Base station for a mobile radio system

The invention relates to a radio station for a communication system with a network-side communication connection and with a power supply connection.

Radio stations are stationary radio devices that implement the radio interface to mobile or stationary devices for communication systems, for example mobile communication systems, for example the GSM (global system for mobile communication) mobile radio system or the DECT (digital enhanced cordless telephony) cordless telephony system.

These radio stations are housed in specially designed rooms and containers to connect them to the necessary technical infrastructure. The technical infrastructure includes a power supply, facilities for climate protection, a communication connection and arrangements for antenna devices of the radio station in order to ensure proper radio propagation.

A typical example of this is the accommodation of the radio station in an air-conditioned room into which a power supply, a communications connection and a connection for lightning protection are introduced. The installation of a remote antenna is provided on a roof or a separate mast. For a radio station installed in this way, considerable development and installation costs are necessary.

The invention has for its object to reduce the installation effort for a radio station. This object is achieved by the radio station according to the features of claim 1 or 2. Advantageous further developments can be found in the subclaims.

A radio station for a communication system with a network-side communication connection and with a power supply connection is integrated according to the invention into a housing of a lighting device or an optical signaling device, the lighting device or the optical signaling device containing a light emitter and an external power supply.

Miniaturization of radio stations, see European patent application EP 0 690 641 A2, enables the technical equipment of a radio station to be integrated into smaller housings. A lighting device, such as that of a street lamp, an outdoor lamp, for example in stop areas, or is formed by ceiling lighting in premises, has the advantage that a large part of the technical infrastructure with weather protection and an external power supply is already available in one housing. The same applies to optical signaling devices. Furthermore, these facilities offer the advantage that they serve to illuminate or supply rooms in which a large number of people are present. The installation locations of these facilities thus correspond to the rooms that are particularly to be supplied by a communication system.

The integration of radio stations in existing technical facilities, in contrast to separate assembly, and especially in lighting devices or optical signaling devices has the additional advantage that network operators do not have to open up additional locations for the radio stations if the network is to be compacted . Urban planning requirements for the design and installation of radio stations can also be more easily met if known forms of lighting devices or optical signaling devices, such as traffic lights or illuminated traffic signs, are advantageously used.

The power supply connection of the radio station is advantageously connected to the external power supply. This saves a separate power supply for the radio station.

An antenna device of the radio station is advantageously mounted in such a way that its radiation pattern corresponds to that of the light emitter. The planning of the supply of rooms by lighting devices normally provides for area coverage and continuous, as uniform as possible lighting for heavily used rooms. Exactly this necessity is also present with the radio technical supply eg through a mobile communication system. However, certain rooms can be supplied with more radio technology if a particularly high network load is suspected in them, this corresponds to a headlight effect of lighting devices.

An optical signaling device is also usually provided in places where people are heavily frequented and directs its signaling, implemented by the light emitter, to the rooms with these people. Thus, even in the case of an optical signaling device, there is a correlation between the optical signaling space and the coverage area by the radio station.

According to a further advantageous embodiment of the radio station, it is connected to a device for lightning protection which is already provided for the lighting device or optical signaling device. Lightning protection is a further device for weather protection, which is often already present in these devices and which does not need to be additionally provided when the radio station according to the invention is installed outside of fixed buildings.

According to an advantageous further development, a device for energy storage powered by the power supply is provided, which is available for supplying the radio station when the external power supply is switched off. With the device for energy storage, the power supply of the radio station can be secured during the day even when the external power supply is switched off, for example with an outdoor lighting device, or if the external power supply fails, an emergency power supply is provided to maintain the area coverage of the communication system. The power supply of the radio station becomes more independent of the external power supply. A galvanic isolation of the radio station from the external power supply, which can also be effected by an isolating transformer, also prevents direct effects of interference on the external power supply from impairing the function of the radio station.

A device for cooling the radio station is advantageously thermally coupled to an ascending air flow. An ascending air flow arises, for example, from a chimney effect when warm, lighter air rises near the floor and thus creates an air flow. Openings in the housing of the lighting device are designed in such a way that they receive this air flow and pass devices for cooling the radio station, for example cooling fins, and thus also cooling the radio station.

The communication technology connection of the radio station can of course take place via a fixed line to further network elements of the communication system, however this communication technology connection can also take place via a radio connection which can easily reach the installation site of the lighting device or optical signaling device.

This radio connection can be ensured in particular by means of infrared signals from other such devices or signals in the frequency band of road traffic communication devices. Economical modules are available for infrared connections, which allow a cost-effective installation of the communication connection. If the frequency band is to be used by road traffic communication devices, then there is the advantage in particular in the case of an installation along roads that no additional frequency allocation is necessary.

According to a further advantageous embodiment, the radio station is mounted in a location with free radiation in a direct line to the earth at an installation height of at least 2.5 meters. The free radiation from the antenna device in the direction of the terminal prevents shadowing of the radio signals and makes it possible to keep the transmission energy required to supply a communication link low. The mounting height in particular characterizes the radio area of ​​the radio station, so that a minimum mounting height is advantageous to ensure a sufficient radio area.

Lighting devices, if they are designed as street lamps, are mostly free-standing, so that a device for solar power supply is easy to mount on them. This device for solar power supply helps to reduce the power consumption via an external power supply. The same applies to optical signaling devices.

The radio station according to the invention will be explained in more detail below with reference to the figures using exemplary embodiments. The invention is explained with reference to a base station for a GSM mobile radio system. The radio station according to the invention can also be used as a base station for other mobile radio networks, for DECT cordless communication systems and also as radio stations for wireless subscriber connection (wireless in the local loop), etc - be pronounced both on the network side and on the subscriber side.

It shows<dl id="dl0001"><dt>FIG 1</dt><dd>two radio stations integrated in street lamps,</dd><dt>FIG 2</dt><dd>two variants of a lighting device with an integrated radio station, each in side view (a and d), view from below (b and e) and view from above (c and f),</dd><dt>FIG 3</dt><dd>two radio stations integrated in ceiling lighting devices in a closed room,</dd><dt>FIG 4</dt><dd>a view from below of a radio station integrated in a ceiling lighting device,</dd><dt>FIG 5</dt><dd>a radio station which is integrated in a traffic light, and</dd><dt>FIG 6</dt><dd>a radio station that is integrated into an illuminated traffic sign.</dd></dl>

1 shows two lighting devices in the form of street lamps. Such street lamps are used to illuminate streets, footpaths, pedestrian zones or other rooms with a lot of passenger traffic. These street lamps are mounted on masts at a distance of several meters at a mounting height of more than 3 meters. For details of the installation and planning of lighting systems, see CH Sturm and E. Klein,<img file="EP0840464A1_D0001.tif" />Operating devices and circuits for electric lamps ", Siemens Aktiengesellschaft, Berlin, Munich, 1992, in particular pages 326 to 330.

The lighting device has a housing G and a light emitter L, the lighting device being connected to an external power supply SV and a device for lightning protection B. The power supply is, for example, a 230 volt AC voltage. Lightning protection B of the lighting device is implemented via the mast by earthing at the foot of the mast.

A radio station BS is integrated in the housing G of the lighting device. This base station BS is designed as a micro transceiver station and contains transmitting and receiving devices and devices for organizing and controlling the base station BS. The base station BS is part of a GSM mobile radio system, for example, and supplies one micro cell each. For the internal structure of a base station BS is on<img file="EP0840464A1_D0001.tif" />AirXpress-D900 / D1800 Mobile Network Base Station equipment ", Siemens Aktiengesellschaft from February 1996. For connecting the base station BS to the network, existing cable shafts of the lighting system comprising the lighting device can also be used.

Each base station BS supplies a radio area which overlaps with radio areas of adjacent base stations BS at least in its edge areas. According to the exemplary embodiment, the base station BS provides channels on a carrier frequency or contains only the devices which are absolutely necessary within the GSM mobile radio system for supplying the microcell with radio resources. This enables miniaturization of the base station BS with low transmission powers of 0.01 to 2.5 W. The miniaturization and the reduced power consumption make it possible to integrate the base station BS into the housing G of the lighting device. The simple structure of the base station BS also saves on monitoring, control and maintenance (O&amp;M) of the base station BS.

The catalog <img file="EP0840464A1_D0001.tif" />Outdoor lighting "from Siemens Aktiengesellschaft, February 1, 1993, order number E 20002-K8420-A101-A3 shows exemplary housing shapes for the integration of a base station BS into the housing G. The housing G of the lighting device can be opened, so that easy access to it Plug-in modules of the base station BS is possible.

According to FIG. 2a, the power supply SV and the communication connection KA take place via the mast approach, the mast approach also leading the device for lightning protection B. The power supply connection SA of the base station represents the connection between the external power supply SV and the device for energy storage battery.

When the power supply SV is switched on, both the energy storage device designed as a battery and the base station BS are supplied with an alternating voltage of 230 volts. At the same time, the power supply SV serves to operate the lighting device L, which is located in the lower part of the housing G.

According to FIG. 2d, the communication connection KA can alternatively also be made by a radio connection, antenna units being mounted on the housing G, which are connected to adjacent lighting devices or similar devices via a radio interface which is pronounced in the sense of a directional radio link. The radio interface can be operated via infrared signals, in a frequency band reserved for directional radio or in the frequency band for road traffic communication devices (eg for toll systems or for a car radar) or even in the frequency band of the communication system.

According to a further version of the base station BS, a radio channel, which can also be used to supply the cell, is used for the communication connection KA. With a number of lighting devices with base stations BS, only a subset of wired communication technology would have to be supplied, while the others in the manner mentioned above in the sense of a daisy chain, or the like. be supplied.

Since the distances to be covered by the radio connections are small, it is possible to work with low transmission powers and space-saving antenna devices. Atmospheric disturbances are insignificant at these short distances and disturbances to other communication systems are minor.

2b and 2e show the housing G of the lighting device in a view from the bottom perspective. The light emitter L, the radiation diagram of which is conical, has an optically little shaded radiation aperture to the earth's surface. Antenna devices AE are mounted on its side, which, as antenna devices of the base station BS, provide the radio technology for the microcell. The antenna devices AE can also be combined with antennas for the communication connection KA.

A gap is shown in FIG. 2e, which can accommodate an ascending air flow below and alternatively also at the edges of the housing. This air flow penetrates into the housing G and is thermally connected to a device KA for cooling the base station BS. The chimney effect and the flow of the rising air create an additional cooling effect for the base station BS. It can be provided that the light emitter L is thermally insulated from the base station BS. Alternatively, the base station BS can be preheated by the light emitter L by controllable heat transfer, for example during the night. The design of the thermal coupling between the light emitter L and the base station BS can be used particularly advantageously if the base station BS is switched to a stand-by mode during the night, for example.

To cool the base station BS, the strongly heated devices can be mounted on a heat sink which is thermally conductively connected to the outer wall of the housing G. Likewise, fresh air can penetrate laterally into the housing G in the sense of a wind turbine and contribute to cooling the base station BS.

2c and 2f show a view from above of the housing G of the lighting device. Air outlet slots are provided on the top of the housing G or on the sides, which are provided for cooling K of the base station Bs and enable the air outlet. These slots are protected against the ingress of rainwater. In addition, according to FIG. 2f, a device S for solar power supply is provided, which is connected to the battery (rechargeable battery) or directly to the power supply SV. Part of the light radiation is absorbed via a solar panel and converted into electrical energy, which contributes to the power supply of the base station BS.

3 shows a lighting device designed as ceiling lighting, in which a base station BS is integrated. In addition to the external power supply SV, which is provided for the lighting device and the base station BS, there is a communications connection KA which connects the base stations BS to other devices of the mobile communication system, for example a base station controller.

The lighting device is installed in the ceiling of the interior such that an opening for the light emitter L and surfaces for the installation of antenna devices AE of the base station BS are visible.

The integration of the base station BS into the housing G of the lighting device can lead to the complete inclusion of the base station in this housing G or only to partial inclusion.

According to FIG. 4, for cooling the base station BS, the opening for the light emitter L and possibly additionally the antenna devices AE are introduced into an access for an air conditioning system K, the air conditioning system K being used simultaneously for cooling the base station BS.

5 shows an optical signaling device in the form of a traffic light. Traffic lights of this type are used for signaling for road-bound vehicle traffic, but also for other means of transport and for pedestrians. These traffic lights are thus installed at road crossings at a mounting height of more than 2.5 meters on masts or also hanging on ropes. For details of the assembly and design of traffic lights, reference is made to US Pat. No. 2,925,458.

5 has a housing G and a plurality of light emitters L, the signaling device being connected to an external power supply SV and a device for lightning protection B. The power supply is, for example, a 230 volt AC voltage. Lightning protection B of the signaling device is implemented via the mast by earthing at the foot of the mast.

A base station BS is integrated in the housing G of the signaling device. This base station BS is constructed as described in FIGS. 1 and 2.

Antenna devices AE of the base station BS are mounted on the outer wall of the housing of the signaling device, whereby an omnidirectional characteristic or directional radiation can be achieved. The antenna devices AE of the base station BS provide the radio technology for the microcell. The antenna devices AE can also be combined with antennas for the communication connection KA. According to an alternative embodiment, the communication connection KA is made by controlling the signaling device. In particular in networked traffic management systems, for example in large cities, transmission routes that have already been laid are thus also used.

As with the lighting device, it is advantageous to couple the design of the antenna devices AE to that of a light emitter L. A recess in the housing G of the signaling device can accommodate the light emitter L for optical signaling and an antenna device AE. The light emitter L and the corresponding antenna device AE thus have similar radiation diagrams.

It is known to connect the control of a signaling device to the volume of traffic, for example by extending the traffic light phases for the particularly stressed forward direction in a traffic light. In the same way, the information about the traffic volume can be used to control the base station BS. If there is a high volume of traffic - there is usually also a high demand for communication technology supply - additional frequency channels can be switched on, for example.

According to FIG. 6, the optical signaling device is designed as a traffic sign with light emitter L. Many traffic signs or information signs are illuminated to make them more visible. The inner illumination shown in FIG. 6 is realized by a light emitter L, which is arranged in the housing G of the traffic sign and the radiation of which shines through, for example, a glazed outer wall of the housing G. The signaling message of the traffic sign is affixed to this glazed outer wall. This signaling message is clearly visible in the dark through the lighting. A base station BS is additionally integrated in the housing G. Antenna devices AE are attached to one or more outer walls of the housing G and thus ensure the intended radio technical supply.

When selecting and installing the lighting or signaling devices described above, it should be noted that locations with a high number of people are selected. It is also important to ensure that the road users stay in the radio area of ​​the base station for as long as possible, so that zones with stationary traffic are preferable to zones with flowing traffic.