[go: up one dir, main page]

WO2006118539A2 - Method for handling signal quality measurements in a wireless communication system - Google Patents

Method for handling signal quality measurements in a wireless communication system Download PDF

Info

Publication number
WO2006118539A2
WO2006118539A2 PCT/SE2006/050088 SE2006050088W WO2006118539A2 WO 2006118539 A2 WO2006118539 A2 WO 2006118539A2 SE 2006050088 W SE2006050088 W SE 2006050088W WO 2006118539 A2 WO2006118539 A2 WO 2006118539A2
Authority
WO
WIPO (PCT)
Prior art keywords
terminal
base station
processing rules
recommended
measurement reports
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/SE2006/050088
Other languages
French (fr)
Other versions
WO2006118539A3 (en
Inventor
Jonas Karlsson
David Astely
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Telefonaktiebolaget LM Ericsson AB
Original Assignee
Telefonaktiebolaget LM Ericsson AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Telefonaktiebolaget LM Ericsson AB filed Critical Telefonaktiebolaget LM Ericsson AB
Publication of WO2006118539A2 publication Critical patent/WO2006118539A2/en
Publication of WO2006118539A3 publication Critical patent/WO2006118539A3/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0023—Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the signalling
    • H04L1/0026—Transmission of channel quality indication
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B17/00—Monitoring; Testing
    • H04B17/20—Monitoring; Testing of receivers
    • H04B17/24—Monitoring; Testing of receivers with feedback of measurements to the transmitter
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B17/00—Monitoring; Testing
    • H04B17/30—Monitoring; Testing of propagation channels
    • H04B17/309—Measuring or estimating channel quality parameters
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems

Definitions

  • the present invention relates to a method for handling signal quality measurements in a wireless communication system.
  • the quality of the communication links is repeatedly measured. Measurement signals are sent from the base stations to the terminals in the downlink and from the terminals to the base stations in the uplink. The quality of these measurement signals is measured and measurement reports are generated and sent back to the base station or the terminal.
  • the measurement reports could comprise quality measurements for both different times and different frequencies and also for different transmit antennas or linear combinations of transmit antennas, referred to as beams, if multiple transmit antennas are used.
  • beams linear combinations of transmit antennas
  • To decrease the number of measurement reports averaging over certain time spans is used in for example GSM. The time spans that should be used for the averaging are defined in the standard. Additionally, wideband wireless systems may exploit also the frequency dimension and the spatial dimension.
  • An object of the invention is to provide an improved system for handling quality measurements.
  • a method, a terminal and a base station are achieved where the rules for the generation of measurement reports are adjusted based on current conditions experienced in the terminal. This implies that the measurement reports can be made more or less detailed depending on what is needed for the actual situation. This gives a flexible system where capacity can be saved.
  • the method can be applied both for uplink and downlink.
  • recommended pre-processing rules are sent from the base station to the terminal where the rules are adjusted.
  • the adjustments are then preferably reported to the base station.
  • the base station knows which pre-processing rules to use in the uplink and the base station can understand the measurement reports sent to the base station for the downlink.
  • recommended pre-processing rules are sent from the terminal to the base station where the rules are adjusted.
  • the adjustments are suitably reported to the terminal.
  • the adjusting of the pre-processing rules is performed such that measurement reports are provided as a function of the measured signal quality for a certain span of frequencies and/or time and/or antennas or beams of an array antenna.
  • the number of measurement reports can be varied.
  • the current conditions experienced by the terminal include the velocity of the terminal and/or the time dispersion and/or the spatial correlation of the radio channel between the base station antennas or beams and the terminal and/or the bit rate required by the terminal.
  • Fig. Ia shows schematically a terminal according to one embodiment of the invention.
  • Fig. Ib shows schematically a base station according to one embodiment of the invention.
  • Fig. Ic shows schematically a base station according to another embodiment of the invention.
  • Fig. 2a is a flow chart of one embodiment of the invention in the downlink direction.
  • Fig. 2b is a flow chart of one embodiment of the invention in the uplink direction.
  • TDMA time-division multiple-access
  • FDMA frequency-division multiple-access
  • CDMA code-division multiple-access
  • TDM time-division multiplex
  • FDM frequency-division multiplex
  • CDMA code-division multiplex
  • OFDM orthogonal-frequency-division multiplex
  • the invention is carried out in a wireless communication system where terminals communicate through base stations.
  • the communication between one terminal and one base station will now be described in more detail.
  • the terminal could for example be a mobile telephone, a fixed access terminal or remote measurement/steering devices.
  • the base station could be an array antenna base station or a single antenna base station.
  • a measurement signal is sent from the base station to the terminal in the downlink communication and from the terminal to the base station in the uplink communication.
  • the measurement signal can be sent continuously from the base station to the terminal.
  • the terminal however usually sends the measurement signal together with ordinary data. Other methods and intervals for sending the measurement signal in both downlink and uplink are however also possible.
  • the downlink is now described in more detail.
  • the terminal measures the quality of the measurement signal in order to return measurement reports with signal quality information to the base station.
  • the terminal measures the quality of the measurement signal both at different points in time and for different frequencies.
  • the base station comprises multiple transmit antennas the terminal can measure the quality of signals transmitted directly from the antennas, signals transmitted in beams with different antenna specific transmit weights, or linear combinations of received signals transmitted from different antennas.
  • the measurement signals must not necessarily be transmitted directly from the physical antennas but may be subject to beamforming, either at the transmitter or the receiver. If a measurement report should be sent for each measured time and frequency and also for each antenna or beam, there would be a very large amount of measurement reports to be sent.
  • the base station provides the terminals with pre-processing rules. These rules are instructions to the terminals of how the measurement reports should be generated regarding for example the sizes of time spans and frequency spans for the averaging as well as the type of averaging, such as linear or logarithmic averaging. If the base station has multiple antennas instructions as to whether the measurement reports should be average measurements of all the antennas or beams, or separate measurement reports for each antenna or beam should be included in the pre-processing rules. Further, instructions for calculating interference between the antennas or beams may also be part of the pre-processing rules. The pre-processing rules could be repeatedly broadcasted out to all the terminals and/or provided to each terminal in the setting up procedure for the connection.
  • the terminal can according to the invention adjust the pre-processing rules sent from the base station according to current conditions experienced by the terminal. Therefore we will hereafter denote the preprocessing rules sent from the base station as recommended pre-processing rules and the finally used pre-processing rules as adjusted pre-processing rules.
  • the terminal comprises hereby according to the invention means for measuring the current conditions and means for adjusting the recommended pre-processing rules accordingly.
  • the current conditions could be for example the movement of the terminal, the time dispersion of the radio channel, the bit rate required by the terminal and/or the spatial correlation between different antennas or beams if the base station has multiple antennas.
  • Downlink was described above but the invention is also applicable in uplink.
  • the difference is that for uplink the terminal sends measurement signals to the base station.
  • the base station measures these signals and returns measurement reports comprising average values as described above.
  • the recommended pre-processing rules are set as for downlink in the base station.
  • the recommended pre-processing rules are either broadcasted to the terminals as described above or forwarded during communication set up.
  • the terminal adjusts these recommended pre-processing rules according to the current conditions experienced by the terminal in the same way as for downlink.
  • the adjusted pre-processing rules are returned to the base station and the base station uses these adjusted pre-processing rules for the averaging of the measurements when generating measurement reports.
  • the terminal can also have multiple antennas and this will be treated in the same way as the multiple antennas of the base station for the downlink communication.
  • the terminal sets the recommended pre-processing rules and the base station adjusts them.
  • the adjustment is also in this embodiment based on the current conditions experienced in the terminal. These current conditions are the same as described above and can be retrieved in the base station by for example measuring the measuring signals sent from the terminal.
  • the adjustments are preferably forwarded to the terminal such that the terminal always is aware of which pre-processing rules that are used in the base station.
  • the recommended pre-processing rules are already provided in the base station and they are adjusted in the base station as described above. These already provided rules are called basic recommended pre-processing rules.
  • the pre-processing rules comprise beside the averaging rules also rules for the reporting, e.g. how many bites the measurement reports should comprise and if one or both of amplitude and phase should be reported. Also these rules can be adjusted in the terminal according to current conditions as described above. For example advanced transmit and receive algorithms in the terminal and the base station will benefit from more detailed measurement reports.
  • pre-processing rules only are distributed individually to the different terminals (no broadcasting) it is possible to send different recommended pre-processing rules to different terminals. This could be beneficial if the base station is aware of the needs and the capabilities of the terminals.
  • basic recommended pre-processing rules are provided in the terminals. These rules are used as recommended pre-processing rules if no recommended pre-processing rules are sent from the base station or before any recommended pre-processing rules have been received in the terminal.
  • a terminal according to one embodiment of the invention is schematically illustrated.
  • a mobile telephone is illustrated but as discussed above it could also be for example a fixed access terminal or remote measurement/steering devices.
  • the mobile telephone comprises of course many other components such as for example a microphone, a speaker, a memory, a key pad and a processor.
  • An antenna 21 is shown connected to a communication means 23.
  • the communication means controls the transmitting and receiving of signals from and to the mobile telephone.
  • a first measuring means 25 is connected to the communication means 23 and adapted to measure one or more of the current conditions experienced by the mobile telephone as discussed above.
  • Adjusting means 27 is connected to the first measuring means 25 and to the communication means.
  • the adjusting means 27 is adapted to receive recommended pre-processing rules from base stations through the antenna 21 and the communication means 23. Furthermore the adjusting means 27 retrieves measurement results regarding current conditions from the first measuring means 25.
  • the adjusting means 27 is adapted to adjust the recommended pre-processing rules according to the measurement results regarding for example terminal velocity, bit rate requirements, time dispersion, spatial correlation in the case with multiple transmit antennas and optionally also according to information about the mobile telephone capacity. If for example this specific mobile telephone is a simple telephone with small processing capacity and less advanced transmit means the adjusting means 27 can adjust the pre-processing rules such that very few measurement reports have to be sent. The rules are preferably adjusted such that fewer measurement reports are created. This could be achieved by increasing the time and frequency spans for averaging. However the time and frequency resolution of the reports does not need to be reduced. The number of reports can instead be reduced by simply not report for all time and frequency intervals.
  • a second measuring means 28 is connected to the communication means 23 and adapted to measure the quality of the measurement signals coming from the base stations. Measurements are normally made for different frequencies and different times. If multiple transmit antennas are used in the base station the second measuring means 28 will also perform measurements for the measurement signals being sent from different antennas or in different beams.
  • a measurement report generating means 29 is connected to the second measuring means 28, the adjusting means 27 and to the communication means 23. The measurement report generating means 29 is adapted to generate measurement reports according to the adjusted pre-processing rules using the measurements from the second measuring means 28.
  • the adjusted pre-processing rules can say that the measurement reports should be based on averages of different time spans and different frequency spans and possibly also averages of all the antennas or all beams for the case with a multiple antenna base station.
  • the pre-processing rules define these spans. To decrease the number of reports the spans should be made larger. However, under certain circumstances it could for example be advantageous to have a small span in frequency and a large span in time. This could for example be beneficial when the terminal's velocity is low and the radio channel's time dispersion is not too large.
  • each measurement report created in the measurement report generating means 29 is a value of the quality of the communication link for a certain defined frequency span under a certain defined time period and possibly also an average of signals from different antennas or different beams when multiple transmit antennas are used.
  • the adjustments made to the recommended pre-processing rules need to be reported to the base station such that the base station can understand the measurement reports.
  • a reporting means 30 has been illustrated in Figure 1. It is connected to the adjusting means 27 and the communication means 23 and is adapted to report adjustments to the base station every time the rules are adjusted. This report can possibly also be included in the measurement reports.
  • the benefits provided by the invention are that the number of measurement reports can be decreased if the terminal recognises that the number of measurement reports recommended by the base station is unnecessarily large. If the number of measurement reports can be decreased without affecting the quality it is beneficial to the whole system. Furthermore with this invention the terminal is given more responsibility and hereby the base stations can be made less complex.
  • the process can also be applied for the uplink communication, i.e. from terminal to base station.
  • the terminal receives recommended pre-processing rules from the base station and these rules are adjusted in the adjusting means 27 as described above in dependence of measurements performed in the first measuring means 25 and possibly also in dependence of other terminal conditions such as required bit rate and terminal capacity.
  • the adjusted pre-processing rules are then reported to the base station where the base station uses the adjusted pre-processing rules to generate measurement reports.
  • the terminal sets the recommended pre-processing rules and the base station adjusts the processing rules as described above.
  • a base station according to one embodiment of the invention is shown in Figure Ib. Only the parts that are needed for the inventive steps are illustrated in Fig Ib.
  • the base station comprises of course many other components involved in the normal functions of the base station.
  • the base station comprises an antenna 31 which as described above could comprise multiple transmit antennas.
  • the base station comprises furthermore a base station communication means 33 connected to the antenna and adapted to control the transmitting and receiving of signals from and the base station.
  • a base station pre-processing rules managing means 35 is connected to the base station communication means 33.
  • the base station pre-processing managing means 35 is adapted to send recommended pre-processing rules through the base station communication means 33 to the terminals.
  • the base station preprocessing rules managing means 35 is further adapted to receive the adjustments made to the pre-processing rules in the terminal.
  • a base station measurement report generating means 37 which is connected to the base station pre-processing rules managing means 35 and to the base station communication means 33 and further also to a base station measuring means 39 adapted to measure measuring signals sent from the terminals uses the adjusted preprocessing rules to generate measurement reports accordingly.
  • a terminal can in another embodiment send recommended pre-processing rules to the base station (and/or basic recommended pre-processing rules are already provided in the base station) and the base station adjusts these rules.
  • This embodiment is schematically illustrated in Fig Ic.
  • a terminal current condition measuring means 41 is provided between the communication means 33 and the base station pre-processing rules managing means 35.
  • the terminal current condition measuring means 41 is adapted to measure the current state of the terminal. This could for example be done by measuring the measuring signals sent from the terminal.
  • the base station pre-processing rules managing means 35 is adapted to adjust the recommended pre-processing rules according to the current states measured in the terminal current condition measuring means 41.
  • a base station reporting means 43 is also provided between the base station pre-processing rules managing means 35 and the base station communication means 33 and is adapted to report any adjustments made to the pre-processing rules to the terminal. As in the first described embodiment the base station measurement report generating means 37 generates measurement reports according to the adjusted pre-processing rules.
  • the base stations provide recommended pre-processing rules that are restricted to the maximum capacity of the base station, i.e. rules advising to perform averaging in the terminal that will generate a maximum number of measurement reports that the base station can handle.
  • the adjustment of the rules in the terminal is then restricted to adjust the rules such that the number of measurement reports is decreased.
  • FIG 2a and 2b flow charts of the process steps according to one embodiment of the invention where the adjustments are made in the terminal is shown.
  • the velocity of the terminal is measured in the terminal and used for adjusting the recommended pre-processing rules.
  • the bit rate required by the terminal is also used to adjust the rules.
  • the downlink is described in Figure 2a and the uplink in Figure 2b.
  • a measurement signal is continuously sent from the base station to the terminal for the downlink and for the uplink a measurement signal is continuously sent from the terminal to the base station.
  • the measurement signal could instead of being sent continuously be sent together with ordinary data.
  • Dl A terminal enters the cell of a base station or the terminal is turned on inside the cell.
  • a communication channel is set up between the terminal and the base station.
  • D5 During this channel setting up the base station in this embodiment also sends recommended pre-processing rules to the terminal.
  • the pre-processing rules give instructions to the terminal how the measurement reports should be generated regarding for example averaging of the measured signal quality over different time and frequency spans.
  • a first measuring means in the terminal measures in this embodiment the velocity of the terminal.
  • An adjusting means in the terminal receives the velocity measurements and the recommended pre-processing rules and is adapted to adjust the recommended pre-processing rules in dependence of the velocity.
  • the adjustment should in this embodiment also be dependent on the bit rate required by the terminal.
  • the information of required bit rate is provided to the adjusting means from the scheduler in the terminal.
  • the recommended pre-processing rules can be adjusted such that the number of measurement reports in the time domain is decreased if the velocity is very low, i.e. the terminal is stationary or close to stationary. It could also be advantageous to decrease the number of measurement reports if the velocity of the terminal is very high since in that case there is no meaning with very detailed measurement reports due to the fast changes on the radio channel and the time delay between the quality measurements and the use of the measurements in the base station.
  • the recommended pre-processing rules could be adjusted such that the number of measurement reports is further decreased.
  • the number of measurement reports could be advantageous to decrease the number of measurement reports by only reporting quality for a fraction of the available bandwidth and/or time intervals instead of changing the frequency and time spans for the averaging.
  • the terminal generates measurement reports according to the adjusted pre-processing rules, i.e. for example averaging the quality measurements over the frequency and time spans that are defined in the adjusted pre-processing rules or reporting only for certain frequency and/or time fractions. If multiple transmit antennas are used in this base station the averaging can also be over all or a subset of the antennas or beams of the array antenna.
  • the adjusted pre-processing rules i.e. for example averaging the quality measurements over the frequency and time spans that are defined in the adjusted pre-processing rules or reporting only for certain frequency and/or time fractions. If multiple transmit antennas are used in this base station the averaging can also be over all or a subset of the antennas or beams of the array antenna.
  • the measurement reports are returned to the base station together with information of the adjustments made to the recommended pre-processing rules.
  • the base station need to know which pre-processing rules that have been used in order to be able to read the reports.
  • step D9 for measuring a new velocity of the terminal and then the originally sent recommended pre-processing rules are adjusted according to the new velocity and possibly also a new required bit rate.
  • the recommended preprocessing rules are adjusted repeatedly and so often that a new adjustment has been performed each time new measurement reports are sent to the base station.
  • the adjustment of the pre-processing rules and the transmission of measurement reports do not need to be done with the same rate.
  • a terminal enters the cell of a base station or the terminal is turned on inside the cell.
  • U3 A communication channel is set up between the terminal and the base station.
  • the pre-processing rules give instructions how the measurement reports should be generated regarding for example averaging of the measured signal quality over different time and frequency spans.
  • a first measuring means in the terminal measures in this embodiment the velocity of the terminal.
  • An adjusting means in the terminal receives the velocity measurements and the recommended pre-processing rules and is adapted to adjust the recommended pre-processing rules in dependence of the velocity and the bit rate as described above for the downlink.
  • the base station generates measurement reports according to the adjusted pre-processing rules, i.e. averaging the quality measurements over the' frequency and time spans that are defined in the adjusted pre-processing rules. If multiple transmit antennas are used in this terminal the averaging can also be over all or a subset of the antennas or beams of the antennas.
  • the process is then started again from U9.
  • the frequency for the adjustments of the recommended pre-processing rules can vary but in this example the rules are adjusted every time measurement reports are sent as described above for the downlink.
  • the terminal has adjusted the pre-processing rules such that the quality only is measured by the base station in certain intervals of frequency and/or time the terminal need only to send measurement signals for those intervals that should be measured. This will reduce the power consumption in the terminal and reduce the interference in the system.

Landscapes

  • Engineering & Computer Science (AREA)
  • Quality & Reliability (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

A method, a terminal and a base station for handling signal quality measurements in a wireless communication system comprising at least one base station communicating with at least one terminal. According to the invention the method comprises adjusting recommended pre-processing rules for the generation of measurement reports, where said measurement reports comprises signal quality feedback information, said adjusting being based on current conditions experienced in the terminal.

Description

A method in a wireless communication system
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for handling signal quality measurements in a wireless communication system.
BACKGROUND OF THE INVENTION
In wireless communication systems the quality of the communication links is repeatedly measured. Measurement signals are sent from the base stations to the terminals in the downlink and from the terminals to the base stations in the uplink. The quality of these measurement signals is measured and measurement reports are generated and sent back to the base station or the terminal. The measurement reports could comprise quality measurements for both different times and different frequencies and also for different transmit antennas or linear combinations of transmit antennas, referred to as beams, if multiple transmit antennas are used. To decrease the number of measurement reports averaging over certain time spans is used in for example GSM. The time spans that should be used for the averaging are defined in the standard. Additionally, wideband wireless systems may exploit also the frequency dimension and the spatial dimension.
Development of new technologies motivates more measurement reports, but it will not be able to use these new technologies for all scenarios. Depending on the channel, interference and traffic conditions, different degrees of adaptivity in the three dimensions may be adequate and this requires suitable measurement reports. In the general case, measurement reports with high granularity in all the dimensions may be generated for transfer to the base station and terminal respectively. Clearly, always transferring such detailed reports does not make sense from an efficiency point of view if the adaptivity anyway not is exploited since the transfer requires a lot of capacity.
SUMMARY
An object of the invention is to provide an improved system for handling quality measurements.
i This is achieved in a method according to claim 1, in a terminal according to claim 12 and in a base station according to claim 19 or 20.
Hereby a method, a terminal and a base station are achieved where the rules for the generation of measurement reports are adjusted based on current conditions experienced in the terminal. This implies that the measurement reports can be made more or less detailed depending on what is needed for the actual situation. This gives a flexible system where capacity can be saved.
The method can be applied both for uplink and downlink.
In one embodiment recommended pre-processing rules are sent from the base station to the terminal where the rules are adjusted. The adjustments are then preferably reported to the base station. Hereby the base station knows which pre-processing rules to use in the uplink and the base station can understand the measurement reports sent to the base station for the downlink.
In another embodiment recommended pre-processing rules are sent from the terminal to the base station where the rules are adjusted. The adjustments are suitably reported to the terminal.
Preferably the adjusting of the pre-processing rules is performed such that measurement reports are provided as a function of the measured signal quality for a certain span of frequencies and/or time and/or antennas or beams of an array antenna. Hereby the number of measurement reports can be varied.
Suitably the current conditions experienced by the terminal include the velocity of the terminal and/or the time dispersion and/or the spatial correlation of the radio channel between the base station antennas or beams and the terminal and/or the bit rate required by the terminal.
Further suitable embodiments are disclosed in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS
Fig. Ia shows schematically a terminal according to one embodiment of the invention.
Fig. Ib shows schematically a base station according to one embodiment of the invention.
Fig. Ic shows schematically a base station according to another embodiment of the invention.
Fig. 2a is a flow chart of one embodiment of the invention in the downlink direction.
Fig. 2b is a flow chart of one embodiment of the invention in the uplink direction.
DETAILED DESCRIPTION OF THE EMBODIMENTS
The following description is applicable to any multiple access schemes (e.g. time-division multiple-access (TDMA), frequency-division multiple-access (FDMA) and code-division multiple-access (CDMA)) as well as to any multiplexing scheme (e.g. time-division multiplex (TDM), frequency-division multiplex (FDM), code-division multiplex (CDM) and orthogonal-frequency-division multiplex (OFDM)).
The invention is carried out in a wireless communication system where terminals communicate through base stations. The communication between one terminal and one base station will now be described in more detail. The terminal could for example be a mobile telephone, a fixed access terminal or remote measurement/steering devices. The base station could be an array antenna base station or a single antenna base station. During the communication a measurement signal is sent from the base station to the terminal in the downlink communication and from the terminal to the base station in the uplink communication. The measurement signal can be sent continuously from the base station to the terminal. The terminal however usually sends the measurement signal together with ordinary data. Other methods and intervals for sending the measurement signal in both downlink and uplink are however also possible. The downlink is now described in more detail. The terminal measures the quality of the measurement signal in order to return measurement reports with signal quality information to the base station. There are a number of different possible ways to process the measurement results to generate measurement reports. The terminal measures the quality of the measurement signal both at different points in time and for different frequencies. Furthermore if the base station comprises multiple transmit antennas the terminal can measure the quality of signals transmitted directly from the antennas, signals transmitted in beams with different antenna specific transmit weights, or linear combinations of received signals transmitted from different antennas. Thus, the measurement signals must not necessarily be transmitted directly from the physical antennas but may be subject to beamforming, either at the transmitter or the receiver. If a measurement report should be sent for each measured time and frequency and also for each antenna or beam, there would be a very large amount of measurement reports to be sent. This requires capacity from the terminal and uplink transmission link. Therefore it is advantageous to perform averaging of the measurements. It could be averaging both over a time span and over a frequency span. Furthermore it is possible to calculate an average quality measure over the different antennas or different beams in the case with multiple transmit antennas. This averaging could be a simple arithmetic mean, but could also be a more general function in order to optimise the accuracy of the measurements.
The base station provides the terminals with pre-processing rules. These rules are instructions to the terminals of how the measurement reports should be generated regarding for example the sizes of time spans and frequency spans for the averaging as well as the type of averaging, such as linear or logarithmic averaging. If the base station has multiple antennas instructions as to whether the measurement reports should be average measurements of all the antennas or beams, or separate measurement reports for each antenna or beam should be included in the pre-processing rules. Further, instructions for calculating interference between the antennas or beams may also be part of the pre-processing rules. The pre-processing rules could be repeatedly broadcasted out to all the terminals and/or provided to each terminal in the setting up procedure for the connection.
In order to be able to decrease the number of measurement reports further the terminal can according to the invention adjust the pre-processing rules sent from the base station according to current conditions experienced by the terminal. Therefore we will hereafter denote the preprocessing rules sent from the base station as recommended pre-processing rules and the finally used pre-processing rules as adjusted pre-processing rules. The terminal comprises hereby according to the invention means for measuring the current conditions and means for adjusting the recommended pre-processing rules accordingly. The current conditions could be for example the movement of the terminal, the time dispersion of the radio channel, the bit rate required by the terminal and/or the spatial correlation between different antennas or beams if the base station has multiple antennas. If for example a terminal is travelling at great velocity it would maybe not be relevant with many measurement reports during this transport since the conditions will change rapidly. Furthermore high time dispersion causes the quality of the radio channel to vary very quickly in the frequency domain. If the frequency span for a measurement report is large compared to variations, there will be small differences in quality between different frequency spans. Therefore averaging over the whole frequency band can instead be made. If the bit rate required by the terminal is low it will furthermore be unnecessary to send measurement reports for all frequency intervals, since only a small fraction of the total frequency band would be needed to transmit the low bit rate signal. If the spatial correlation between antennas or beams is very high, it will be enough to report the correlation of one antenna or beam. This will be described in more detail below with reference to Figures 1, 2a and 2b.
Downlink was described above but the invention is also applicable in uplink. The difference is that for uplink the terminal sends measurement signals to the base station. The base station measures these signals and returns measurement reports comprising average values as described above. In this case the recommended pre-processing rules are set as for downlink in the base station. The recommended pre-processing rules are either broadcasted to the terminals as described above or forwarded during communication set up. The terminal adjusts these recommended pre-processing rules according to the current conditions experienced by the terminal in the same way as for downlink. The adjusted pre-processing rules are returned to the base station and the base station uses these adjusted pre-processing rules for the averaging of the measurements when generating measurement reports. The terminal can also have multiple antennas and this will be treated in the same way as the multiple antennas of the base station for the downlink communication.
In an alternative embodiment the terminal sets the recommended pre-processing rules and the base station adjusts them. The adjustment is also in this embodiment based on the current conditions experienced in the terminal. These current conditions are the same as described above and can be retrieved in the base station by for example measuring the measuring signals sent from the terminal. The adjustments are preferably forwarded to the terminal such that the terminal always is aware of which pre-processing rules that are used in the base station.
In a further alternative embodiment the recommended pre-processing rules are already provided in the base station and they are adjusted in the base station as described above. These already provided rules are called basic recommended pre-processing rules.
In one embodiment of the invention the pre-processing rules comprise beside the averaging rules also rules for the reporting, e.g. how many bites the measurement reports should comprise and if one or both of amplitude and phase should be reported. Also these rules can be adjusted in the terminal according to current conditions as described above. For example advanced transmit and receive algorithms in the terminal and the base station will benefit from more detailed measurement reports.
If the pre-processing rules only are distributed individually to the different terminals (no broadcasting) it is possible to send different recommended pre-processing rules to different terminals. This could be beneficial if the base station is aware of the needs and the capabilities of the terminals.
In one embodiment of the invention basic recommended pre-processing rules are provided in the terminals. These rules are used as recommended pre-processing rules if no recommended pre-processing rules are sent from the base station or before any recommended pre-processing rules have been received in the terminal.
In Figure Ia a terminal according to one embodiment of the invention is schematically illustrated. In this example a mobile telephone is illustrated but as discussed above it could also be for example a fixed access terminal or remote measurement/steering devices. In Figure 1 only the parts that are needed for the inventive steps have been illustrated. The mobile telephone comprises of course many other components such as for example a microphone, a speaker, a memory, a key pad and a processor. An antenna 21 is shown connected to a communication means 23. The communication means controls the transmitting and receiving of signals from and to the mobile telephone. A first measuring means 25 is connected to the communication means 23 and adapted to measure one or more of the current conditions experienced by the mobile telephone as discussed above. The velocity, time dispersion and spatial correlation can for example be estimated from the measurement signals or from any other signals transmitted from the base station that can be used to estimate the radio channel's properties. A scheduler in the terminal that passes data from the terminal's applications to the communication means can estimate the data rate needs. Adjusting means 27 is connected to the first measuring means 25 and to the communication means. The adjusting means 27 is adapted to receive recommended pre-processing rules from base stations through the antenna 21 and the communication means 23. Furthermore the adjusting means 27 retrieves measurement results regarding current conditions from the first measuring means 25. The adjusting means 27 is adapted to adjust the recommended pre-processing rules according to the measurement results regarding for example terminal velocity, bit rate requirements, time dispersion, spatial correlation in the case with multiple transmit antennas and optionally also according to information about the mobile telephone capacity. If for example this specific mobile telephone is a simple telephone with small processing capacity and less advanced transmit means the adjusting means 27 can adjust the pre-processing rules such that very few measurement reports have to be sent. The rules are preferably adjusted such that fewer measurement reports are created. This could be achieved by increasing the time and frequency spans for averaging. However the time and frequency resolution of the reports does not need to be reduced. The number of reports can instead be reduced by simply not report for all time and frequency intervals.
A second measuring means 28 is connected to the communication means 23 and adapted to measure the quality of the measurement signals coming from the base stations. Measurements are normally made for different frequencies and different times. If multiple transmit antennas are used in the base station the second measuring means 28 will also perform measurements for the measurement signals being sent from different antennas or in different beams. A measurement report generating means 29 is connected to the second measuring means 28, the adjusting means 27 and to the communication means 23. The measurement report generating means 29 is adapted to generate measurement reports according to the adjusted pre-processing rules using the measurements from the second measuring means 28. For example the adjusted pre-processing rules can say that the measurement reports should be based on averages of different time spans and different frequency spans and possibly also averages of all the antennas or all beams for the case with a multiple antenna base station. The pre-processing rules define these spans. To decrease the number of reports the spans should be made larger. However, under certain circumstances it could for example be advantageous to have a small span in frequency and a large span in time. This could for example be beneficial when the terminal's velocity is low and the radio channel's time dispersion is not too large. Hereby each measurement report created in the measurement report generating means 29 is a value of the quality of the communication link for a certain defined frequency span under a certain defined time period and possibly also an average of signals from different antennas or different beams when multiple transmit antennas are used. The adjustments made to the recommended pre-processing rules need to be reported to the base station such that the base station can understand the measurement reports. A reporting means 30 has been illustrated in Figure 1. It is connected to the adjusting means 27 and the communication means 23 and is adapted to report adjustments to the base station every time the rules are adjusted. This report can possibly also be included in the measurement reports.
The benefits provided by the invention are that the number of measurement reports can be decreased if the terminal recognises that the number of measurement reports recommended by the base station is unnecessarily large. If the number of measurement reports can be decreased without affecting the quality it is beneficial to the whole system. Furthermore with this invention the terminal is given more responsibility and hereby the base stations can be made less complex.
As already discussed above, the process can also be applied for the uplink communication, i.e. from terminal to base station. The terminal receives recommended pre-processing rules from the base station and these rules are adjusted in the adjusting means 27 as described above in dependence of measurements performed in the first measuring means 25 and possibly also in dependence of other terminal conditions such as required bit rate and terminal capacity. The adjusted pre-processing rules are then reported to the base station where the base station uses the adjusted pre-processing rules to generate measurement reports. Alternatively, the terminal sets the recommended pre-processing rules and the base station adjusts the processing rules as described above.
A base station according to one embodiment of the invention is shown in Figure Ib. Only the parts that are needed for the inventive steps are illustrated in Fig Ib. The base station comprises of course many other components involved in the normal functions of the base station. The base station comprises an antenna 31 which as described above could comprise multiple transmit antennas. The base station comprises furthermore a base station communication means 33 connected to the antenna and adapted to control the transmitting and receiving of signals from and the base station. A base station pre-processing rules managing means 35 is connected to the base station communication means 33. The base station pre-processing managing means 35 is adapted to send recommended pre-processing rules through the base station communication means 33 to the terminals. The base station preprocessing rules managing means 35 is further adapted to receive the adjustments made to the pre-processing rules in the terminal. For the downlink communication the base station uses these adjusted pre-processing rules to understand the measurement reports received from the terminal. For the uplink communication a base station measurement report generating means 37 which is connected to the base station pre-processing rules managing means 35 and to the base station communication means 33 and further also to a base station measuring means 39 adapted to measure measuring signals sent from the terminals uses the adjusted preprocessing rules to generate measurement reports accordingly.
As mentioned above a terminal can in another embodiment send recommended pre-processing rules to the base station (and/or basic recommended pre-processing rules are already provided in the base station) and the base station adjusts these rules. This embodiment is schematically illustrated in Fig Ic. In this embodiment a terminal current condition measuring means 41 is provided between the communication means 33 and the base station pre-processing rules managing means 35. The terminal current condition measuring means 41 is adapted to measure the current state of the terminal. This could for example be done by measuring the measuring signals sent from the terminal. The base station pre-processing rules managing means 35 is adapted to adjust the recommended pre-processing rules according to the current states measured in the terminal current condition measuring means 41. A base station reporting means 43 is also provided between the base station pre-processing rules managing means 35 and the base station communication means 33 and is adapted to report any adjustments made to the pre-processing rules to the terminal. As in the first described embodiment the base station measurement report generating means 37 generates measurement reports according to the adjusted pre-processing rules.
In one embodiment of the invention the base stations provide recommended pre-processing rules that are restricted to the maximum capacity of the base station, i.e. rules advising to perform averaging in the terminal that will generate a maximum number of measurement reports that the base station can handle. The adjustment of the rules in the terminal is then restricted to adjust the rules such that the number of measurement reports is decreased.
In Figure 2a and 2b flow charts of the process steps according to one embodiment of the invention where the adjustments are made in the terminal is shown. In this embodiment the velocity of the terminal is measured in the terminal and used for adjusting the recommended pre-processing rules. Furthermore the bit rate required by the terminal is also used to adjust the rules. The downlink is described in Figure 2a and the uplink in Figure 2b. In this embodiment a measurement signal is continuously sent from the base station to the terminal for the downlink and for the uplink a measurement signal is continuously sent from the terminal to the base station. As mentioned above the measurement signal could instead of being sent continuously be sent together with ordinary data. Starting with Figure 2a:
Dl: A terminal enters the cell of a base station or the terminal is turned on inside the cell.
D3: A communication channel is set up between the terminal and the base station.
D5: During this channel setting up the base station in this embodiment also sends recommended pre-processing rules to the terminal. The pre-processing rules give instructions to the terminal how the measurement reports should be generated regarding for example averaging of the measured signal quality over different time and frequency spans.
D9: A first measuring means in the terminal measures in this embodiment the velocity of the terminal.
DIl: An adjusting means in the terminal receives the velocity measurements and the recommended pre-processing rules and is adapted to adjust the recommended pre-processing rules in dependence of the velocity. The adjustment should in this embodiment also be dependent on the bit rate required by the terminal. The information of required bit rate is provided to the adjusting means from the scheduler in the terminal. For example the recommended pre-processing rules can be adjusted such that the number of measurement reports in the time domain is decreased if the velocity is very low, i.e. the terminal is stationary or close to stationary. It could also be advantageous to decrease the number of measurement reports if the velocity of the terminal is very high since in that case there is no meaning with very detailed measurement reports due to the fast changes on the radio channel and the time delay between the quality measurements and the use of the measurements in the base station. If the required bit rate is low the recommended pre-processing rules could be adjusted such that the number of measurement reports is further decreased. In the case of a low bit rate it could be advantageous to decrease the number of measurement reports by only reporting quality for a fraction of the available bandwidth and/or time intervals instead of changing the frequency and time spans for the averaging.
D 13: The terminal generates measurement reports according to the adjusted pre-processing rules, i.e. for example averaging the quality measurements over the frequency and time spans that are defined in the adjusted pre-processing rules or reporting only for certain frequency and/or time fractions. If multiple transmit antennas are used in this base station the averaging can also be over all or a subset of the antennas or beams of the array antenna.
D 15: The measurement reports are returned to the base station together with information of the adjustments made to the recommended pre-processing rules. The base station need to know which pre-processing rules that have been used in order to be able to read the reports.
The process is then returning to step D9 for measuring a new velocity of the terminal and then the originally sent recommended pre-processing rules are adjusted according to the new velocity and possibly also a new required bit rate. In this embodiment the recommended preprocessing rules are adjusted repeatedly and so often that a new adjustment has been performed each time new measurement reports are sent to the base station. However, generally the adjustment of the pre-processing rules and the transmission of measurement reports do not need to be done with the same rate.
The corresponding process for the uplink is now described:
Ul: A terminal enters the cell of a base station or the terminal is turned on inside the cell.
U3: A communication channel is set up between the terminal and the base station.
U5: During this channel setting up the base station also sends recommended pre-processing rules to the terminal. The pre-processing rules give instructions how the measurement reports should be generated regarding for example averaging of the measured signal quality over different time and frequency spans.
U9: A first measuring means in the terminal measures in this embodiment the velocity of the terminal.
UIl: An adjusting means in the terminal receives the velocity measurements and the recommended pre-processing rules and is adapted to adjust the recommended pre-processing rules in dependence of the velocity and the bit rate as described above for the downlink.
U12: The adjusted pre-processing rules are reported to the base station.
U13: The base station generates measurement reports according to the adjusted pre-processing rules, i.e. averaging the quality measurements over the' frequency and time spans that are defined in the adjusted pre-processing rules. If multiple transmit antennas are used in this terminal the averaging can also be over all or a subset of the antennas or beams of the antennas.
U15: Returning the measurement reports to the terminal.
The process is then started again from U9. The frequency for the adjustments of the recommended pre-processing rules can vary but in this example the rules are adjusted every time measurement reports are sent as described above for the downlink.
If the terminal has adjusted the pre-processing rules such that the quality only is measured by the base station in certain intervals of frequency and/or time the terminal need only to send measurement signals for those intervals that should be measured. This will reduce the power consumption in the terminal and reduce the interference in the system.

Claims

1. A method for handling signal quality measurements in a wireless communication system comprising at least one base station communicating with at least one terminal, characterised by:
- adjusting recommended pre-processing rules for the generation of measurement reports, where said measurement reports comprises signal quality feedback information, said adjusting being based on current conditions experienced in the terminal.
2. A method according to claim 1, comprising
- adjusting said recommended pre-processing rules in the terminal and
- sending from the base station to the terminal said recommended pre-processing rules.
3. A method according to claim 1 or 2, comprising using basic recommended pre-processing rules provided in the terminal if no recommended pre-processing rules are sent from the base station or before any recommended pre-processing rules have been received from the base station.
4. A method according to any one of the preceding claims, comprising reporting to the base station said adjustments made to the pre-processing rules.
5. A method according to any one of the preceding claims, comprising
- measuring in the terminal the signal quality on a measurement signal sent from the base station;
- generating in the terminal measurement reports of the measured signal qualities according to the adjusted pre-processing rules.
6. A method according to any one of the preceding claims, comprising
- forwarding the adjusted pre-processing rules to the base station;
- measuring in the base station the signal quality on a measurement signal sent from the terminal;
- generating in the base station measurement reports of the measured signal qualities according to the adjusted pre-processing rules.
7. A method according to claim 1, comprising
- adjusting said recommended pre-processing rules in the base station and
- sending from the terminal to the base station said recommended pre-processing rules.
8. A method according to claim 1 or 7, comprising using basic recommended pre-processing rules provided in the base station if no recommended pre-processing rules are sent from the terminal or before any recommended pre-processing rules have been received from the terminal.
9. A method according to any one of the claims 1, 7, 8, comprising reporting to the terminal said adjustments made to the pre-processing rules.
10. A method according to any one of the preceding claims, comprising
- adjusting the pre-processing rules such that measurement reports are provided as a function of the measured signal quality for a certain span of frequencies and/or time and/or antennas or beams of an array antenna.
11. A method according to any one of the preceding claims, wherein the current conditions include the velocity of the terminal and/or the time dispersion and/or the spatial correlation of the radio channel between the base station antennas or beams and the terminal and/or the bit rate required by the terminal.
12. A terminal communicating with at least one base station in a wireless communication system, characterised in that it comprises:
- adjusting means (27) adapted to adjust recommended pre-processing rules for the generation of measurement reports, where said measurement reports comprises signal quality feedback information, said adjusting being based on current conditions experienced in the terminal.
13. A terminal according to claim 12, comprising communication means (23) adapted to receive from the base station said recommended pre-processing rules.
14. A terminal according to claim 12 or 13, comprising basic recommended pre-processing rules to be used if no recommended pre-processing rules are sent from the base station or before any recommended pre-processing rules have been received from the base station.
15. A terminal according to any one of the claims 12-14, comprising reporting means (30) connected to the adjusting means (27) and adapted to report to the base station said adjustments made to the pre-processing rules.
16. A terminal according to any one of the claims 12-15, comprising
- a second measuring means (28) adapted to measure the signal quality on a measurement signal sent from the base station;
- a measurement report generating means (29) connected to the second measuring means (28) and to the adjusting means (27) and adapted to generate measurement reports of the measured signal qualities according to the adjusted pre-processing rules.
17. A terminal according to any one of the claims 12-16, wherein the adjusting means (27) is adapted to adjust the pre-processing rules such that measurement reports are provided as a function of the measured signal quality for a certain span of frequencies and/or time and/or antennas or beams of an array antenna.
18. A terminal according to any one of the claims 12-17, wherein the current conditions include the velocity of the terminal and/or the time dispersion of the radio channel between the base station and the terminal and/or the bit rate required by the terminal and/or the spatial correlation of the radio channels between the base station and the terminal.
19. A base station communicating with at least one terminal in a wireless communication system, characterised in that it comprises:
- base station pre-processing rules managing means (35) adapted to send recommended preprocessing rules for the generation of measurement reports to the terminal, where said measurement reports comprises signal quality feedback information, and further adapted to receive adjusted pre-processing rules from the terminal said adjusting being based on current conditions experienced in the terminal; and
- base station measurement report generating means (37) adapted to generate measurement reports according to the adjusted pre-processing rules.
20. A base station communicating with at least one terminal in a wireless communication system, characterised in that it comprises: - base station pre-processing rules managing means (35) adapted to adjust recommended preprocessing rules for the generation of measurement reports, where said measurement reports comprises signal quality feedback information, said adjusting being based on current conditions experienced in the terminal.
21. A base station according to claim 20, comprising communication means (33) adapted to receive from the terminal said recommended pre-processing rules.
22. A base station according to claim 20 or 21, comprising basic recommended pre-processing rules to be used if no recommended pre-processing rules are sent from the terminal or before any recommended pre-processing rules have been received from the terminal.
23. A base station according to any one of the claims 20-22, comprising base station reporting means (43) connected to the base station pre-processing rules managing means (35) and adapted to report to the terminal said adjustments made to the pre-processing rules.
24. A base station according to any one of the claims 20-23, comprising
- a base station measuring means (39) adapted to measure the signal quality on a measurement signal sent from the terminal;
- a base station measurement report generating means (37) connected to the base station measuring means (39) and to the base station pre-processing rules managing means (35) and adapted to generate measurement reports of the measured signal qualities according to the adjusted pre-processing rules.
25. A base station according to any one of the claims 20-24, wherein the base station measurement report generating means (37) is adapted to adjust the pre-processing rules such that measurement reports are provided as a function of the measured signal quality for a certain span of frequencies and/or time and/or antennas or beams of an array antenna.
26. A base station according to any one of the claims 20-25, comprising a terminal current condition measuring means (41) adapted to measure the velocity of the terminal and/or the time dispersion of the radio channel between the base station and the terminal and/or the bit rate required by the terminal and/or the spatial correlation of the radio channels between the base station and the terminal, said measured terminal current conditions are then forwarded to the base station pre-processing rules managing means (35).
PCT/SE2006/050088 2005-04-29 2006-04-27 Method for handling signal quality measurements in a wireless communication system Ceased WO2006118539A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE0501012-9 2005-04-29
SE0501012 2005-04-29

Publications (2)

Publication Number Publication Date
WO2006118539A2 true WO2006118539A2 (en) 2006-11-09
WO2006118539A3 WO2006118539A3 (en) 2006-12-28

Family

ID=37308413

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE2006/050088 Ceased WO2006118539A2 (en) 2005-04-29 2006-04-27 Method for handling signal quality measurements in a wireless communication system

Country Status (1)

Country Link
WO (1) WO2006118539A2 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2461242A (en) * 2007-09-14 2009-12-30 Actix Ltd Mobile phone network management systems
US7941136B2 (en) 2007-09-14 2011-05-10 Actix Limited Mobile phone network optimisation systems
EP3577801A1 (en) * 2017-02-03 2019-12-11 Nec Corporation Communication system with beam quality measurement

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6445917B1 (en) * 1999-05-19 2002-09-03 Telefonaktiebolaget Lm Ericsson (Publ) Mobile station measurements with event-based reporting
TWI225373B (en) * 2002-05-03 2004-12-11 Asustek Comp Inc A flexible scheme for configuring traffic volume measurement reporting criteria
ATE352913T1 (en) * 2002-06-27 2007-02-15 Koninkl Philips Electronics Nv MEASURING CHANNEL CHARACTERISTICS IN A COMMUNICATIONS SYSTEM

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2461242A (en) * 2007-09-14 2009-12-30 Actix Ltd Mobile phone network management systems
GB2461242B (en) * 2007-09-14 2010-06-30 Actix Ltd Mobile phone network management systems
US7941136B2 (en) 2007-09-14 2011-05-10 Actix Limited Mobile phone network optimisation systems
US8032131B2 (en) 2007-09-14 2011-10-04 Actix Limited Mobile phone network management systems
EP3577801A1 (en) * 2017-02-03 2019-12-11 Nec Corporation Communication system with beam quality measurement

Also Published As

Publication number Publication date
WO2006118539A3 (en) 2006-12-28

Similar Documents

Publication Publication Date Title
US10149252B2 (en) Methods and apparatus related to interference management when sharing downlink bandwidth between wide area network usage and peer to peer signaling
KR100355328B1 (en) Radio communication device and method of controlling transmission rate
US8208963B2 (en) Communication method and system
US8909270B2 (en) Avoiding interference in cognitive radio communications
US8219128B2 (en) Network-centric link adaptation for coordinated multipoint downlink transmission
CN107070622B (en) Terminal device, communication method, and integrated circuit
US8295869B2 (en) Method and apparatus for improving transmission efficiency in a mobile radio communications system
US9226301B2 (en) System and method to shorten the time taken to improve inter-cell interference mitigation performance using adaptive fractional frequency reuse
US8271042B2 (en) Self-calibrating multi-antenna wireless communication system
CN101507142A (en) Method for transmitting data in a mobile system and radio station thereof
CA2290406C (en) Base station (apparatus and method) with directivity and transmission power control
WO2006118539A2 (en) Method for handling signal quality measurements in a wireless communication system
US20160204919A1 (en) Method and Controlling Node for Controlling Radio Communication in a Cellular Network
JP4564430B2 (en) COMMUNICATION DEVICE, COMMUNICATION METHOD, RADIO COMMUNICATION SYSTEM, AND RADIO COMMUNICATION METHOD
US20210211936A1 (en) Terminal device, wireless communication system, and wireless transmission method
CN107205240B (en) Method and system for determining stability of wireless signal
KR20090103666A (en) Method for avoiding inter-cell interference in a multi-cell environment
WO2025159911A1 (en) Channel state information reference signal (csi-rs) resource mapping scheme management for massive mimo systems
CN102594428B (en) Signal-to-noise ratio feedback method and device
WO2024163283A1 (en) Multiple user multiple input multiple output (mu-mimo) transmission precoder management using neighbor lists
WO2024173110A1 (en) Multiple user multiple input multiple output (mu-mimo) transmission precoder management using user equipment (ue) grouping based on location

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application
NENP Non-entry into the national phase

Ref country code: DE

NENP Non-entry into the national phase

Ref country code: RU

122 Ep: pct application non-entry in european phase

Ref document number: 06733458

Country of ref document: EP

Kind code of ref document: A2