CN1267413A

CN1267413A - Method of improving air interface performance in radio telephone system

Info

Publication number: CN1267413A
Application number: CN 98808363
Authority: CN
Inventors: 奥利·皮雷宁
Original assignee: Nokia Networks Oy
Current assignee: Nokia Oyj
Priority date: 1997-08-21
Filing date: 1998-08-19
Publication date: 2000-09-20
Also published as: WO1999013651A2; FI973439A; EP1021877A2; FI973439A0; AU8809898A; NO20000804L; JP2001516996A; WO1999013651A3; NO20000804D0

Abstract

The invention relates to a method of improving performance of an air interface (170) that exists between a base station (100) and a subscriber terminal (150) in a radio telephone system. In accordance with the invention, parameter values of an environment database (180) controlling the operation of the air interface (170) are adjusted to correspond to the operating conditions of the base station (100). The parameters comprise, for example: a selection between the base station (100) receiver sensitivity limitation and co-channel interference limitation, a maximum accepted speed of the subscriber terminal (150) communicating with the base station (100) via the radio connection (170), the diameter of the cell of the base station (100), a maximum delay spread, information indicating whether neighbouring base stations are synchronous.

Description

Improving one's methods of air interface performance in the radio telephone system

The present invention relates in the radio telephone system improving one's methods of aerial interface capability, the air interface that wherein wireless connections realized is between base station and user terminal.

In the prior art, by being installed, auxiliary equipment improves the control interface performance in the base station.By antenna for base station being placed in special mast structure top, obtain the area of coverage of audibility and broad preferably, thereby the operational environment that will for example be positioned at the base station, rural is taken into account.In addition, can use the antenna amplifier antennafire that for example is placed in the mast top.

A problem of such scheme is that it needs extra-pay.In addition, such scheme requires careful planning, makes necessary parts can transport to the infield, thereby finishes installation at predetermined instant.

Therefore, an object of the present invention is to provide the equipment of a kind of method and this method of realization, in order to address the above problem.This realizes by the method that provides in the preorder, it is characterized in that, adjusts the parameter value of the environment data base of control operated, makes its operational environment corresponding to the base station.

The invention still further relates to a kind of base station in the radio telephone system, the air interface of this system is realized by the wireless connections to user terminal.According to the present invention, this base station is characterised in that in this base station, the operation of air interface is controlled by environment data base, and the parameter value of environment data base can be set, and makes its operational environment corresponding to the base station.

The preferred embodiments of the present invention are open in relevant claim.

Basic thought of the present invention is, the overall performance of the air interface in the operational environment of base station improves the operation of base station in the following manner: as long as can be improved, even the deterioration with other parameter values is a cost, also optimize some parameters that influence operated.

Method and system of the present invention provides a plurality of advantages.The present invention does not also require auxiliary equipment is installed in the base station.Adjust the operation of base station according to the condition of installation site, it is optimized.The present invention might not be directly used in installation, and it also can be realized after coming into operation in the base station.When environment for use database not, necessary type approval requirement is satisfied in base station of the present invention.Under given conditions, if used environment data base, some characteristics even can not meet standard also can be guaranteed best possible performance.If this can't accept, then still can in the desired standard limit of type approval, optimize the operation of base station.

Below in conjunction with accompanying drawing, describe the present invention in detail by preferred embodiment, in the accompanying drawings

Fig. 1 shows an example of the structure of radio telephone system of the present invention;

Fig. 2 shows the structure of transceiver.

Fig. 1 shows the general structure of radio telephone system of the present invention.Only comprised important components of the present invention among Fig. 1, but those skilled in the art understand obviously that conventional radio telephone system also comprises does not need other operations and the structure described in detail herein.These examples show the wireless digital telephone system that adopts TDMA, but the present invention is applicable to various types of radio telephone systems, is applicable to FDMA, CDMA and dissimilar integrated systems, also is applicable to analog radio systems.

Radio telephone system generally comprises landline telephone infrastructure, i.e. network portion, and user terminal 150, this terminal can fixed in position, also can be installed on the vehicle or in the hand-held terminal device.Network portion comprises base station 100.A plurality of base stations 100 are by base station controller 102 centralized control that communicate with.Base station 100 comprises transceiver 114.Base station 100 generally comprises 1 to 16 transceiver 114.In tdma system, for example a transceiver 114 is a tdma frame, in other words, is generally 8 time slots, and wireless capacity is provided.

Base station 100 comprises the control unit 118 of control transceiver 114 and multiplexer 116 operations.Multiplexer 116 is assigned to a transmission with a plurality of transceiver 114 used Traffic Channels with control channel and is connected 160.

Base station 100 transceivers 114 are communicated by letter with antenna element 112, and the latter has realized that the double-direction radio of user terminal 150 connects 170.Connect 170 at double-direction radio, be called the frame structure that transmits on the air interface by explication.

Fig. 2 has provided the detailed description of the structure of transceiver 114.Receiver 200 comprises a filter, and it blocks the frequency outside the required frequency range.Then, conversion of signals is become intermediate frequency or directly is transformed into base band, afterwards, 202 pairs of signal samplings of analog to digital converter and quantification.Equalizer 204 compensates the interference that for example multipath transmisstion caused.Demodulator 206 bit stream of extracting from equalizing signal sends to demultiplexer 208 with this bit stream.Demultiplexer 208 becomes different logic channels with this bit stream demultiplexing from different time slots.The bit stream of channel coding-decoder 216 decoding Different Logic channels, in other words, it infers that this bit stream is to comprise the signaling information that need send control unit 214 to, still need send to the voice of the audio coder ﹠ decoder (codec) 122 of base station controller 102.Channel coding-decoder 216 is also finished error correction.Control unit 214 is realized the internal control task by the control different units.Pulse train maker 228 increases training sequence and tail on from the data of channel coding-decoder 216.Multiplexer 226 is assigned to particular time-slot every pulse train.Modulator 224 is modulated to radio-frequency carrier with digital signal.This is the operation that requirement digital to analog converter 222 is carried out.Transmitter 220 comprises the filter of a limiting bandwidth.In addition, transmitter 220 controls send power output.Synthesizer 212 generates required frequency for different units.Synthesizer 212 comprises a clock, and the latter can local control, perhaps from elsewhere, and for example by base station controller 102 centralized control.Synthesizer 212 generates for example required frequency of voltage controlled oscillator.

Base station controller 102 comprises group switching domain 120, code converter 122 and control unit 124.Group switching domain 120 is used for the voice-and-data exchange, and connects signaling circuit.The code converter 122 conversion public switched telephone networks different digital speech code form used with radiotelephony network, make them be applicable to the opposing party, for example 64 kbit/s format conversions from fixed network become certain extended formatting (for example 13 kbit/s), and vice versa.Control unit 124 is finished collection and the Signalling exchange of calling out control, mobile management, statistical information.

In the example of Fig. 1, by mobile switch 132 connections of foundation from user terminal 150 to the telephone set 136 that is connected to PSTN 134 (public telephone switching network).

The operation of the radio telephone system that OMC (operation maintenance center) control and monitoring are communicated by letter with mobile switch 132.OMC 138 generally is the stronger computer of function that comprises special software.Control also can concentrate on the different piece of system, provides the required control channel that sends control information because can connect to the transfer of data between the different piece of system.

In addition, the personnel that network and its use of monitoring be installed can utilize and management software 140 (EM=NE management) portable computer for example has been installed is managed single network element.In the example of this figure, equipment 140 is connected to the tcp data segment of the control unit 118 of base station 100, and it can monitor and control the operation of base station 100.It can check that also Change Example is as the value of the parameter of control base station operation.

According to the present invention, base station 100 comprises environment data base 180, is used to control the operation of air interface 170.Environment data base 180 comprises different parameters, and the value of these parameters can be provided with according to the condition of work of base station 100.These parameters can be adjusted in the erection stage and the operational phase of base station.Its value is not adjusted, promptly adopt the environment data base 180 of default value, air interface 170 operate as normal.100 the erection stage in the base station, environment data base 180 may not exist, and perhaps do not come into operation, thereby base station 100 is operated in normal mode.Afterwards, can integral body or increment type increase environment data base 180, thereby the parameter of environment data base 180 begins to control the operation of the air interface 170 of base station 100.

The parameter of environment data base 180 can be provided with by for example above-mentioned OMC 138 and/or NE management computer 140.

The present invention preferably realizes by software, thereby the present invention only need be to the control unit 118 of base station 100, and may make relative simple software to the part of definite appointment in the control unit 214 of each transceiver and revise.In addition, the present invention needs environment data base 180 naturally, and its size and complexity alter a great deal, and simple parameters is to be easy to the word that uses and understand.Environment data base 180 can be realized by general preservation, search and the update service that database software provides technically, may have this database software in the base station 100 and be used for other purposes.

Following let us is investigated the use of the inventive method under the different situations by simple example.

Let as assume that base station 100 is positioned at the rural area.In this case, the operation of its receiver is limited by its sensitiveness.Antenna 112 preferably is placed on the mast to increase audibility.There are not other transmitting sets caused probably, the interference signal that in the GSM standard, illustrates.In this case, sensitiveness that can following improvement receiver: increase the multiplication factor that is installed in the simulation low noise type antenna amplifier on the antenna 112, thereby reduce the obstruction of interference signal.Like this, can reach the compromise of the satisfaction that is fit to base station 100 environment, improve the overall performance of base station 100.

If base station 100 is positioned at the city, then operation is subject to the cochannel interference probably, compares with rural situation, and the sensitiveness of receiver is not very important.In this case, in digital signal processing, when the cochannel interference occurring, can adopt the different types of interference removing method to improve base station 100 receiver performances.On the other hand, interference elimination method has reduced the sensitiveness of base station 100 receivers usually.In other words, as long as improved overall performance, worsening with receiver sensitiveness so is that cost is supported the cochannel interference eliminated.

Under the situation of city, the speed accepted of travelling carriage 150 is often limited.Base station 100 utilizes this information Control to entangle frequently according to speed, for example controls adaptive equalizer 204.

The maximum delay expansion can be limited in the base station 100 that is operated in less sub-district or internal zone.This means can restricting channel impulse response lasting duration, improve receiver performance (with regard to sensitiveness and interference-tolerant) equally.

If base station 100 has synchronous adjacent base station, then can utilize such interference elimination method, the training sequence in this method requirement signal that interference base station sent and the training sequence of desired signal are overlapping.

If the operation of the transmitter of base station 100 is controlled by environment data base 180, then also the operation that improves air interface 170 on the downlink transmission path of user terminal 150 can led to.Its example is the control smart antenna solutions, because phase place is randomized, and the optimised operational environment separate antenna signal of being arranged to according to base station 100 of delaying time, they can be by the measurement control of carrying out in the described environment.

Although example has below in conjunction with the accompanying drawings been described the present invention, obviously the present invention is not limited thereto, but can improve in several ways in the disclosed innovative idea scope of appended claim book.

Claims

1. a kind of the improving one's methods of aerial interface (170) performance in the radio telephone system, the air interface that wherein wireless connections realized (170) is positioned between base station (100) and the user terminal (150), it is characterized in that, adjust the parameter value of the environment data base (180) of control air interface (170) operation, make its condition of work corresponding to base station (100).

2. according to the method for claim 1, it is characterized in that, at the parameter that its value does not adjust, air interface (170) operate as normal.

3. according to the method for claim 1, it is characterized in that these parameters are represented by wieldy guide word.

4. according to the method for claim 1, it is characterized in that these parameters are included in the selection of being done between base station (100) receiver sensitiveness restriction and the cochannel interference-limited.

5. according to the method for claim 1, it is characterized in that these parameters comprise the maximal rate accepted that the user terminal (150) of wireless connections (170) is arranged with base station (100).

6. according to the method for claim 1, it is characterized in that these parameters comprise the diameter of sub-district, base station (100).

7. according to the method for claim 1, it is characterized in that these parameters comprise the maximum delay expansion.

8. according to the method for claim 1, it is characterized in that whether synchronous these parameters comprise indication adjacent base station information.

9. according to the method for claim 1, it is characterized in that the erection stage of (100) is adjusted at least some parameters in the base station.

10. according to the method for claim 1, it is characterized in that adjust at least some parameters the operation stage of (100) in the base station.

11. a kind of base station (100) in the radio telephone system, the air interface of this system (170) is realized by the wireless connections to user terminal (150), it is characterized in that, in this base station (100), the operation of air interface (170) is controlled by environment data base (180), the parameter value of environment data base can be set, make its condition of work corresponding to base station (100).

12. the base station according to claim 11 is characterized in that, at the parameter that its value does not adjust, and air interface (170) operate as normal of base station (100).

13. the base station according to claim 11 is characterized in that, these parameters are represented by wieldy guide word.

14. the base station according to claim 11 is characterized in that, these parameters are included in the selection of being done between base station (100) receiver sensitiveness restriction and the cochannel interference-limited.

15. the base station according to claim 11 is characterized in that, these parameters comprise the maximal rate accepted that the user terminal (150) of wireless connections (170) is arranged with base station (100).

16. the base station according to claim 11 is characterized in that, these parameters comprise the diameter of sub-district, base station (100).

17. the base station according to claim 11 is characterized in that, these parameters comprise the maximum delay expansion.

18. the base station according to claim 11 is characterized in that, whether synchronous these parameters comprise indication adjacent base station information.

19. the base station according to claim 11 is characterized in that, the erection stage of (100) is adjusted at least some parameters in the base station.

20. the base station according to claim 11 is characterized in that, adjust at least some parameters the operation stage of (100) in the base station.