Classifications

• • 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

Definitions

• the present invention relates to an adaptive air inter ⁇ face suitable for use in a cellular telecommunication sys ⁇ tem.
• the air interface is the hardware and software device providing means for communicating over the free space with a device containing exactly the same air interface.
• An air in ⁇ terface contains various kinds of information elements to make this possible such as framing data, synchronization data, information data and error control data.
• the present invention solves the above-mentioned problem by providing an air interface that is adapted to various re ⁇ quirements in dependence of the current operating conditions and needs.
• the adaptive air interface in accordance with the invention includes means for collecting parameter require ⁇ ments, means for relating the parameter requirements to an input space, means for transforming the input space to an output space, the output space defining the operating para- meters of the air interface.
• Figure 1 is a block diagram of the transformation of the input space to the output space in accordance with the in ⁇ vention
• Figure 2 is a block diagram of the fuzzy logic control in accordance with the invention
• FIGS 3A to F are diagrams of the input variable membership functions
• FIGS 4A to F are diagrams of the output variable membership functions.
• the air interface in accordance with the present in ⁇ vention is described with respect to a mobile telecommuni- cation system below, but is equally applicable to other air interfaces as is appreciated by a person skilled in the art.
• the adaptive air interface contains a number of parameters and schemes that are controlled adaptively. Some of the pro- porties of the adaptive air interface are
• the air interface according to the invention enables adaptivity according to situations and scenarios at hand. A number of possibilities arises namely with the following adaptable parameters in what is called the output space
• the decisions behind the parameters are based on mea ⁇ surements, user needs, operator considerations and given re ⁇ sources using an optimizing algorithm. These parameter re ⁇ quirements are collected by the interface.
• the requirements are related to the input data or the input space consisting of the following parameters
• Figure 1 is shown a block diagram of the transfor ⁇ mation of the input space to the output space.
• the input space is processed by a logic control box including rules for the transformation.
• a finite state machine has a finite number of states of the input variables which are transformed by logic rules to output variables. Below is an example of logic rules in a finite state machine.
• fuzzy logic controller operates on a number of membership functions ⁇ . For each variable a number of membership functions are defined.
• the membership func ⁇ tions may assume various values ranging from zero to one and not just the discrete numbers zero and one.
• each input variable has a set of three membership functions taking on different values for a specific value on the x axis .
• the fuzzy logic controller contains rules for trans ⁇ forming the input membership functions to output membership functions.
• An example of output membership functions is illustrated in Figures 4A to F.
• the fuzzy logic controller also includes rules for "defuzzufication" which gives a crisp value on the x axis for the set of mem ⁇ bership function values.
• fuzzy logic controller also called' fuzzy rule base
• fuzzy rule base The logic rules of the fuzzy logic controller, also called' fuzzy rule base, are determined by detailed sec ⁇ gation of the particular problem at hand. There are commer- cially available computer-aided methods for defining, tuning and optimising the fuzzy rule base.
• Input xc implies x ir where x i ⁇ xc ⁇ x i +l.
• the output variables can assume the following values :
• Optimization of output variables, according to selected cost functions, is performed in order to e.g. maximize quan ⁇ tities like capacity and throughput, minimize power from the base station and the mobile station. Optimization is performed on the following variables:
• the cost function CF is based upon the following rule performance x quality

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

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• 1996
  • 1996-04-29 SE SE9601617A patent/SE515509C2/sv not_active IP Right Cessation
• 1997
  • 1997-03-24 AU AU21876/97A patent/AU2187697A/en not_active Abandoned
  • 1997-03-24 WO PCT/SE1997/000498 patent/WO1997041675A1/en not_active Ceased
  • 1997-03-24 EP EP97914742A patent/EP0898830A1/de not_active Withdrawn

Non-Patent Citations (1)

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