Classifications

• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03G—CONTROL OF AMPLIFICATION
  • H03G3/00—Gain control in amplifiers or frequency changers
  • H03G3/20—Automatic control
  • H03G3/30—Automatic control in amplifiers having semiconductor devices
  • H03G3/3052—Automatic control in amplifiers having semiconductor devices in bandpass amplifiers (H.F. or I.F.) or in frequency-changers used in a (super)heterodyne receiver
  • H03G3/3068—Circuits generating control signals for both R.F. and I.F. stages
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
  • H04B1/06—Receivers
  • H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
  • H04B1/1027—Means associated with receiver for limiting or suppressing noise or interference assessing signal quality or detecting noise/interference for the received signal

Definitions

• the present invention relates to an adaptive radio .re ⁇ ceiver apparatus and, more specifically, a radio receiver suitable for use in a base station or a mobile telephone in a telecommunication system or a telecommunication system having radio in the local loop.
• the radio receiver is c ⁇ n- trollable for optimising operating parameters of the ampli ⁇ fication circuits included in the receiver, e.g. gain, noise figure, blocking and IP3 intercept levels, in dependence of the traffic situation in which the receiver is located.
• the radio receiver in accordance with the invention utilises controllable amplifiers and adaptive control logic for con ⁇ trolling the operating parameters.
• the receiver In the base stations and mobile stations or other radio terminals of today the receiver is designed as a compromise mainly between intercept/blocking level and noise figure. This results in a quite modest performance in both respects. Thus, the problem is that a general receiver is not suitable for the various traffic situations encountered in a telecom- munication system.
• a solution is to make one type of base station for areas with intensive traffic, typically cities, having high intercept level and poor noise figure, and another type of base station for areas with low traffic intensity, such as rural areas, having low noise figure and low intercept level.
• the traffic situation is not stable, but the requirements may vary with time.
• the present invention proposes to solve the problem stated above by providing an adaptive radio receiver appara- tus which may be optimised with respect to one or more of a plurality of operating parameters. This means that the same receiver may be used in all environments and having the best performance possible and the power consumption may also be reduced in accordance with the traffic environment.
• the present invention provides an adaptive radio re ⁇ ceiver apparatus connected to an antenna, a duplex filter, a local oscillator and a mixer as is conventional in the art.
• the receiver appara ⁇ tus comprises at least one controllable amplifier stage which is under control from a control unit for varying the operating parameters of the amplifier stage in dependence of the environment .
• the amplifier * stage preferably includes a controllable low noise amplifier and a variable attenuation attenuator.
• the receiver apparatus has the capacity of con ⁇ trolling the operating parameters such as the blocking level, the intercept level, the sensitivity, the noise figure, the power consumption and the gain.
• the control unit comprises control logic for forming combinations of the ope ⁇ rating parameters, each combination corresponding to a spe ⁇ cific traffic situation.
• Figure 1 is a circuit diagram of a first embodiment of the invention having a frequency independent splitter
• Figure 2 is a circuit diagram of another embodiment of the invention in which the signal is split into different frequency bands
• Figure 3 is a circuit diagram of an alternative em- bodiment of a controllable amplifier in accordance with the invention.
• receivers of e.g. base stations of mobile telecommunication systems have different require ⁇ ments in dependence of the environment in which they are to be used.
• Figure 1 describes how such an adaptive radio receiver is realized in accordance with one embodiment of the inven ⁇ tion.
• the receiver is connected to an antenna through a duplex filter DPX as is conventional.
• the receiver comprises low noise amplifiers GI and G2 and a splitter SP1, splitting the signal such that a plurality of radio channels may be received at the same time.
• the signal i ⁇ split by the splitter and then mixed into tuned receivers of which only the first mixer MIX11 is shown.
• the signal is divided by a filter bank Fll, F21, F31, in which each filter corresponds to one radio channel .
• the receiver apparatus is optimised by varying the attenuation of variable attenuators Al, A2, A3, A13 and by varying the bias of the amplifiers
• a control unit controls the bias of the various components .
• the attenuators Al, A2, A3, A4 and A13 receive the bias voltages Ul, U4, U7, U10 and U16, respectively.
• the amplifier units GI, G2 and G12 receive the bias voltages U3 , U6, and Ull, respectively, as well as the bias currents II, 12 and 112, respectively. Since the input impedances of the amplifiers GI, G2 are affected by the bias there are variable matching networks Ml, M2 in front of the amplifiers Gl, G2.
• the matching net ⁇ works may be implemented e.g. by varactors or PIN diodes and are controlled by the input voltages U2 and U5.
• variable attenuators Al and A2 have been introduced in front of the amplifiers.
• the attenuators may consist of PIN diodes and may also contain capacitive and reactive components to provide broad band characteristics and optimal work load. These may also attenuate the input signal in those cases when a current lean function mode is used, as Gl and G2 may sustain lower input power without being overloaded.
• the output level of G2 is measured by the directional coupler with detector DC2 and the result of the measurement is used to adjust the bias of Gl and G2 (and Ml, M2) as well as the attenuation of Al, A2.
• the output signal of G2 will be relatively small and in that case the mixer MIX11 is not required to have a large LO power. Thereby, the gain of the buffer stage G12 may be lowered by decreasing the bias Ull, 112. In order to prevent overloading of MIX11 the signal may be attenuated in A13.
• phase shifter PS In case the receiver is used together with a phase con- trolled antenna the phase shift is required to be identical in the various receivers. For this reason, a signal from an oscillator OSC is injected through the directional coupler DCI and the signal after the amplifiers is measured in the comparator C0MP1.
• the attenuator A4 may be used to set the right level of COMP1 such that the phase is measured cor ⁇ rectly, and the result of the phase measurement S5 is used to control the variable phase shifter PS using the voltage U8 such that the correct phase orientation is maintained.
• the table below shows four examples of various setting yielding various performance of the receiver apparatus.
• the values shown refers to the circuit diagram of Figure 1, the gain being the total gain of the apparatus.
• the four cases are well adapted to the traffic cases mentioned above.
• many intermediate cases and combinations are possible in order to optimise for different conditions.
• DCI Downlink Control
• DC2 Downlink Control
• DC3 a portion of the power received is coupled to a detector measuring the strength of the strongest incoming signal. This information is supplied to a control unit, herein referenced as Multicoupler Controller.
• a temperature sensor may be included to optimise the bias of the transistors of the amplifiers as a function of the temperature.
• the signal S7 from the temperature sensor may be included to optimise the bias of the transistors of the amplifiers as a function of the temperature.
• SUBSTITUTE SHEET is also supplied to the controlled unit .
• the temperature sensor is preferably located near the various components.
• the entire apparatus is controlled by the Multicoupler Controller through the various voltages and currents to the attenuators and amplifiers.
• the Multicoupler Controller also receives input data from a Base Site Controller BSC, the de ⁇ tectors DCI, DC12, DC13, and from the temperature sensor.
• the control unit may be a single chip processor.
• the power consumption of the amplifier G12 may be optimised using the control unit.
• the amplifier G12 associated with the local oscillator LOll and the mixer MIX11 is used to control the LO power to the mixer and receives an input voltage Ull and input current 112 controlled by the control unit.
• a high intercept level requires a high local oscillator power, contrary to other operating modes. This fact is used to optimize the LO amplifier in the same way as the other amplifiers of the receiver.
• FIG. 2 shows another embodiment of the invention in which a filter bank comprising filters Fll, F21, F31 are set to pass certain frequencies to respective amplifier channels.
• the filters are set such that the two branches ⁇ from the splitter SP2 pass alternate channels. In this way, the pass frequencies of the filters of one branch may overlap filters of the other branch without losses since the overlap does not occur in the same physical line. Thus, con ⁇ tinuous channel coverage is obtained.
• the separate channels enable an individual setting or matching of the amplifiers of each channel.
• Each amplifier channel comprises similar components to the embodiment of Figure 1, for which reason they are not described again in great detail.
• an alternative embodiment of the first amplifier Gl in Figures 1 and 2 is replaced by a number, e.g. two or four, of amplifier units connected in parallel.
• the amplifiers Gl, G2, G3, G4 may be switched on or off by a switch network comprising eight switches SW1 to SW8.
• the impedance values are calculated to ensure that the input impedance and output impedance of the amplifier circuit is maintained at the correct value, typically 50 ⁇ , irrespective of the number of activated amplifier units, as is well known in the art.
• the switches SW1-SW4 and SW9-SW10 together with the transmission lines TRL1-TRL7 are used to maintain match to 50 ohm inde ⁇ pendently of the number of amplifiers that are connected.
• the input impedance of the amplifiers G1-G4, which are 50 ohm in this example, are transformed to 30 ohm by the transmission line TRL.
• SW1 When one amplifier is disconnected (e.g. Gl) , SW1 connects TRLl to ground. This ground connection will trans ⁇ form to an open circuit at the connecting point A, and thus will have no effect on matching.
• the impedance seen at point A when looking into the amplifiers G1-G2 will depend on the number of amplifiers connected in parallel:
• the switches SW9-SW10 and TRL5-TRL7 are used to trans ⁇ form these impedances to 50 ohm.
• the switches will be in the following position depending on the number of amplifiers connected: Numbers of amplifiers SW9 SW10
• TRL6 and TRL5 are connected in parallel with TRL7, or connected to ground depending on the position of switches SW9 and SW10. When they are connected to ground, the short- circuit will be transformed to an open circuit at the other end of the transmission line. The open circuit line will not have any impact on the rest- of the circuit. When they are connected in parallel, the characteristic impedance of the resulting line is changed in the same way as when two re ⁇ sistors are connected in parallel. These different characte- ristic impedances are used to obtain matching to 50 ohm.

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• Amplifiers (AREA)
• Circuits Of Receivers In General (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20402376

Family Applications (1)

Country Status (5)

Cited By (18)

Citations (8)

• 1996
  • 1996-04-29 SE SE9601620A patent/SE9601620L/sv not_active Application Discontinuation
• 1997
  • 1997-03-24 JP JP9538783A patent/JP2000509231A/ja active Pending
  • 1997-03-24 AU AU23140/97A patent/AU2314097A/en not_active Abandoned
  • 1997-03-24 WO PCT/SE1997/000504 patent/WO1997041643A1/en not_active Application Discontinuation
  • 1997-03-24 EP EP97915810A patent/EP0956649A1/en not_active Withdrawn

Patent Citations (8)

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