the signal strength meter 120 may simultaneously monitor all of the lines 122a-n or it may cycle through the lines 122a-n, measuring signal strength on the lines one-at-a-time. If a signal is detected in the frequency channel and timeslot from only one of the antennas 106a-n, this indicates that the mobile device is located in the vicinity of that one of the antennas. Because the location of each of the antennas 106a-n is known, the location of the mobile device is determined from this information. If more than one of the distributed antennas 106a-n picks up the signal in the frequency channel and timeslot of the mobile device being located, the controller 118 may further determine which of the distributed antennas 106a-n receives the highest level in that frequency channel and timeslot. This indicates that the mobile device is located closest to the one of the antennas that received the strongest level in the frequency channel and timeslot.

FIG. 4 illustrates a distributed antenna communications system 100′ in accordance with an alternative embodiment of the present invention. This embodiment is applicable to CDMA protocols, such as UMTS that use spread spectrum channel modulation schemes. The system 100′ of FIG. 4 may be identical to the system 100 of FIG. 1 with differences described below. Accordingly, like reference numerals are used for corresponding elements of FIGS. 1 and 4. The system 100′ differs from the system 100 of FIG. 1 in that a de-spreader 124 is provided. The de-spreader 124 uses spreading codes to discriminate among channels included in the signals received from the mobile devices 108a-n on lines 122a-n (via the antennas 106a-n and transceivers 116a-n). This may be accomplished by the de-spreader converting the IF signals to baseband and by applying a spreading code. Thus, by using the spreading code of the mobile device to be located, the de-spreader removes components of the received signal that are contributed by other mobile devices operating within the system 100′. The meter 120 and controller 118 monitor the levels corresponding to the identified channel and compares those levels for each of the antennas 106a-n to determine which of the antennas 106a-n is closest to the mobile device being located.

FIG. 5 illustrates a method 500 of locating a mobile device in a distributed antenna communications system in accordance with an embodiment of the present invention. The method 500 may be employed within the system 100′ of FIG. 4. In a step 502, localization is initiated. For example, the base station 104 may receive an emergency 911 call from one of the mobile units 108a or 108b. The base station 104 may then initiate localization of the calling mobile unit so as to assist emergency personnel to locate the caller. This may be accomplished by the base station 104 sending a message to the hub 102 which identifies the mobile device to be localized. The message may, for example, identify the mobile device by its frequency channel and unique transmission spreading code. The hub controller 118 may receive this message from the base station 104.

In a step 504, one or more signals received by the hub 102 from the mobile devices 108a-n are identified as originating from the mobile device whose location is to be determined. This may be accomplished by the de-spreader 124 using the spreading code to discriminate the signal from the mobile device being located from the other signals received from the transceivers 116a-n of the hub 102. The signal strength meter 120 measures the level of the discriminated signal from each of the antennas 106a-n. If the discriminated signal is picked up by only one of the antennas, this indicates that the mobile device is located in the vicinity of the one of the antennas 106a-n that picked up the signal. Because the location of each of the antennas 106a-n is known, the location of the mobile device is determined from this information.

If more than one of the distributed antennas 106a-n picked up the discriminated signal from the mobile device, the controller 118 may further determine which of the distributed antennas 106a-n receives the highest level of the signal in step 506. To accomplish this, the signal strength meter 120 and controller 118 may monitor and compare the signal levels received from the antennas that are picking up the signal to determine which has the highest level. Because the location of each of the antennas 106a-n is known, the location of the mobile device is determined from this information. Step 506 need not be performed if only one antenna receives a signal from the mobile device whose location is to be determined.

Once the particular mobile device is located using any of the localization methods described herein, additional steps may be taken to send a notification of the location to personnel for facilitating locating the mobile device and, thus, the caller. For example, an e-mail may be automatically generated by the controller 118 and sent to an emergency call processing center via the base station 104 and a wide area computer network (e.g. the Internet) so that emergency personnel can be informed of the caller's location. As another example, a message or signal may be sent by the controller 118 to circuitry associated with the nearest antenna which then activates an optical and/or acoustical signal which can be perceived by emergency personnel or which sends a message which can be perceived by equipment carried by emergency personnel.

FIG. 6 illustrates an embodiment in which each distributed antenna 106a-n is associated with an antenna unit 126a-n having a location emitter 128a-n. Once the antenna closest to the mobile device being located is identified by the controller 118 (FIGS. 1 and 4), the controller 118 may send a signal to the antenna unit 126a-n associated with that particular antenna 106a-n, instructing activation of its location emitter 128a-n. The activation signal may be sent via a wired connection (e.g. via the antenna unit's connection to the hub) or via a wireless connection (e.g. sent directly to the antenna unit).

The particular location emitter 128a-n which is determined to be closest to the mobile device being located may then emit a human perceptible signal, such as an optical signal (e.g. a flashing light), or an audible signal (e.g. a beeping sound). This emitted signal may then be used to facilitate personnel in locating that particular antenna unit and, thus, the particular mobile device and caller. Alternatively, the particular location emitter 128a-n may send short range wireless message to equipment carried by personnel attempting to locate the caller. For example, the location emitters 128a-n may operate in accordance with a wireless personal area network (PAN) protocol such as Bluetooth or ZigBee. This message may include location information which facilitates personnel in locating the particular antenna unit and, thus, the particular mobile device and caller. For example, the location information may be in the form of a text message, such as “Go up the stairs to the second floor and proceed down the hallway to the right” or “The caller is located in the southeastern wing of the building.”

In the embodiments described above, signal strength information is obtained by measuring the signals at the hub 102. In an alternative embodiment, the signal strength measurements may be performed at the antennas. FIG. 7 illustrates distributed antenna units having signal strength measurement capability in accordance with an embodiment of the present invention. As shown in FIG. 7, each antenna unit 126a-n is equipped with a corresponding signal measurement device 130a-n. Each measurement device 130a-n may include a controller, a signal strength meter, and, optionally, a de-spreader which operate similarly to the hub controller 118, meter 120 and de-spreader 124 described above in reference to FIGS. 1 and 4. More particularly, messages received by the hub controller 118 from the base station 104 may be forwarded to the controllers of the measurement devices 130a-n. These messages notify the measurement devices 130a-n of initiation of localization of a mobile device and may also identify the mobile device to be located. In response, each measurement device 130a-n takes signal strength measurements (as described herein with respect to the meter 120 of FIGS. 1 and 4) and reports the results to the hub controller 118. In an embodiment, these signal strength measurements may be performed in an identified channel and timeslot using framing information or using a spreading code received from the hub controller 118.

The hub controller 118 then uses the received results to determine whether any of the antennas 106a-n are picking up the signal from the mobile device to be located. If only one antenna 106a-n is picking up the signal, this indicates that the mobile device is located in the vicinity of the one of the antennas 106a-n that picked up the signal. If more than one of the distributed antennas 106a-n picked up the signal from the mobile device, the controller 118 may further determine which of the distributed antennas 106a-n receives the highest level of the signal by comparing the signal levels reported by the corresponding antenna units 126a-n.

In the embodiments described above, a single base station 104 is coupled to the hub 102. In other embodiments, two or more base stations may be coupled to the hub 102. FIG. 8 illustrates a distributed antenna communications system having multiple base stations 104a-n in accordance with an embodiment of the present invention. As shown in FIG. 8, each of the base stations 104a-n is coupled to the transceiver 112 for uplink and downlink communications with the mobile units 108a-n (FIGS. 1 and 4). In addition, each of the base stations 104a-n is coupled to the controller 118 via a corresponding one of communication links 132a-n and via a register 134. Each of the links 132a-n carries bidirectional serial communications. Thus, each of the links 132a-n may include a first signal line for communication from the corresponding base unit 104a-n to the controller 118 and a second signal line for communication from the controller 118 to the corresponding base station 104a-n.

When any of the base stations 104a-n determines that a mobile device is to be located (e.g. in response to receiving a 911 call), that base station 104a-n raises its signal line to the controller 118. This sets a corresponding indicator bit in the register 134. The set indicator bit indicates to the controller 118 that the corresponding base station is ready to initiate localization of a mobile device. If the controller 118 is not already responding to a set indicator bit from another base station, the controller 118 responds to the base station by raising the corresponding signal line to the base station. Upon receiving this response, the base station instructs the mobile unit being located to modulate its output power. The controller 118 then determines the location of the mobile unit as described herein with reference to FIGS. 1 and 3. Once the mobile device has been located, the controller 118 may clear (i.e. reset) the indicator bit in the register 134. The controller 118 may then respond to any other set indicator bits in the register 134. In this manner, the controller 118 may process multiple requests to locate mobile devices in the order in which they are received.

FIG. 9 illustrates a timing diagram for responding to multiple requests to locate mobile devices in accordance with an embodiment of the present invention. As shown in FIG. 9, after a first request (Request1) is received by the controller 118 and no other request is currently pending, the first request is processed by localizing the mobile device corresponding to the first request. Then, while the first request is still being processed, a second request (Request2) is received. Localizing of the mobile device corresponding to the second request is commenced after the localizing of the mobile device corresponding to the first request is completed.

FIG. 10 illustrates a distributed antenna communications system having multiple base stations in accordance with an alternative embodiment of the present invention. As shown in FIG. 10, each of the plurality of base stations 104a-n is coupled to the transceiver 112 for uplink and downlink communications with the mobile units 108a-n (FIGS. 1 and 4). In addition, each of the base stations 104a-n is coupled to the controller 118 via a shared communication bus 136. Thus, each of the base stations 104a-n may communicate with the controller 118 via the bus 136.

When any of the base stations 104a-n determines that a mobile device is to be located (e.g. in response to receiving a 911 call), that base station 104a-n sends a message to the controller 118. The message identifies the originating base station and notifies the controller 118 that the base station is ready to commence localization of a mobile device. The message may also identify the mobile device to be located such as by its frequency channel and timeslot or spreading code. If the controller 118 is not already responding to such a request message from another base station (or to a prior request from the same base station), the controller 118 responds to the base station with a response message which notifies the base station that its request is ready to be processed. Upon receiving this response, the base station may instruct the mobile unit being located to modulate its output power (as described above with reference to FIGS. 1 and 3). Alternatively, the controller 118 may localize the mobile device by performing signal strength measurements for the identified frequency channel, frequency channel and timeslot or by using an appropriate spreading code (as described herein).

Once the mobile device has been located, the controller 118 may then respond to any other request messages. In this manner, the controller 118 may process multiple requests to locate mobile devices in the order in which they are received. While the embodiments of FIGS. 8 and 10 show three base stations 104a-n, it will be apparent that the system may be implemented with one, two or more than three base stations.

The foregoing detailed description of the present invention is provided for the purposes of illustration and is not intended to be exhaustive or to limit the invention to the embodiments disclosed. Accordingly, the scope of the present invention is defined by the appended claims.

Claims

1. A method for locating a mobile communications device in a distributed antenna system in which plural distributed antennas are communicatively coupled to a hub and in which the mobile device is communicatively coupled to the hub via one or more of the antennas, the method comprising:

receiving at the hub communication signals from the plural distributed antennas;
combining the received communication signals to produce a combined signal;
forwarding the combined signal to a base station, wherein the mobile device is communicatively coupled to the base station via the hub;
receiving a message at the hub that identifies the mobile device to be located;
discriminating, at the hub, among communications signals received from each of the distributed antennas using a channel and a spreading code to identify a signal from the mobile device; and
determining which of the antennas is closest to the mobile device to be located by monitoring received signal strength of the identified signal.

2. The method according to claim 1, wherein the mobile device communicates using a CDMA protocol for cellular communications.

3. The method according to claim 1, wherein the message identifies the mobile device according to its channel and the spreading code.

4. The method according to claim 1, further comprising sending a notification of the location of the antenna determined to be closest to the mobile device for facilitating locating the mobile device.

5. The method according to claim 1, wherein a notification is sent from an emitter associated with the antenna determined to be closest via a wireless personal area network.

6. The method according to claim 1, wherein a notification is sent from an emitter associated with the antenna determined to be closest in the form of a human perceptible signal.

7. The method according to claim 1, wherein the notification is sent via a wide area network.

8. The method according to claim 1, wherein the monitoring of received signal strength of the identified signal is performed at the hub.

9. The method according to claim 1, wherein the monitoring of received signal strength of the identified signal is performed at the antennas.

10. The method according to claim 1, wherein a plurality of base stations are coupled to the hub and further comprising queuing the message at the hub until a prior request to locate a mobile device has been processed.

11. A distributed antenna system comprising:

a base station configured for communication with a telecommunications network;
a multi-port hub connected to the base station that receives communication signals on a plurality of ports of the multi-port hub from a plurality of distributed antennas and combines the received communication signals for forwarding a combined signal to the base station, wherein the multi-port hub is configured to receive a message at the multi-port hub that identifies the mobile device to be located, and wherein the multi-port hub comprises:
a de-spreader that uses a spreading code to identify a signal from a mobile communications device to be located; and
a controller that determines which of the antennas is closest to the mobile device to be located by monitoring received signal strength of the identified signal.

12. A method for locating a mobile device in a distributed antenna system in which plural distributed antennas are communicatively coupled to a hub and in which the mobile device is communicatively coupled to the hub via one or more of the antennas, the method comprising:

receiving at the hub communication signals from the plural distributed antennas;
combining at the hub the received communication signals to produce a combined signal;
forwarding the combined signal from the hub to a base station, wherein the mobile device is communicatively coupled to the base station via the hub;
receiving an indication at the hub that notifies the hub of commencement of locating the mobile device;
instructing in connection with the mobile device to modulate modulating its output power; for locating the mobile device: identifying, at the hub, a received signal from the mobile device having modulated output power; and identifying a particular antenna unit among the plurality having a highest received power level for the received signal from the mobile device having modulated output power.

13. The method according to claim 12, wherein the mobile device communicates using a CDMA protocol for cellular communications.

14. The method according to claim 12 36, wherein the indication is a message that identifies the mobile device according to its frequency channel or according to its frequency channel and timeslot.

15. The method according to claim 12, wherein the mobile device communicates using a TDMA protocol for cellular communications.

16. The method according to claim 12, further comprising sending a notification of the location of the antenna determined to be closest to the mobile device for facilitating locating the mobile device.

17. The method according to claim 12, wherein a notification is sent from an emitter associated with the antenna determined to be closest via a wireless personal area network.

18. The method according to claim 12, wherein a notification is sent from an emitter associated with the antenna determined to be closest in the form of a human perceptible signal.

19. The method according to claim 12 18, wherein the notification is sent via a wide area network.

20. The method according to claim 12, wherein the identifying the received signal from the mobile device having modulated output power is performed at the hub.

21. The method according to claim 12, wherein the identifying the received signal from the mobile device having modulated output power is performed at the antennas.

22. The method according to claim 12 36, wherein a plurality of base stations are coupled to the hub and wherein the indication is set in a register until a prior request to locate a mobile device has been processed.

23. A distributed antenna system comprising:

a base station configured for communication with a telecommunications network; and
a multi-port hub connected to the base station that receives communication signals on a plurality of ports of the multi-port hub from a plurality of distributed antennas and combines the received communication signals for forwarding a combined signal to the base station, wherein the multi-port hub determines which of the antennas is closest to a mobile device to be located by the base station by instructing in connection with the mobile device to modulate modulating its output power, by the hub identifying a received signal from the mobile device by its modulated output power, and identifying a particular antenna unit among the plurality having a highest received power level for received signal from the mobile device by its modulated output power.

24. A method for locating a mobile communications device in a distributed antenna system in which plural distributed antennas are communicatively coupled to a hub and in which the mobile device is communicatively coupled to the hub via one or more of the antennas, the method comprising:

receiving at the hub communication signals from the plural distributed antennas;
combining at the hub the received communication signals to produce a combined signal;
forwarding the combined signal from the hub to a base station, wherein the mobile device is communicatively coupled to the base station via the hub;
receiving a message at the hub that identifies the mobile device to be located;
identifying, at the hub, a received signal from the mobile device in a frequency channel and timeslot of the mobile device; and
determining which of the antennas is closest to the mobile device to be located by monitoring received signal strength of the identified signal.

25. The method according to claim 24, wherein the mobile device communicates using a TDMA protocol for cellular communications.

26. The method according to claim 24, wherein the message identifies the mobile device according to its frequency channel and timeslot.

27. The method according to claim 24, further comprising sending a notification of the location of the antenna determined to be closest to the mobile device for facilitating locating the mobile device.

28. The method according to claim 24, wherein a notification is sent from an emitter associated with the antenna determined to be closest via a wireless personal area network.

29. The method according to claim 24, wherein a notification is sent from an emitter associated with the antenna determined to be closest in the form of a human perceptible signal.

30. The method according to claim 24 29, wherein the notification is sent via a wide area network.

31. The method according to claim 24, wherein the monitoring of received signal strength of the identified signal is performed at the hub.

32. The method according to claim 24, wherein the monitoring of received signal strength of the identified signal is performed at the antennas.

33. The method according to claim 24, wherein a plurality of base stations are coupled to the hub and further comprising queuing the message at the hub until a prior request to locate a mobile device has been processed.

34. A distributed antenna system comprising:

a base station configured for communication with a telecommunications network; and
a multi-port hub connected to the base station that receives communication signals on a plurality of ports of the multi-port hub from a plurality of distributed antennas and combines the received communication signals for forwarding a combined signal to the base station, wherein the multi-port hub determines which of the antennas is closest to a mobile device to be located by identifying a received signal from the mobile device by its frequency channel and timeslot, and identifying a particular antenna unit among the plurality having a highest received power level for the received signal from the mobile device.

35. The method of claim 1, further comprising: receiving a message at the hub that identifies the mobile device to be located.

36. The method of claim 12, further comprising: receiving an indication at the hub that notifies the hub of commencement of locating the mobile device; and instructing the mobile device to-modulate its output power.

37. The method of claim 24, further comprising: receiving a message at the hub that identifies the mobile device to be located.

Referenced Cited
U.S. Patent Documents
3586968 June 1971 Barjot
3733430 May 1973 Thompson et al.
3866121 February 1975 Nakamura et al.
4183054 January 8, 1980 Patisaul et al.
4433335 February 21, 1984 Wind
4451916 May 29, 1984 Casper et al.
4611323 September 9, 1986 Hessenmiiller
4628501 December 9, 1986 Loscoe
4642426 February 10, 1987 Blackburn
4654843 March 31, 1987 Roza et al.
4667319 May 19, 1987 Chum
4691292 September 1, 1987 Rothweiler
4733223 March 22, 1988 Gilbert
4760573 July 26, 1988 Calvignac et al.
4789993 December 6, 1988 Ryu
4799062 January 17, 1989 Sanderford, Jr. et al.
4999831 March 12, 1991 Grace
5193109 March 9, 1993 Chien-Yeh Lee
5212831 May 18, 1993 Chuang et al.
5227679 July 13, 1993 Woo
5243598 September 7, 1993 Lee
5263177 November 16, 1993 Schieve et al.
5303287 April 12, 1994 Laborde
5317323 May 31, 1994 Kennedy et al.
5321736 June 14, 1994 Beasley
5321849 June 14, 1994 Lemson
5327144 July 5, 1994 Stilp et al.
5339184 August 16, 1994 Tang
5351146 September 27, 1994 Chan et al.
5381459 January 10, 1995 Lappington
5400391 March 21, 1995 Emura et al.
5461627 October 24, 1995 Rypinski
5508708 April 16, 1996 Ghosh et al.
5512908 April 30, 1996 Herrick
5519691 May 21, 1996 Darcie et al.
5545397 August 13, 1996 Spielvogel et al.
5563606 October 8, 1996 Wang
5566168 October 15, 1996 Dent
5602903 February 11, 1997 LeBlanc et al.
5603080 February 11, 1997 Kallander et al.
5621414 April 15, 1997 Nakagawa
5621786 April 15, 1997 Fischer et al.
5627879 May 6, 1997 Russell et al.
5631916 May 20, 1997 Georges et al.
5642405 June 24, 1997 Fischer et al.
5644622 July 1, 1997 Russell et al.
5657374 August 12, 1997 Russell et al.
5668562 September 16, 1997 Cutrer et al.
5682256 October 28, 1997 Motley et al.
5701583 December 23, 1997 Harbin et al.
5708961 January 13, 1998 Hylton et al.
5732076 March 24, 1998 Ketseoglou et al.
5761619 June 2, 1998 Danne et al.
5765097 June 9, 1998 Dail
5765099 June 9, 1998 Georges et al.
5774789 June 30, 1998 Van der Kaay et al.
5781541 July 14, 1998 Schneider
5781859 July 14, 1998 Beasley
5784028 July 21, 1998 Corman et al.
5802173 September 1, 1998 Hamilton-Piercy et al.
5805983 September 8, 1998 Naidu et al.
5809395 September 15, 1998 Hamilton-Piercy et al.
5809419 September 15, 1998 Schellinger et al.
5809422 September 15, 1998 Raleigh et al.
5815538 September 29, 1998 Grell et al.
5822324 October 13, 1998 Kostresti et al.
5833493 November 10, 1998 Hung
5852651 December 22, 1998 Fischer et al.
5875179 February 23, 1999 Tikalsky
5878325 March 2, 1999 Dail
5883882 March 16, 1999 Schwartz
5887261 March 23, 1999 Csapo et al.
5907544 May 25, 1999 Rypinski
5912641 June 15, 1999 Dietrich
5930682 July 27, 1999 Schwartz et al.
5945948 August 31, 1999 Buford et al.
5946622 August 31, 1999 Bojeryd
5969679 October 19, 1999 Bolliger et al.
5969837 October 19, 1999 Farber et al.
5970414 October 19, 1999 Bi et al.
5983070 November 9, 1999 Georges et al.
5987014 November 16, 1999 Magill et al.
5987326 November 16, 1999 Tiedemann, Jr. et al.
6005884 December 21, 1999 Cook et al.
6014546 January 11, 2000 Georges et al.
6034950 March 7, 2000 Sauer et al.
6078812 June 20, 2000 Mintz
6084547 July 4, 2000 Sanderford et al.
6108113 August 22, 2000 Fee
6108550 August 22, 2000 Wiorek et al.
6108626 August 22, 2000 Cellario et al.
6111541 August 29, 2000 Karmel
6112086 August 29, 2000 Wala
6125260 September 26, 2000 Wiedeman et al.
6127975 October 3, 2000 Maloney
6128496 October 3, 2000 Scheinert
6147786 November 14, 2000 Pan
6157659 December 5, 2000 Bird
6157810 December 5, 2000 Georges et al.
6175308 January 16, 2001 Tallman et al.
6181253 January 30, 2001 Eschenbach et al.
6181687 January 30, 2001 Bisdikian
6188693 February 13, 2001 Murakami
6192216 February 20, 2001 Sabat, Jr. et al.
6195342 February 27, 2001 Rohani
6198558 March 6, 2001 Graves et al.
6201803 March 13, 2001 Munday et al.
6204813 March 20, 2001 Wadell et al.
6222660 April 24, 2001 Traa
6226274 May 1, 2001 Reese et al.
6236365 May 22, 2001 LeBlanc
6249252 June 19, 2001 Dupray
6262981 July 17, 2001 Schmutz
6275990 August 14, 2001 Dapper et al.
6285881 September 4, 2001 Huang
6317884 November 13, 2001 Eames et al.
6337754 January 8, 2002 Imajo
6353600 March 5, 2002 Schwartz et al.
6362908 March 26, 2002 Kimbrough et al.
6373887 April 16, 2002 Aiyagari et al.
6374124 April 16, 2002 Slabinski
6377640 April 23, 2002 Trans
6421009 July 16, 2002 Suprunov
RE37820 August 13, 2002 Scheinert
6459900 October 1, 2002 Scheinert
6466572 October 15, 2002 Ethridge et al.
6480551 November 12, 2002 Ohishi et al.
6484012 November 19, 2002 Nche et al.
6486907 November 26, 2002 Farber et al.
6498936 December 24, 2002 Raith
6501955 December 31, 2002 Durrant et al.
6556551 April 29, 2003 Schwartz
6564057 May 13, 2003 Chun et al.
6567473 May 20, 2003 Tzannes
6574472 June 3, 2003 Scheinert
6594496 July 15, 2003 Schwarz
6667973 December 23, 2003 Gorshe et al.
6674966 January 6, 2004 Koonen
6684058 January 27, 2004 Karacaoglu et al.
6697603 February 24, 2004 Lovinggood et al.
6704545 March 9, 2004 Wala
6729929 May 4, 2004 Sayers et al.
6768745 July 27, 2004 Gorshe et al.
6771933 August 3, 2004 Eng et al.
6785558 August 31, 2004 Stratford et al.
6801767 October 5, 2004 Schwartz et al.
6826163 November 30, 2004 Mani et al.
6826164 November 30, 2004 Mani et al.
6831901 December 14, 2004 Millar
6865390 March 8, 2005 Goss et al.
6907048 June 14, 2005 Treadaway et al.
6917614 July 12, 2005 Laubach et al.
6952181 October 4, 2005 Karr et al.
6963305 November 8, 2005 Knapp
6967966 November 22, 2005 Donohue
7014500 March 21, 2006 Belesimo
7016308 March 21, 2006 Gallagher
7035671 April 25, 2006 Solum
7050786 May 23, 2006 Caci
7103279 September 5, 2006 Koh et al.
7127175 October 24, 2006 Mani et al.
7136624 November 14, 2006 Ofuji et al.
7151940 December 19, 2006 Diao et al.
7162261 January 9, 2007 Yarkosky et al.
7205864 April 17, 2007 Schultz, Jr. et al.
7215651 May 8, 2007 Millar
7286507 October 23, 2007 Oh et al.
7289972 October 30, 2007 Rieser et al.
7313415 December 25, 2007 Wake et al.
7336961 February 26, 2008 Ngan
7356343 April 8, 2008 Feher
20020037054 March 28, 2002 Schurig
20020049061 April 25, 2002 Pinola
20020089958 July 11, 2002 Feder et al.
20020097704 July 25, 2002 Bolgiano et al.
20020128009 September 12, 2002 Boch et al.
20020151278 October 17, 2002 McLain et al.
20020191565 December 19, 2002 Mani et al.
20030162498 August 28, 2003 Rofheart et al.
20030216121 November 20, 2003 Yarkosky
20040001477 January 1, 2004 D'Amico et al.
20040033804 February 19, 2004 Binzel
20040066326 April 8, 2004 Knapp
20040102195 May 27, 2004 Naghian et al.
20040204097 October 14, 2004 Scheinert et al.
20040233877 November 25, 2004 Lee et al.
20040248580 December 9, 2004 Backes et al.
20040258100 December 23, 2004 Jantti et al.
20050143091 June 30, 2005 Shapira et al.
20050148368 July 7, 2005 Scheinert et al.
20050153712 July 14, 2005 Osaka et al.
20050157675 July 21, 2005 Feder et al.
20050176368 August 11, 2005 Young et al.
20050221817 October 6, 2005 Pinola
20050227710 October 13, 2005 Yamashita et al.
20050233710 October 20, 2005 Lakkis et al.
20060025158 February 2, 2006 Leblanc et al.
20060041680 February 23, 2006 Proctor, Jr. et al.
20060072602 April 6, 2006 Achanta
20060094470 May 4, 2006 Wake et al.
20060123053 June 8, 2006 Scannell, Jr.
20060133346 June 22, 2006 Chheda et al.
20060172710 August 3, 2006 Cahana et al.
20060234722 October 19, 2006 Hanebeck et al.
20070099562 May 3, 2007 Karabinis et al.
20080014948 January 17, 2008 Scheinert
20090061766 March 5, 2009 Ding et al.
Foreign Patent Documents
3707244 September 1988 DE
3707244 September 1988 DE
0391597 October 1990 EP
0664621 July 1995 EP
0876073 November 1998 EP
2253770 September 1992 GB
2289198 November 1995 GB
2315959 February 1998 GB
2320653 June 1998 GB
9115927 October 1991 WO
9533350 December 1995 WO
9628946 September 1996 WO
9716000 May 1997 WO
9732442 September 1997 WO
9824256 June 1998 WO
9937035 July 1999 WO
0174013 October 2001 WO
0174100 October 2001 WO
0217669 February 2002 WO
02059638 August 2002 WO
02087275 October 2002 WO
2004034508 April 2004 WO
Other references
  • U.S. Patent and Trademark Office, “Advisory Action”, “from U.S. Appl. No. 11/728,123”, Apr. 7, 2011, pp. 1-3, Published in: US.
  • U.S. Patent and Trademark Office, “Final Office Action”, “from U.S. Appl. No. 11/728,123”, May 25, 2010, pp. 1-31, Published in: US.
  • U.S. Patent and Trademark Office, “Final Office Action”, “from U.S. Appl. No. 11/728,123”, Jan. 18, 2011, pp. 1-22, Published in: US.
  • U.S. Patent and Trademark Office, “Notice of Allowance”, “from U.S. Patent and Trademark Office”, May 18, 2011, pp. 1-10, Published in: US.
  • U.S. Patent and Trademark Office, “Office Action”, “from U.S. Appl. No. 11/728,123”, Oct. 30, 2009, pp. 1-55, Published in: US.
  • U.S. Patent and Trademark Office, “Office Action”, “from U.S. Appl. No. 11/728,123”, Aug. 30, 2010, pp. 1-19, Published in: US.
  • U.S. Patent and Trademark Office, “International Search Report”, “from PCT Counterpart of U.S. Appl. No. 11/728,123”, Apr. 3, 2008, pp. 1-11, Published in: WO.
  • Djuknic, G.M. and R.E. Richton, “Geolocation and Assisted GPS”, “IEEE Computer”, Feb. 2001, pp. 123-125, vol. 34, No. 2, Publisher: IEEE.
  • “Mulitple-Input Multiple-Output Communications”, “http://en.wikipedia.org/wiki/Multiple-inputmultiple-ouputcommunications”, May 17, 2007, Publisher: Wikipedia, Published in: US.
  • Nakatsugawa et al., “Software Radio Base and Personal Stations for Cellular/PCS Systems”, 2000, pp. 617-621, Publisher: IEEE.
  • B. Schweber, “Maintaining Cellular Connectivity Indoors Demands Sophisticated Design”, “EDN Magazine”, Dec. 21, 2000, pp. 46-50.
  • “Tektronix Synchronous Optical Network (SONET)”, “http://www.iec.org/online/tutorials/sonet/topic03.html”, Aug. 28, 2002, Publisher: International Engineering Consortium.
  • Schwartz, “U.S. Appl. No. 09/560,656”, “Adaptive Capacity Management in a Centralized Basestation Architecture”, filed on Apr. 27, 2000, Publisher: Abandoned, Published in: US.
  • Sabat Jr. , “U.S. Appl. No. 10/352,373”, “Method and Apparatus for Auxiliary Pilot Signal for Mobile Phone Location”, filed Jan. 27, 2003, Publisher: Abandoned, Published in: US.
  • Wala, “A New Microcell Architecture Using Digital Optical Transport”, “Freedom Through Wireless Technogolgy”, May 18, 1993, pp. 585-588, Publisher: Proceedings of the Vehicular Technology Conference, New York, IEEE, Published in: US.
  • International Searching Authority, “International Search Report”, Apr. 3, 2008, Published in: WO.
  • “Edge Introduction of High-Speed Data in GSM/GPSR Networks”, 2003, pp. 1-16, Publisher: Ericsson AB.
  • “Products: nanGSM Picocell”, “http://www.ipaccess.com/nanGSM/nanGSM.htm”, Aug. 2, 2007, pp. 1-8, Publisher: ip.access.
  • Hewlett-Packard Development Co., L.P., “Voice Over Wireless LAN Solution Brief”, “ProCurve Networking by H.P.”, 2006, Publisher: Hewlett-Packard Development Co., L.P.
  • Wala, “A New Microcell Architecture Using Digital Optical Transport”, “Proceedings of the Vehicle Technology Conference”, May 18, 1993, pp. 585-588, Publisher, IEEE, Published in: US.
  • Akos et al., “Direct Bandpass Sampling of Multiple Distinct RF Signals”, Jul. 1, 1999, pp. 983-988, vol. 47, Publisher: IEEE Transactions on Communications.
  • Foxcom Wireless Properietary Information, “Litenna In-Building RF Distribution System”, 1998, pp. 1-8.
  • 1998 Foxcom Wireless Proprietary Information, “Application Note “RFiber—RF Fiberoptic Links for Wireless Applications””, 1998, pp. 3-11, Published in: US.
  • Georges et al., “U.S. Appl. No. 08/635,368”, “Distribution of Radio-Frequency Signals Through Low Bandwidth Infrastructures”, filed Apr. 19, 1996, publisher: Abandoned, Published in: US.
  • Wong et al., “U.S. Appl. No. 09/561,372”, “A Cellular Communications System With Centralized Capacity Resources Using DWDM Fiber Optic Backbone”, filed Apr. 28, 2000, Publisher: Abandoned, Published in: US.
  • Eng et al., “U.S. Appl. No. 09/809,756”, “Wireless Location Positioning Using a Distributed Antenna Architecture”, filed Mar. 14, 2001, Publisher: Abandoned, Published in: US.
  • Osaka et al., “U.S. Appl. No. 10/754,279”, “Method and System for Determining Mobile Unit Location by Aggregation of Tagged Signals From a Distributed Antenna System”, filed Jan. 8, 2004, Publisher: Abandoned, Published in: US.
Patent History
Patent number: RE45505
Type: Grant
Filed: Aug 23, 2013
Date of Patent: May 5, 2015
Assignee: ADC Telecommunications, Inc. (Berwyn, PA)
Inventors: Stefan Scheinert (San Jose, CA), Peter Walther (Milpitas, CA)
Primary Examiner: Khalid Shaheed
Application Number: 13/974,255