JP2003531554A - Method and apparatus for radio frequency coverage of an enclosed area - Google Patents

Abstract

(57) Abstract: Placing a first plurality of slave transceivers (26) inside a region normally enclosed against electromagnetic radiation from an external source to the region, and a first plurality inside the region. A method for wireless communication comprising placing a second plurality of slave transceivers (28) at locations that are spatially separated from and spatially independent of the locations of the slave transceivers (26) of the second. The method further comprises receiving a radio frequency (RF) signal generated within the region at the first and second plurality of slave transceivers (26, 28), and responsive to the first and second slave signals, respectively. Generating, delaying the second slave signal, communicating the first and delayed second slave signals to one or more transceiver base stations (BTS) outside the region, and The method further includes jointly processing the first and second slave signals transmitted to the one or more BTSs so as to reproduce information included in the RF signal generated inside the region.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD OF THE INVENTION

FIELD OF THE INVENTION The present invention relates generally to wireless communications, and more particularly to wireless communications from within areas normally closed to electromagnetic radiation.

[0002]

[Prior art]

Within cellular communication systems, there are typically areas of difficult or inadequate coverage, such as, for example, inside metal frame structures and underground. Methods for improving coverage in areas such as these are well known in the art.

[0003] Charas et al., The disclosure of which is incorporated herein by reference.
et al. U.S. Pat. No. 5,404,570 is closed to a transceiver base station (BTS) capable of receiving signals and transmission from the BTS.
d off) A repeater system for use with closed environments such as tunnels has been described. This system down-converts a high radio frequency (RF) signal from a BTS into an intermediate frequency (IF) signal, which is then radiated by a cable and antenna to a receiver therein in a closed environment. This receiver converts the IF signal to the original R
Up-convert to F signal. Otherwise blocked from BTS (be cu
The system described in this disclosure includes a vehicle moving in a tunnel so that passengers in the vehicle can receive the signal.

Kalanda et al. (Kallan), the disclosure of which is incorporated herein by reference.
dar et al. ), US Pat. No. 5,603,080, discloses multiple BTSs.
And a repeater system used between a closed environment that is closed to transmissions from the BTS. Each system has an R from its respective BTS
The F signal is downconverted to an IF signal and then transferred by a cable in a closed environment to one or more respective receivers therein. Each receiver upconverts the IF signal to the original RF signal. The system described within this disclosure includes vehicles moving between overlapping areas within a tunnel, each area being covered by one of the BTSs via its repeater system. Like this one
Passengers in the vehicle that are shielded from one or more BTSs can receive signals from at least one BTS throughout the tunnel.

[0005] Georgs et al. (Georg), the disclosures of which are incorporated herein by reference.
es et al. US Pat. No. 5,765,099 to stranded wire pair (tw).
Systems and methods have been described for transferring RF signals between two or more regions using low bandwidth media such as isted pair cabling. In the first region, the RF signal is mixed with the first local oscillator to produce a down-converted IF signal. The IF signal is transferred through the low bandwidth medium to the second region where the signal is upconverted to the original RF signal using the second local oscillator. The local oscillators are each locked by a phase locked loop (PLL) in each region to generate the same frequency, and locking causes the local oscillator frequency to be a single low frequency stable reference signal generated in one region. It is executed in each loop by comparing. The reference signal is transferred between regions via a low bandwidth medium.

[0006] Dean et al., The disclosure of which is incorporated herein by reference.
t al. U.S. Pat. No. 5,513,176 describes a distributed antenna array in areas where reception is difficult. The performance of this antenna array is enhanced by creating signal diversity within the array. Each antenna in the array has a different time delay applied to the signal it receives, thus producing received signal diversity. The different delayed signals are preferably down-converted to an intermediate frequency and then transferred via cable over that area.

[0007] Wright et al., The disclosure of which is incorporated herein by reference.
t al. U.S. Pat. No. 5,930,293 describes a wireless repeater with first and second spatially separated antennas. Both antennas receive the signal from the transmitter and the signal received by the second antenna has a time delay added to the original signal. The two signals are summed to form one aggregated signal transmitted from the third antenna. The aggregate signal receiver is capable of reconstructing the signals received by the first and second antennas.

[0008]

[Means for Solving the Problems]

It is in accordance with some aspects of the present invention to provide improved methods and apparatus for the transmission of radio frequency signals within a region normally closed to electromagnetic radiation.
One purpose.

In a preferred embodiment of the present invention, a group of fixed transceivers, herein referred to as slave units, is used in an area normally closed to electromagnetic radiation from outside that area, such as inside a building. Is installed in. In the area, slave units receive radio frequency (RF) signals from at least one mobile transceiver, such as a mobile cellular telephone. The group of slave units is usually divided into first and second subgroups having an equal number of fixed transceivers in each subgroup.

The slave units of the first subgroup are spatially separated from the slave units of the second subgroup. Apart from being spatially separated, the transceivers in the first subgroup are arranged independently of the transceivers in the second subgroup. The spatial separation is at least sufficient so that from one transmission of the at least one mobile transceiver the signals received by the first subgroup and the signals received by the second subgroup can be distinguished. Most preferred. Signals are typically distinguishable in terms of amplitude, or phase, or arrival time, or a combination of these or other representations of signal parameters. Thus, one of the plural
One slave unit may act as a diversity receiver with respect to the other subgroup of slave units acting as the main receiver.

R received by the slave unit from at least one mobile transceiver
The F signal is downconverted to an intermediate frequency (IF) signal and then transferred from that area by one or more cables. The IF signal from the slave unit of each sub-group is transferred to the master unit that up-converts the IF signal to reproduce the information contained in the corresponding RF signal. In one of the subgroups, a time delay is introduced in the IF signal, which time delay is transferred to the corresponding regenerated RF signal. The delayed and non-delayed IF signals are combined in a splitter / combiner and its combined IF consisting of the main and delayed diversity signals.
The signal is upconverted to a combined RF signal. The combined RF signal is transmitted to a transceiver base station (BTS), which demodulates and reproduces the information contained in the combined RF signal.

[0012] Thus, the single time delay introduced in the diversity signal causes a typical code division multiple access (CDMA) rake receiver to detect the information contained in the combined main and diversity signals. Enables demodulation and playback. Unlike the methods well known in the art, the method of the present invention is such that the optimal signal is recovered from the main and diversity signals generated inside the enclosed area and received by spatially independent transceivers. Is possible.

In one preferred embodiment of the invention, the IF signal is transferred to the slave units of the first and second subgroups and a delay is added to the IF signal transferred to one of the subgroups. The IF signal is upconverted to an RF signal in the slave unit, and an RF signal consisting of delayed and undelayed RF signals is emitted from that unit. Each of the one or more mobile transceivers receives both signals. Due to the time delay introduced on one of the signals, each of the mobile transceivers
Both signals are received as a composite signal consisting of the information contained in the first signal and the second delayed signal. Most preferably, the information is demodulated and regenerated by each of the mobile transceivers, where it is used in separate or combined form, resulting in an overall improvement in signal reception.

Preferably, the RF signals are direct spread spectrum modulated signals, where each signal consists of multiple chips. While one preferred embodiment of the present invention uses a CDMA system, another preferred embodiment of the present invention is a non-CDMA system, such as a GSM system with an equalizer capable of tolerating certain signal delays. It will be appreciated that using the system.

Accordingly, there is provided, according to a preferred embodiment of the present invention, a method for wireless communication, including the following: of a region normally shielded against electromagnetic radiation from an external source to that region. Arranging a first plurality of slave transceivers therein; arranging a second plurality of slave transceivers in positions spatially separated from the positions of the first plurality of slave transceivers and spatially independent within the area Locating; first and second slave signals receiving radio frequency (RF) signals generated within the area at the first plurality of slave transceivers and the second plurality of slave transceivers, and responding thereto, respectively. Delaying the second slave signal; the first and delayed second slave signals one or more outside the region A first and second slaves transmitted to one or more BTSs to reproduce the information contained in the RF signal generated inside the area; and to the above transceiver base station (BTS); Process signals jointly.

Preferably, transmitting the first and second slave signals comprises regenerating a master RF signal from the first slave signal and regenerating a diversity RF signal from the second slave signal, And co-processing the first and second slave signals includes regenerating an optimal RF signal from the regenerated master RF signal and the regenerated diversity RF signal.

Preferably, disposing the second plurality of slave transceivers allows the RF signal received by the second plurality of slave transceivers to be distinguished from the RF signal received by the first plurality of slave transceivers. Including placing at least one of the second plurality of slave transceivers at a distance that is sufficiently separated from the first plurality of slave transceivers.

Preferably, delaying the second slave signal causes a single time delay to the second.
Including applying to the slave signal of.

There is further provided, according to a preferred embodiment of the present invention, an apparatus for wireless communication, including the following: a first and a second plurality of slave transceivers generally shielded against electromagnetic radiation. The first and second plurality of slave transceivers are spatially separated from each other within the area and spatially independent of each other, and the plurality of slave transceivers are
RF) signal and generates respective first and second slave signals in response to the RF signal; a first plurality of slave transceivers and a second plurality of slave transceivers; A delay generator connected for delaying with respect to one slave signal; and receiving and converting the first signal and the delayed second slave signal, and RF
The first and second transformed signals are respectively outside the region so that the information contained in the signal is reproduced by jointly processing the first and second transformed signals received by the BTS. One or more transceiver base stations (BTS
), The master unit.

Preferably, at least one of the first plurality of slave transceivers is such that the RF signal received by the second plurality of slave transceivers is distinguishable from the RF signal received by the first plurality of slave transceivers. Are sufficiently spatially separated from the second plurality of slave transceivers.

The delay generator preferably delays the second slave signal by applying a single time delay.

There is further provided, according to a preferred embodiment of the present invention, a method for wireless communication within an area normally shielded against electromagnetic radiation from an external source to the area, including: Receiving a radio frequency (RF) signal transmitted from outside the region at a master transceiver unit and generating first and second master signals in response thereto; a first plurality of slave transceivers at the region. Locating the second plurality of slave transceivers in a location spatially separated from the location of the first plurality of slave transceivers within the area; arranging the first master signal in the first plurality. A first slave signal in response to the second slave signal and delaying the second master signal; 2 to multiple slave transceivers,
Generating a second slave signal in response thereto; transmitting the first and second slave signals to a mobile transceiver unit within the area; and a mobile transceiver to reproduce the information contained in the RF signal therein. Jointly process the first and second slave signals transmitted to the.

Positioning the second plurality of slave transceivers preferably includes positioning the second plurality of slave transceivers in a position that is spatially independent of the position of the first plurality of slave transceivers.

There is further provided according to a preferred embodiment of the present invention an apparatus for wireless communication, including the following: Radio frequency (RF) generated outside the area normally confined to electromagnetic radiation. )
A master unit for receiving the signal and converting the RF signal into first and second master signals; connected to delay the second master signal with respect to the first master signal,
A delay generator; and a first plurality of slave transceivers and a second plurality of slave transceivers in which the first and second plurality of slave transceivers are spatially separated from each other within the region; the first and second slave transceivers. Of the plurality of slave transceivers of the first and second delayed master signals respectively receive the first and second delayed master signals.
Converting the first and second converted signals received by the mobile transceiver unit so that the information contained in the RF signal is recovered by co-processing the first and second converted signals. The second transformed signal is transmitted to each mobile transceiver unit within the area.

The first and second plurality of slave transceivers are preferably spatially independent of each other.

[0026]

DETAILED DESCRIPTION OF THE INVENTION

The invention will be more fully understood from the following detailed description of preferred embodiments thereof, taken together with the drawings.

Now, according to a preferred embodiment of the present invention, in-buildi
ng) Reference is made to FIG. 1, which is a circuit block diagram illustrating a coverage system 10.
The building 30 is substantially shielded from electromagnetic radiation from an external transceiver base station (BTS) 12 to the building. A mobile transceiver 36 inside the building, such as an industry standard mobile phone, emits a radio frequency (RF) signal of the type received by the BTS 12. Preferably, the RF signal emitted by the mobile transceiver 36, also referred to herein as the mobile RF transmit signal, is a code operating at industry standard chip rates, although the principles of the present invention are applicable to other encoding and transmitting circuits. It is a division multiple access (CDMA) signal.

The first sub-group of slave transceivers 26, also referred to herein as main slave transceivers, and the second sub-group of slave transceivers 28, also referred to herein as diversity slave transceivers, include building 3
It is placed in 0. Most preferably, the main slave transceivers 26 are star connected by one or more active splitter / combiners 39. Instead, the slave transceiver 26 is daisy chained.
chain) or a hybrid star daisy chain. Similarly, most preferably, diversity slave transceivers 28 are star connected by one or more active splitter / combiners 43. Instead, the slave transceivers 28 are connected in a daisy chain or a hybrid star daisy chain.

Slave transceiver 26 is spatially separated from slave transceiver 28, while all slave transceivers are substantially the same in configuration and operation. For a detailed description of the operation and configuration of suitable slave transceivers, see "In-Building Radio Frequency Coverage".
is given to a U.S. patent application, filed October 29, 1999, entitled "recovery Coverage", which is assigned to the assignee of the present invention, the disclosure of which is incorporated herein by reference. When the transceiver 36 transmits, the RF signal received by the sub-group slave transceiver 26 is sufficiently spatially separated so that it can be distinguished from the RF signal received by the sub-group slave transceiver 28, eg, received. The filtered signals may differ in amplitude, or phase, or arrival time, or a combination of these or other signal parameters, thus the main slave transceiver 26 receives the RF signal from the mobile transceiver 36 as the main RF signal. Receive and diversity slave transceiver 28 receives the RF signal as a diversity RF signal from the transceiver 36. Apart from being spatially separated as described above, there is no relationship between the placement of the main slave transceiver and the diversity slave transceiver, so Slave transceiver 26 is spatially independent of diversity slave transceiver 28.

The slave transceivers 26 and 28 operate by mixing the received RF signal with a local oscillator signal, and thus, as is well known in the art, the received RF signal may be intermediate frequency (IF). ) Downconvert to signal. The IF signal from the main slave transceiver 26 is transmitted from the building 30 to the combiner 27 via one splitter / combiner 39 and the cable 21. The IF signal from the diversity slave transceiver 28 is from the building 30-1
It is transmitted to the combiner 27 via the one splitter / combiner 43 and the cable 23. In the course of the cable 23 there is a delay unit 24, most preferably formed of a surface acoustic wave filter acting as a delay generator. instead of,
Delay unit 24 may be any standard delay unit capable of adding a single time delay to the IF signal transmitted from diversity slave transceiver 28. Most preferably, the delay added by the delay unit 24 is
At least twice the chip period of the modulated RF signal transmitted by the transceiver 36.

Combiner 27 combines the IF signal from main slave transceiver 26 and the delayed IF signal from diversity slave transceiver 28. The combined IF signal is transferred to the up converter 29 in the master transceiver unit 22. In the upconverter 29, the combined IF signal is most preferably provided in the master unit 22 for reproducing the RF signal received by the main slave transceiver 26 and the diversity slave transceiver 28 as a combined RF signal. Is mixed with the local oscillator (LO) signal generated by the local oscillator 31. A detailed description of the operation and construction of a suitable master transceiver unit is given in the aforementioned US patent application.

The combined RF signal is then transmitted to the BTS 12 via the duplexer 14. Preferably, the BTS 12 is connected to the master unit 2 by a direct cable connection 47.
Connected to 2. Instead, the cable connection 47 consists of a transmit and / or receive cable connecting the BTS 12 to the master unit 22 without the duplexer 14. Further alternatively, the BTS 12 and the master unit 22 are connected by wireless connection. In one preferred embodiment of the present invention, BTS 12 includes a master unit 22, which saves component cost.

The BTS 12 thus receives a composite signal containing a first component representing the main signal and a second component representing the delayed diversity signal. It will be appreciated that the information contained in the composite signal can be demodulated and reproduced in an industry standard CDMA rake receiver.

The duplexer 14 includes a BTS 12 also referred to herein as a BTS RF transmit signal.
The RF signal transmitted from the master unit 22 is received, and this signal is also transferred to the down converter 33 included in the master unit 22. Downconverter 33 preferably uses the signal from local oscillator 31 to generate the IF transmit signal. The IF transmission signal is forwarded to splitter 35, which splits the transmitted IF signal into first and second IF signals.
Of the IF signal of substantially the same. The first IF signal goes to the active splitter 39 and then from this splitter to the transceiver 2
6 to the BTS RF transmit signal where it is regenerated by up-conversion. Methods for down-conversion and up-conversion of the transmitted RF signal from the BTS as described above are well known in the art, and a detailed description of one such method is within the aforementioned US patent application. Also given to.

The second IF signal is transferred to the active splitter 43 via the cable 41. In the course of the cable 41 there is a delay unit 45, which is most preferably implemented as described above for the delay unit 24. Delay unit 45 most preferably produces a delay of the same order of magnitude as that produced by delay unit 24. The delayed IF signal is transferred from active splitter 43 to slave transceiver 28, where the delayed BTS RF transmit signal is regenerated by upconversion.

The mobile transceiver 36 uses the regenerated BTS transmitted from the transceiver 26.
It receives both the RF signal and the recovered delayed BTS RF signal transmitted from transceiver 28. The BTS RF signal and the delayed BTS RF signal are then sent to the optimum RTS transmitted from BTS 12 using methods well known in the art.
Used to obtain the F signal. For example, if the RF signal is a CDMA pilot RF signal generated by the BTS to track the mobile transceiver, the mobile transceiver 36 demodulates by checking for strong multipath arrivals with the searcher contained within that transceiver. Thus, the pilot signal can be reproduced. Alternatively, the optimum signal can be reproduced by a non-CDMA system that can tolerate delays of the sizes mentioned above.

It will be appreciated that the preferred embodiments described above are demonstrated by way of illustration and that the invention is not limited to what has been shown and described in detail above. Rather, the scope of the invention is set forth herein above of course as to variations and modifications that will occur to those skilled in the art upon reading the foregoing description and that are not disclosed in the prior art. It includes both associative and semi-associative of various features.

[Brief description of drawings]

FIG. 1 is a circuit block diagram illustrating an in-building coverage system according to a preferred embodiment of the present invention.

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Claims (11)

[Claims] 1. A method for wireless communication, comprising: arranging a first plurality of slave transceivers within an area normally shielded against electromagnetic radiation from an external source to the area; Spatially separating the location of the first plurality of slave transceivers within a region and arranging the second plurality of slave transceivers in spatially independent locations; the first plurality of slave transceivers and the first plurality of slave transceivers. Two plurality of slave transceivers receive a radio frequency (RF) signal generated within the region and generate corresponding first and second slave signals respectively; delay the second slave signal Transmitting the first and delayed second slave signals to one or more transceiver base stations (BTS) outside the region; and To reproduce the information contained in the RF signal generated internally, 1
Jointly processing the first and second slave signals delivered to one or more BTSs. 2. Transmitting the first and second slave signals comprises regenerating a master RF signal from the first slave signal and regenerating a diversity RF signal from the second slave signal. Comprising, co-processing the first and second slave signals comprises regenerating an optimal RF signal from the regenerated master RF signal and the regenerated diversity RF signal. The method described in 1. 3. Placing the second plurality of slave transceivers comprises:
At least one of the second plurality of slave transceivers is configured such that the RF signal received by the second plurality of slave transceivers is distinguishable from the RF signal received by the first plurality of slave transceivers. The method of claim 1, comprising placing at a sufficient distance from one of the plurality of slave transceivers. 4. The method of claim 1, wherein delaying the second slave signal comprises applying a single time delay to the second slave signal. 5. An apparatus for wireless communication comprising: a first and a second plurality of slave transceivers spatially separated from each other within a region normally shielded against electromagnetic radiation, Spatially independent and the first and second plurality of slave transceivers receive a radio frequency (RF) signal generated within the area and are responsive to respective first and first slave signals in response to the RF signal. Two
A first plurality of slave transceivers and a second plurality of slave transceivers for generating a slave signal; a delay generator connected to delay the second slave signal with respect to the first slave signal; Receiving and converting a first signal and the delayed second slave signal;
The respective first and second transformed signals are reproduced such that the information contained in the F signal is reproduced by jointly processing the first and second transformed signals received by the BTS. A master unit that communicates to one or more transceiver base stations (BTS) outside the area. 6. The first plurality of slave transceivers so that the RF signal received by the second plurality of slave transceivers can be distinguished from the RF signal received by the first plurality of slave transceivers. 6. At least one of the plurality of slave transceivers is sufficiently spatially separated from the second plurality of slave transceivers.
The described device. 7. The apparatus of claim 5, wherein the delay generator delays the second slave signal by applying a single time delay. 8. A method for wireless communication within an area normally shielded against electromagnetic radiation from an external source to the area, comprising: a radio frequency transmitted from outside the area ( RF) signal at a master transceiver unit and generating corresponding first and second master signals; arranging a first plurality of slave transceivers within the region; a second plurality of slave transceivers A location spatially separated from a location of the first plurality of slave transceivers within the area; transmitting the first master signal to the first plurality of slave transceivers and responsive thereto. Generating a slave signal of 1; delaying the second master signal; transmitting the delayed second master signal to the second plurality of slave transceivers and responsive thereto A second slave signal for transmitting the first and second slave signals to a mobile transceiver unit within the area; and the mobile transceiver for reproducing the information contained in the RF signal therein. Jointly process the first and second slave signals transmitted to the. 9. Placing the second plurality of slave transceivers comprises:
9. The method according to claim 8, comprising arranging the second plurality of slave transceivers in locations spatially independent of the locations of the first plurality of slave transceivers. 10. An apparatus for wireless communication, comprising: a radio frequency (RF) generated outside an area normally enclosed to electromagnetic radiation.
A master unit for receiving a signal and converting the RF signal into first and second master signals; a delay generator connected to delay the second master signal with respect to the first master signal The first and second plurality of slave transceivers are spatially separated from each other within the region; and the first and second plurality of slave transceivers; A slave transceiver receives the first and the second delayed master signals, respectively, and converts the first and second converted signals into first and second converted signals, the first and second received signals being received by a mobile transceiver unit. The first and second converted signals are combined so that the information contained in the RF signal is reproduced by jointly processing the two converted signals. Respectively transmitted to the interior of the mobile transceiver unit of frequency. 11. The apparatus of claim 10, wherein the first and second plurality of slave transceivers are spatially independent of each other.