WO2000025544A1

WO2000025544A1 - Method of establishing at least one quality estimate of a communication network

Info

Publication number: WO2000025544A1
Application number: PCT/DK1999/000578
Authority: WO
Inventors: Jan Elling; Thomas Toftegaard Nielsen
Original assignee: Dansk Mobiltelefon I/S
Priority date: 1998-10-22
Filing date: 1999-10-21
Publication date: 2000-05-04
Also published as: AU6326299A

Abstract

The invention relates to a method of establishing at least one quality estimate in a communication network for one or more sets (S1, S2, S3, S4, ...., Sn) of possible signal representations for each radio frequency in a given combination of a number of various radio frequencies (CH1, CH2, ...., CHn), wherein each set has been provided with a given estimate of quality (EOQ) for the signal quality of a signal received by a receiver (BSS, MS), said estimate of quality being a quality measure for a decoded signal received at a receiving unit (BBS, MS) in a network. According to the invention, it is possible to obtain a method of establishing at least one quality estimate which may be used for effective cost optimalization of a mobile communication network. Cost optimalization is defined as the subscriber's experience of the quality of the net, the investment in equipment for establishment and structure of the net together with reresource allocation efficiency, operation and maintenance of the net.

Description

Method of establishing at least one quality estimate of a communication network

Background of the invention

The invention relates to a method as specified in claim 1, means for allocation of radio frequencies in a mobile communication network as specified in claim 5, a method of establishing a reference base comprising one or more QOS estimates as specified in claim 13 and a method for allocation of carrier frequencies in a radio network as specified in claim 17.

The allocation of a network to be used in connection with mobile communication, e.g. cellular telephony, is a quite complicated and expensive affair. Investments in employees and equipment are substantial.

A mobile communication network is generally based on exchanges connected mutually and with radio transmitter/receiver stations and base stations with which the mobile exchanges have a wireless radio connection.

A typical mobile communication network generally consists of a mobile switching center (MSC) as the primary control unit. This is directly connected to other MSCs and a number of BSSs. A BSS consists of a base station central in control of and with connections to a number of base stations (BTS) that, in turn, are capable of creating a wireless connection to or from a mobile subscriber (MS). The mobile switching center are also connected to other networks at a similar level. Examples of these are e.g. fixed switching centers such as PSTN, ISDN, mobile communication networks and computer networks PSDN.

With this structure, a mobile subscriber placing call would be connected to the base station with the best connection to the mobile subscriber wirelessly. From the base station, the call is transferred via the mobile switching center to the network where the phone or the telecommunication equipment with which contact is desired is located. In order to ensure that a mobile subscriber is always capable of making contact with a base station, the base stations must be located in a close-meshed net in any given area so that a satisfactory coverage of the entire area is established. Coverage is defined as any given place provided with a sufficiently strong signal to maintain the balance between broadcasting and transmitting between the base station and the mobile subscriber (MS).

Similarly, the radio frequency channels available must be utilized in the best possible manner, e.g. by the use of frequency hopping.

Thus, depending on the current wireless transmission conditions between a base station BTS and a mobile subscriber MS, an MS would be capable of communicating with a base station to which the given MS has been allocated by means of automated algorithms while taking into account the quality of the signal of the MS and/or BTS.

Each of the above-mentioned base stations have been allocated a number of channels. In principle, each channel is made up by a carrier frequency working as a signal leader between the MS and the base station through appropriate modulation and coding.

The number of channels in use at the individual base stations are, among other things, determined by the number of active subscribers at the individual base stations. If the individual base stations are located in an area with many active mobile subscribers, a large number of channels is required whereas base stations located in less busy areas require less channels.

Meanwhile, a problem related to the allocation of a mobile communication network is that the number of available channels is significantly limited. Apart from that, the number of available channels in a given area, e.g. Denmark, is divided between a number of operators where each operator must handle the allocated channels very carefully. This problem becomes even more apparent when looking at national borders where the availability of channels is further reduced and often by more than 50%.

Another related problem is that the allocated channels may not be uncritically used. If a given channel is used at a base station, the carrier frequency will interfere with one or more adjacent stations if it is using the same channel at these base stations.

Together with other quite complicated issues, this fact must be broadly considered when allocating a network just as it should be ensured that the channel allocation to the individual base stations is as optimal as possible. If one base station is allocated too few channels, the capacity of the base station is limited and if allocated too many or wrong channels, the quality of the radio interface for surrounding interfering adjacent base stations is reduced. The more channels, the greater the risk of quality deterioration.

Thus, it is important to avoid limited capacity, just as it is important to avoid excess capacity at a given base station which will either block or impair the transmission of the adjacent base stations.

New network allocation means seek to solve the problem with the above-mentioned optimalization by applying additional parameters such as site, defined channel demand, traffic, geography, topography, factors describing the conditions of the area and the transmission of radio waves. Conditions of the area may e.g. include dense population, small towns, the country side, woods, seas, lakes etc. The prediction of the transmission of radio waves also takes the mentioned factors into account.

A starting point for the existing network frequency allocation is the establishment of a classical signal quality measures in a given geographical area to which one or more of the above-mentioned parameters are subsequently weighed with. The classical measure may e.g. be a calculated value estimating the signal quality at a given geographical coordinate as an effective signal for each channel in relation to a calculated interference signal. This signal, e.g. represented in dB, may be C/I (the carrier signal to the interference signal ratio). For the mobile communication network system GSM, the limit for C/I, according to the ETSI GSM recommendations is a minimum of 9 dB for co-channel interference and a minimum of -9 dB for interference of adjacent channels (C/A).

Today, basically two network allocation techniques are being applied. The oldest technique has based the allocation on the establishment of reuse patterns. Each reuse pattern is constructed by a number of clusters that use all available frequencies in unison. Once such a cluster is established, the network may subsequently be constructed by repeating the cluster over the entire network. The most commonly used reuse patterns in the GSM network are 4/12 or 3/9. If each base station is allocated three cells, 3/9 reuse patterns mean that the available frequencies are divided into nine groups that have, in turn, been divided and allocated to three adjacent base station sites.

A disadvantage of the reuse pattern technique is that the model presupposes a uniform traffic allocation level between the cells and that these cells have a homogenous service area with similar environments. However, in reality, the traffic and the best servers of each cell are non-homogenous just as the environments are non-homogenous.

This results in the network allocation means not being useable for optimalization of the use of the radio frequency resource and the communication quality in real life.

Another existing techmque is based on the establishment of constraints and relations between network elements (often between cells) representing local conditions in the network such as traffic, geography and topology. These algorithms representing an NP - hard problem are subsequently optimized by a combined automated and manually analysis. Meanwhile, a problem with the latter technique is that it cannot handle so-called FH networks (frequency hopping networks) which is the reason why the gain achieved with FH cannot be included in the optimalization and the allocation.

The invention

By, as specified in claim 5, letting a means for allocation of radio frequencies in a network comprising

a reference base (RB) consisting of one or more sets (SI, S2,...., Sn) of possible radio frequency in a given combination of a number of various radio frequencies (CH1, CH2, ...., CHn),

wherein each set has been provided with a given estimate of quality (EOQ) for the signal quality of a signal received by a receiving (BSS, MS), said estimate of quality being the quality measure for a decoded signal received at a receiving unit (BSS, MS) in a network ,

it is possible to obtain an efficient network allocation means that produces estimates of quality reflecting the actual quality as opposed to previously known network allocation means that only took into account general classical quality measures.

Thus, according to the invention, a reference base has been established which is capable of creating a more realistic estimate of quality by using inputs of all possible signal levels (signal representations) available reflecting what a subscriber on a mobile communication network would actually experience in a real-life corresponding system. This physical condition is preferably established on the basis of the channels and corresponding fictitious levels to be used in the available set of channels and on the basis of interference signals of adjacent base stations. Such a representation may e.g. be represented by the value C/I (carrier signal to interference signal ratio). By using a C/I representation for each of the available channels, it will be possible to relate a given set of available signal levels, also C/I values, to corresponding real-life, measured or analytically calculated or predicted C/I values at given coordinates thereby obtaining a estimate of quality stating whether a given base station - when combined with other base stations - is capable of providing satisfactory coverage/service in a given area.

By establishing an estimate of quality relating to the given C/I values at a given coordinate, it becomes possible to optimize the allocation of a network since it is no longer the classical worst-case analytical/predicted representations that are the starting point for the network allocation means.

One particular advantage must be seen in relation to the fact that a network allocation means, in accordance with the invention, is capable of combining the advantages obtained by a frequency hopping network with the advantages obtained by weighing the allocation with local/geographical characteristics. According to the invention, it has thus become possible to make various plans for mobile communication networks irrespective of whether some or several of the base stations make use of frequency hopping.

It should also be noted that the estimate of quality may be established as an estimate from the transmitter of the base station to a mobile receiver (downlink estimate) or as an estimate from a mobile transmitter to a receiver at the base station (uplink estimate).

Therefore, it is implicit that the estimate of quality, according to the invention, may be established by real-life tests or simulation. In practice, the estimate of quality may be established by means of a link-simulator. The use of the estimate of quality in relation to the allocation and the optimalization of the network may be validated by means of a network simulator.

One reason for the importance of the decoding in relation to the invention is that it provides/creates a signal improvement that cannot be illustrated in C/I values as has previously required by existing allocation means. According to the invention, the signal representation levels may e.g. be C/I values expressed in dB. Various other representations, e.g. weighed or converted C/I values, could also be used.

By, as specified in claim 6, letting the possible signal representations for each radio frequency in a given combination of radio frequencies (CHI, CH2, , CHn) being specified to a given location where each set has been provided with a given estimate of quality (EOQ) for the signal quality of a signal received by a receiver (BSS, MS) at the said location, a means is obtained that may be used in an effective allocation of a mobile communication network.

By, as specified in claim 7, letting the number representations being made up by C/I values or strongly correlating measures for BER, it is possible to obtain an advantageous embodiment, according to the invention, since existing allocation means typically generate weighed C/I values that may subsequently be converted into EOQ estimates, according to the invention.

It is implicit that the given C/I values should advantageously be weighed with a geographical location.

By, as specified in claim 8, letting the estimate of quality be stated as a Frame Erasure Rate, it is possible to obtain a particularly advantageous embodiment, according to the invention, since FER is an established rate that may already be extracted from the existing GSM protocol with reference to the ETSI GSM recommendations. According to the invention, it is possible to obtain a reference base wherein the individual estimates may be established by fairly simple tests on real-life or simulated links between a transmitter and a receiver.

According to the invention, it should be noted that a reference base requires a fairly large number of estimates in order to be useable in practice which is also the reason why the establishment of the individual estimates should be as simple as possible. This ratio increases exponentially with the number of available channels while the number of available combinations also increases exponentially. Mathematically, this ratio may be described as an NP hard problem.

By, as specified in claim 9, establishing an estimate of quality by means of a link- simulator simulating the radio interface between a base station (BSS) and a mobile subscriber (MS), it is possible to obtain another advantageous embodiment, according to the invention, as a link-simulator is capable of emulating the radio interface between the transmitter and the receiver whereby superfluous and time- consuming real-life tests may be avoided. Another option is to validate the estimate of quality by means of a network simulator.

By, as specified in claim 10, establishing an estimate of quality by means of a listening test, it is possible to obtain an advantageous embodiment according to the invention since the estimate of quality is established on the basis of the radio interface and a decoding of a signal from the receiver may be attached to specifications corresponding to the psycho acoustic expectations which a subscriber may have to the received signal.

By, as specified in claim 11, letting the network be a frequency hopping FH network, it is possible to obtain a particularly advantageous embodiment, according to the invention, as the potential improvements of the radio interface created by frequency hopping can now be included in the network model. Thus, an allocation means must no longer be based purely on worst case analyses but can also be based on conditions closer to the actual prevailing radio interface. As the use of frequency hopping creates an improved radio interface, these improved transmission abilities will all be reflected by the allocation means. This provides significant additional advantages in relation to the further allocation of a network as the number of adhesions in the network model may in principle be reduced and the allocation simplified. This must be seen in connection with the fact that existing means have had to base the allocation on quality parameters which have not reflected reality but have instead been based on exaggerated pessimistic estimates of the actual conditions. That, in turn, has resulted in the system planners being forced to make unnecessary compromises which have reduced the quality of certain parts of the network, just as its has been necessary to devote extra reresources to the system allocation represented by qualified and experienced employees and consequently a long allocation period.

According to the invention, the allocation means would represent an allocator for the real-life adhesions on the system which reduces the requirements to the degree of education and experience that a user of the network means should possess as a minimum.

In connection with the FH network, the means would be capable of creating a network, according to the invention, whose base stations are placed optimally just as the distribution of allocated channels in each base station will be optimal. This cost optimalization would naturally also result in an improved radio interface quality.

By, as specified in claim 12, weighing the estimate of quality EOQ against a given cellular phone with acoustic properties, it is possible to obtain another advantageous embodiment, according to the invention, as the quality of the cellular phones from the individual manufactures may be evaluated by simple testing.

Figures

The invention will be described in detail in the following with reference to the drawings where Figure 1 shows an example of a mobile communication network

Figure 2 shows an example of a frequency allocation chart according to the existing technique Figure 3 shows a flow chart of a GSM receiver Figure 4 shows an example of a mobile communication network Figure 6 shows a schematic outline of the allocation means of a network, according to the invention and Figure 7 shows an example of a frequency allocation chart, according to the invention.

Detailed description Figure 1 shows a typical mobile communication network that generally consists of exchanges connected to each other, to radio transmitter/receiver stations and base stations to which the mobile subscribers have a wireless radio connection.

A typical mobile communication network essentially consists of a mobile switching center MSC as the primary control unit. This MSC is directly connected with other MSCs and a number of BSSs. A BSS consists of a base station central in control of and connections to a number of base stations BTS capable of creating a wireless connection to or from a mobile subscriber MS. The mobile switching centers are also connected to other networks such as e.g. PSTN, ISDN, a mobile communication network, the internet or a data network PSDN.

With this structure, a mobile subscriber placing a call would be connected to the base station with the best connection wirelessly. From the base station, the call is transferred via the mobile switching center to the network where the phone or the telecommunication equipment with which contact is desired is located.

In order to ensure that a mobile subscriber is always capable of making contact with a base station, the base stations must be located in a close-meshed net in any given area so that satisfactory coverage of the area is established. Also, the available frequency channels must be utilized in the best possible way by e.g. frequency hopping.

Computer equipment is made available to all operators to assist with the allocation of a mobile communication network. The computer equipment available on the market today provides the opportunity to determine values indicating whether the degree of coverage at a given position is satisfactory. By determining the values of all positions in an area and dividing them into appropriate intervals, it is possible to construct a chart of the coverage in the area where the intervals are represented by colours. In this manner, it is possible to create a coverage chart on the basis of simple mathematical calculations to be allocated on a frequency-planning chart.

The values in the frequency allocation chart are basically made up by the ratio between the transmission power from a base station and the interference from one or more other base stations (C/I).

In order to eliminate problems experienced by the subscribers of a mobile communication network, the operator will estimate the C/I under the worst possible conditions which is done by determining the ratio between transmission power from the base station with the most transmission power at a given location, also called the "best server", and the most powerful accompanying signal from the interfering base stations.

When making the estimate of the signal power from the base stations, knowledge of the given physical conditions in area are taken into account by using an adjusting factor reflecting the conditions of area. This factor may e.g. be helpful in taking into consideration undulating land, woods or densely populated areas with many high buildings.

Figure 2 shows an example of how a frequency allocation chart for C/I looks where the colours white and black symbolize the best and the worst interference conditions respectively and black represents the worst C/I of 0 dB.

As is apparent from the figure, there is quite a few black items where the operator must expect the subscriber of the mobile communication network to experience great problems with achieving a satisfactory quality in the transmission of his/her phone conversations if it is possible to establish a connection to the network at all. However, the operator has various options available to him for solving this unsatisfactory situation. If he is already using all available radio frequencies allocated to him in connection with the operating licence, he may put up additional base stations, move them around or change the locations where the radio frequency signals may be used and which base stations should transmit and receive which channels. In other words, the frequency plan must be restructured.

Also, he may opt to use frequency hopping and thereby utilize the network capacity better. Irrespective of his choice, his actions will affect the operation of the total network whereby improvements in one place easily trigger problems in other places.

Figure 3 is a flow chart of a GSM receiver.

A received signal for a given RF channel, RFC, is demodulated and digitalized in a demodulation step DM in accordance with the chosen encoding which is GMSK for GSM.

In the blocks DC and BP, the signal is deciphered and burst formatted.

At the DI block, the burst formatted signal of the BP block is de-interleaved. In practice, this means that the signal is spread out in message blocks. One error in a single frame will thus be spread out on the number of originally multiplexed channels.

In practice, this means that the signal is spread out in message blocks. One error in the entire frame will thus be spread onto the number of the originally multiplexed channels.

On such an occasion, an error estimate called a Bit Error Rate (BER) is established in the GSM protocol expressing the number of bits that have been lost in the transmission. Since potentially lost data in the radio interface is now spread onto each of the established channels, a lost frame in the radio interface will e.g. result in only one error bit in each message block of each channel.

In GSM, the original frames of 456 bit are regenerated by de-interleaving. Subsequently, decoding is conducted of each of the channels regenerated by de- interleaving whereby a part of the errors arisen in connection with the transmission are adjusted by error recovery.

An additional measure for the data quality, also the Frame Erasure Rate, FER, is established for each 456 bit frame established in the GSM.

Finally, a resource decoding is made at the SD block whereby the data flow is converted and regenerated into analogue speech frames of 20 ms each.

This analogue signal may subsequently be reproduced in a subscriber's transducer.

In this connection, it should be noted that decoding of the individual channels is made between the BER and the FER which may result in a significant data recovery under certain circumstances which is the reason why a measure for the signal quality should be established subsequent to the decoding of the de-interleaved channels. The gain of frequency hopping especially comes from the decoding.

Frequency hopping is a technique that implies the changing of the radio frequency at certain intervals. The frequency hopping technique originates from the communication systems of the military where its purpose was to protect communication lines against tapping and jamming, especially during war times. Frequency hopping may be characterized by two techniques: Fast frequency hopping, FFH, where the radio frequency is changed faster than the modulation rate and slow frequency hopping, SFH, where the frequency is changed slower than the modulation rate. The GSM system makes use of the SFH technique.

Generally, frequency hopping improves the speech quality in a communication system. In short, instead of placing and receiving calls that may vary quite a lot in quality, frequency hopping improves all calls so that they are all of a good - or at least acceptable - quality. The gain from frequency hopping is typically described by two fundamentally different facts: the frequency diversity gain and the interference diversity gain. At the same time, the gain may be rephrased as a capacity increase possibility since frequency hopping offers the opportunity to better reutilize a radio resource (radio frequency) than is the case without frequency hopping.

Frequency diversity is a gain which is dependent on the subscriber's subscription or mobility as the gain is dependent on movement speed.

The interference diversity is dependent on the network topology and the network load, making it dependent on the strategy of the operation in relation to the realization of the communication network such as e.g. be a mobile communication network. Without frequency hopping, the relative interference ratio (C/I or C/A) would vary from call to call and be more dependent on the way the radio frequencies have been organized (large degree of dependency on the frequency plan), traffic allocation, radio conditions in the area, environmental conditions etc. With the use of frequency hopping, the interference situation is changed for each radio transmission (GSM: for each burst) which will reduce the interference conditions.

Figure 4 shows an example of a radio communication network consisting of three transmitter/receiver posts X and of cells Y symbolizing their transmission range. As can be seen from the figure, an overlap takes place resulting in interference between identical or closely situated channels that are used by more posts in close proximity to each other. However, such interference depends on the load on each post and the load on the cell in question and the interfering cells should therefore also be taken into account when calculating the C/I at a given location Z. The value arising from such a calculation is called C/IL_OAD-

The function of C/I_LOAD is, in a preferred embodiment, to calculate an EOQ estimate, such as FER, whereby it is possible to obtain a significantly improved impression of the given conditions in a cell. Figure 6 is an illustration of a preferred embodiment, according to the invention.

According to this embodiment, a number of sets SI, S2, S3, S4, ...., Sn would be organized in an input matrix. The sets of the input matrix SI, S2, S3, S4, ...., Sn would comprise a C/I value for each channel, or carrier frequency, CHI, CH2 and CH3.

Each combination of C/I values SI, S2, S3, S4, ...., Sn are converted via a reference base RB into a corresponding estimate of quality EOQ.

It is implicit that the input to the reference base may be in other values than C/I values. However, it is also obvious that C/I values are quite advantageous input parameters since they can be established by means of existing analysis and optimalization means.

According to the shown embodiment, it is thus possible, at least in principle, to input any combination of C/I values corresponding to a determined or read reality at a given location, after which RB will create an estimate of quality, EOQ, reflecting the actual prevailing signal quality at the given location. According to the preferred embodiment, the EOQ will constitute the Frame Erasure Rate, FER, since this value is established subsequent to the decoding of a GSM signal at a receiver and since it is a value that can be directly extracted from the GSM protocol.

It is implicit that the RB may be appropriately quantified into a number of discrete values in such a manner that the input sets SI, S2, S3, S4, ...., Sn may be transferred to these by a limited quantification. The less quantification, the bigger the reference base.

In this instance, the reference base is established by means of a link-simulator comprising three basic algorithms. The first algorithm simulates a GSM transmitter, the second algorithm simulates an environment and its surrounding network (e.g. interfering adjacent base stations) and the third simulates a GSM receiver. It is implicit that a good link-simulator may be of great advantage to the invention.

It is also implicit that other estimates of quality may be advantageously applied as long as these are established subsequent to the channel decoding.

Thus, according to the invention, it is particularly important that the channel decoding is included in a link-simulation as this process saves and regenerates a considerable amount of data bits. This recovery is particularly significant in relation to a frequency hopping network since a GSM network such as the one mentioned above obtains a significantly improved signal quality under certain circumstances.

An example of such an obvious improvement may be if e.g. two channels, CHI and CH2, have a high C/I value while CH3 has a very low value, e.g. below 10 dB.

Without frequency hopping, this means that CH3 will practically be useless under bad radio conditions where the subscriber at this location will not be provided with a quality good enough to make communication possible.

If frequency hopping is applied, the transmissions on channels CHI, CH2 and CH3 may take advantage of the fact that each burst generated by a given signal is transmitted alternately on each channel whereby a channel with relatively poor radio conditions will in reality be masked. A measure for the value of this masking will necessarily have to be made subsequent to the decoding of the individual speech channels.

It is implicit that the invention may also be supplemented by numerical representations for C/A etc.

Figure 7 illustrates the frequency allocation chart illustrated in figure 2 but this time, the calculations have been made in accordance with the invention. The result clearly shows that the number and extent of items poorly serviced or with a poor quality has been reduced significantly which means that the allocator is not required to carry out various improvements of the network as the frequency allocation chart originally indicated in accordance with the existing technique.

In this manner, all false adhesions have been excluded and this provides a system planner with the opportunity to carry out network optimalization processes with a much higher degree of freedom.

In the above-mentioned embodiment, the estimate of quality has been established by the use of e.g. a Frame Erasure Rate, FER. Meanwhile, it should be stressed that the estimate of quality, according to the invention, may also be established by other means of expressing data quality, incl. combinations of FER and these quality expressing data such as FER and a Bit Error Rate, BER.

Claims

Patent Claims

1. Method of establishing at least one quality estimate in a communication network for one or more sets (SI, S2, S3, S4, ...., Sn) of possible signal representations for each radio frequency in a given combination of a number of various radio frequencies (CH 1 , CH2, ...., CHn),

wherein each set has been provided with a given estimate of quality (EOQ) for the signal quality of a signal received by a receiver (BSS, MS), said estimate of quality being a quality measure for a decoded signal received at a receiving unit (BSS, MS) in a network.

2. Method according to claim Icharacterized by the possible signal representations for each radio frequency in a given combination of radio frequencies (CHI, CH2, ..., CHn) being specified to a certain location

where each set has been provided with a given estimate of quality (EOQ) for the signal quality of a signal received by a receiver (BSS, MS) at the said location

3. Method according to claim Icharacterized by the network being a frequency hopping FH network

4. Method according to claim I characterized by the estimate of quality being stated as a Frame Erasure Rate.

5. Means for allocation of radio frequencies in a network comprising

a reference base (RB) consisting of one or more sets (SI, S2, S3, S4, ...., Sn) of possible signal representations for each radio frequency in a given combination of a number of various radio frequencies (CHI, CH2, ....,

CHn), wherein each set has been provided with a given estimate of quality (EOQ) for the signal quality of a signal received by a receiver (BSS, MS), said estimate of quality being a quality measure for a decoded signal received at a receiving unit (BSS, MS) in a network.

6. Means according to claim Icharacterized by the possible signal representations for each radio frequency in a given combination of radio frequencies (CHI, CH2, ..., CHn) being specified to a certain location

where each set has been provided with a given estimate of quality (EOQ) for the signal quality of a signal received by a receiver (BSS, MS) at the said location.

7. Means according to claim l or2characterized by the number representations being made up by C/I values or strongly correlating measures for BER.

8. Means according to claims lto3characterized by the estimate of quality being stated as a Frame Erasure Rate.

9. Means according to claims lto4characterized by the estimate of quality being established by means of a link-simulator simulating the radio interface between a base station (BSS) and a mobile subscriber (MS).

10. Means according to claims lto5characterized by the estimate of quality being established by means of a listening test.

11. Means according to claims l toόcharacterized by the network being a frequency hopping FH network.

12. Means according to claims lto7characterized by the estimate of quality (EOQ) being weighed with the digital and acoustical properties of various cellular phone brands.

13. Method of establishing one or more quality of service (QOS) estimates related to one or more sets (SI, S2, ..., Sn) of possible signal representations for each radio frequency in a given combination of radio frequencies (CHI , CH2, ..., CHn) of a given communication network char acterized by each of the QOS estimates being established as an EOQ estimate referring to the signal quality of a decoded signal at a receiver in a network when the conditions are described by one of the said corresponding sets (SI, S2, ..., Sn).

14. Method according to claim 9 c h ar a c t e r i z e d b y the mobile communication network being a GSM network.

15. Method according to claim 9 or 10 characterized by the EOQ estimate constituting the Frame Erasure Rate, FER.

16. Method according to claims 9 to 11 characterized by the EOQ values being established from the input of a number of sets (SI, S2, ..., Sn) in a link-simulator.

17. Method for allocation of carrier frequencies in a radio network c h a r a c t e r i z e d b y said frequencies being allocated in dependency of EOQ as established on the basis of the content of claim 1-16.