GB2440383A

GB2440383A - Enhancing mobile network coverage within buildings using television aerials to carry radio/mobile signals in

Info

Publication number: GB2440383A
Application number: GB0617432A
Authority: GB
Inventors: Alan Law; Chami Youssef; Toby Kier Proctor
Original assignee: Vodafone Group PLC
Current assignee: Vodafone Group PLC
Priority date: 2006-07-21
Filing date: 2006-09-05
Publication date: 2008-01-30
Anticipated expiration: 2026-09-05
Also published as: GB2440383B; GB0617432D0

Abstract

A system for distributing signals from a mobile network, comprising means for receiving mobile network signals and television signals, means for inserting the received signals into a signal carrying means, a filter for extracting the mobile network signals from the signal carrying means, and means for transmitting the extracted signals. The invention aims to penetrate buildings with mobile network signals by making use of, for example, television aerials to carry them into buildings.

Description

Residential Repeaters The present invention relates to an apparatus for

enhancing mobile network coverage and, in particular, to enhancing network coverage within buildings.

Indoor coverage of high frequency mobile networks, for example GSM (downlink signals in the range 1805 -1880 MHz) and UMTS (downlink signals in the range 2110 -2170 MHz) is difficult to provide due to the high penetration losses associated with such high frequency signals. Such signals must be high power in order to penetrate through the walls and other boundaries of buildings. Therefore, many signals which emanate from base stations are too weak to penetrate the building and so cannot be received inside the building. However, although they are not strong enough to penetrate the building, they are strong enough to be picked up by devices located immediately outside the IS building.

Typically, mobile network coverage within buildings is provided by increasing the density of the deployed base stations in order that the signal strength at any point is increased and so that the signals are significantly powerful to penetrate the building. However, this is a very expensive solution due to the significant costs of installing new bases stations and providing high power signals. Alternative solutions include boosting the signal into the building by using a dedicated repeater. However, existing repeaters are too expensive to make this a cost effective means to improve coverage in all buildings.

Additionally, the repeater antennas would be sited outside the building, in order that they can receive the signal from the main base station, to provide coverage inside. This requires that the signal is retransmitted at high amplitude in order that it can penetrate the building. Since the cost of transmitting radio signals increases as the power increases, this is a very cost inefficient process since expensive, high power, signals are used merely to penetrate a building in which most of the power is lost when penetrating the boundary. In certain cases, the network signal can be wired into a base station located in the building however this is impractical on a large and domestic scale since the network would have to provide a hardwired network cable into every building.

We have appreciated that customers require network coverage when they are located inside buildings. However, providing this coverage by increasing the number of base stations, providing high power transmitters or by providing a hard wired base station in every building is expensive and is an inefficient solution.

Embodiments of the present invention address the problem of penetrating buildings with mobile network signals by making use of, for example, television aerials, which exist On most buildings, to receive network signals and to carry those signals into the building using existing cabling. The network signals are then filtered from the cable and transmitted inside the building using a low power transmitter. Such embodiments are able to carry signals into the building which would not be sufficiently strong to penetrate the walls of boundaries of the buildings. The wide scale implementation of embodiments of the invention would reduce the requirement for signals to be at a high power at boundaries of buildings in order that they are able to penetrate the building. This would reduce the requirement for additional base stations in many built up areas as well as reducing the need for high power signal transmissions. This would greatly reduce the costs for network providers.

The invention is defined in its various aspects in the claims, to which reference should now be made.

A specific embodiment of the invention is now described with reference to the accompanying drawings in which: Figure 1 shows a building incorporating an embodiment of the invention.

Figure 2 is a diagram showing a filter used in an embodiment of the invention.

Figure 1 shows a first embodiment of the invention incorporated into a building 100 having a typical television aerial 110. Typically, the aerial will be designed to receive signals at typical television signal frequencies of around 850 MHz. However, the aerial will also automatically pick up radio network signals at a higher frequency from, for example, mobile network base stations 120. The aerial 110 is connected to the television cabling 130 inside the building and signals received by the aerial are carried down the cable and into the building.

Once the signals are inside the building, a filter 140 is used to separate the high frequency mobile transmission signals from the television signals. The filter is set to extract signals in the mobile phone frequency range. Typically, the filter should extract GSM and UMTS signals in the frequency range of between around 1700 MHz and 2200 MHz. Such filters will not affect the television signals which are typically around 850 MHz. The filtered signals may then be amplified before being carried to an antenna 150 inside the building. The signals are then transmitted within the building.

Figure 2 is a diagram of a filter used in an embodiment of the invention. The combined television and mobile network signal is received by the aerial outside a building and carried into the building via input cable 200. The cable is directed into filter 210. The filter is set to extract signals in the mobile network frequency range and the filtered mobile signal is input into cable 220 and transmitted by antenna 230. Any signals outside the frequency range of the filter pass through the filter and are unaffected. These signals are carried onwards to the television set. In prelerred embodiments of the invention the filter is a passive filter.

Typically, the transmission antenna inside the building should be a repeater which transmits all incoming signals. However, in certain embodiments the repeater could be tuned to transmit only signals within specific frequency ranges, for example the carrier frequency associated with a particular network operator.

Embodiments of the invention are most conveniently inserted at the connection point between cables or at the connection between the cable and the television. In preferred embodiments of the invention the filter and transmitter arrangement is incorporated into devices which connect to the cabling, for example set top boxes or televisions.

The repeater could transmit the mobile network signals directly or, alternatively, could convert the signals onto a sort range radio wavelength and transmit these to a further antenna which converts them back to mobile network frequency before transmission.

Such embodiments would enable a customer to move the indoor transmitter to a convenient location within his house or office without being restricted to positioning the antenna at the physical location of the connection between cables or cables and the television. The transmission antenna should be located in a position in which it does not experience significant interference from signals which are received from other base stations and repeaters located outside the building.

The most basic embodiments of the invention are only concerned with downlink (i.e. base station to handset) signals and include a filter and transmitter. Further embodiments of the invention may also improve the propagation of uplink signals (i.e. mobile communication device to base station). Such embodiments include a receiver 250 to pick up signals from mobile communication devices within the building. Those signals are then mixed into the cabling and carried out of the building to the antenna.

io The signals should be mixed into the cable on the aerial side of filter in order that they are not required to pass back through the filter. Such embodiments would also require a further filter, to extract the mobile communication signals, connected to a transmitter outside the building which transmits the signals back to the network.

Television aerials are inherently directional and so, if the existing antenna does not provide the required signal level due to its orientation, additional antennas could be installed using the same pole.

Embodiments of the invention provide the advantage that mobile network coverage is provided within buildings without the signal having to pass through walls or other boundaries. Instead, any signal which can be received outside the building is received by an existing aerial and is carried into the building via, preferably, existing cabling.

Such embodiments allow signals to penetrate buildings which, otherwise, would be too weak to pass through the walls. It will be clear to those skilled in the art that, if embodiments of the invention were used on a wide scale, mobile network suppliers could greatly reduce their costs by transmitting at lower signal strengths since their signals do not need to penetrate through buildings.

Additionally, embodiments of the invention provide significant gains to signal strength within buildings, and are able to do so relatively cheaply due to only needing a single filter and antenna in the system and by making use of the television aerial as the donor antenna.

Claims

Claims 1. A system for distributing signals from a mobile network,

comprising: means for receiving mobile network signals and television signals; means for inserting the received signals in to a signal carrying means; a filter for extracting the mobile network signals from the signal carrying means; and, means for transmitting the extracted signals.

2. A system according to claim 1 wherein the mobile network signals are within the frequency range 1700 -2200 MHz.

3. A system according to claim 1 or 2 wherein the television signals have a frequency around 850 MHz 4. A system according to claim 1, 2 or 3 wherein the means for receiving signals is located outside a building and the means for transmitting the filtered signals is located inside the building.

5. A system according to claim 4 wherein the signal carrying means carries the signals from the receiving means into the building.

6. A system according to claim 1, 2, 3, 4 or 5 wherein the means for receiving the mobile network signals and the television signals is a television aerial.

7. A system according to claim 1, 2, 3, 4, 5 or 6 wherein the means for carrying the received signals is a television cable.

8. A system according to any of claims 1 to 7 wherein the filter is a passive filter.

9. A system according to any of claims 1 to 8 further comprising means for receiving signals from a mobile communication device within a building and means for inserting the signal into the carrying means.

10. An apparatus for filtering mobile network signals from a cable carrying mobile network signals and television signals, comprising: a filter to extract signals of frequency between 1700 -2200 MHz from a cable carrying mobile network signals and television signals; means for transmitting the extracted signals.

11. A method for distributing signals from a mobile network compnsing the steps of: receiving mobile network signals and television signals; inserting the signals into a signal carrying means; extracting the mobile network signals from the carrying means; and, transmitting the extracted signals.

12. A method according to claim 11 wherein the mobile network signals are in the frequency range between 1700 -2200 MHz.

13. A method according to claim 11 or 12 wherein the television signals have a frequency around 850 MHz.

14. A method according to claim 11, 12 or 13 wherein the signals are received outside a building and the extracted signals are transmitted inside the building.

15. A method according to claim 14 wherein the means for carrying the received signals carries the signals from the receiving means into the building.

16. A method according to claim 11, 12, 13, 14 or 15 wherein the mobile network signals and television signals are received by a television aerial.

17. A method according to claim 11, 12, 13, 14, 15 or 16 wherein the received signals are carried by a television cable.

18. A method according to any of claims 11 to 17 wherein the filter is a passive filter.

19. A method according to any of claims 11 to 18 comprising the further steps of receiving signals from a mobile communication device within a building and inserting the signal into the signal carrying means.

20. A method for extracting mobile network signals from a cable carrying mobile network signals and television signals, comprising the steps of: Extracting mobile network signals having a frequency between 1700-2200 MHz from a cable carrying mobile network signals and television signals, and transmitting the extracted signals. I0

21. An apparatus for distributing signals from a mobile network substantially as herein described with reference to the accompanying figures.

22. A method for distributing signals from a mobile network substantially as herein is described with reference to the accompanying figures.