JP4494250B2 - Receiver - Google Patents

Description

  The present invention relates to a receiving device used for an RF receiving device of an indoor base station such as a mobile phone.

  When a radio wave transmitted from a mobile phone or the like is received by a base station, a multipath environment in which a plurality of reaching waves due to reflection, transmission, diffraction, etc. exist in addition to direct waves. Multipath is a “delayed wave” that arrives slightly later than the direct wave.

In the W-CDMA system, as shown in FIG. 1, received signals (r ₁ , r ₂ , r ₃ ) scattered and arrived by multipath fading within one symbol are separated using a plurality of correlation receivers, RAKE reception, which is a method of combining scattered signals and increasing signal power for reception, is employed.

On the other hand, in the indoor multipath environment, the arrival direction of radio waves is not biased compared to the outdoors and is widely distributed. Furthermore, the polarized waves change due to the reflection and diffraction of radio waves, resulting in an electromagnetic field distribution in which various polarized waves exist. In such a situation, polarization diversity is an effective method.
The applicant could not find prior art documents related to the present invention as a technique for converting polarization diversity into RAKE reception. Therefore, prior art document information is not disclosed.

  However, the background art described above has the following problems.

  Polarization diversity is an effective technique in indoor multipath environments where various types of polarization exist, but it is necessary to introduce polarization diversity without changing the operation system, and polarization polarization is converted to RAKE reception. There is a problem that it is difficult to realize the apparatus.

  Accordingly, an object of the present invention is to provide a receiving apparatus that converts predetermined diversity into time diversity without changing the operation system in indoor cellular phone communication employing the W-CDMA system.

The receiving apparatus,
The plurality of branches from a plurality of antennas, and a delay processing unit that generates a delayed signal by Rukoto give a relative delay time,
A power combining unit that combines power of the delayed signal generated by the delay processing unit ,
The plurality of antennas include a plurality of electric field antennas operated by electric field components of radio waves and a plurality of magnetic field antennas operated by magnetic field components of radio waves,
The delay processing unit gives a delay time shifted for each of a plurality of branches from the plurality of electric field antennas and the plurality of magnetic field antennas.

  By configuring in this way, a plurality of branches having a small correlation can be converted to time diversity, and RAKE combining can be performed in the base station apparatus.

  According to the embodiment of the present invention, it is possible to realize a receiving apparatus that converts predetermined diversity into time diversity without changing the operation system in indoor cellular phone communication employing the W-CDMA system.

Next, embodiments of the present invention will be described with reference to the drawings.
In all the drawings for explaining the embodiments, the same reference numerals are used for those having the same function, and repeated explanation is omitted.

  A receiving apparatus according to an embodiment of the present invention generates a delayed signal by giving a relative delay time to a plurality of branches having small correlations received from a plurality of antennas, and these delayed signals are generated at an RF stage. Combine power.

  As an example, a case where polarization diversity using an electric field antenna that receives an electric field component of a radio wave and a magnetic field antenna that receives a magnetic field component of a radio wave will be described with reference to FIG.

The delay synthesizer 100 as a receiving device is intended for a receiving antenna of an indoor base station, and includes electric field antennas 120 ₁ , 120 ₂ and 120 ₃ , magnetic field antennas 120 ₄ , 120 ₅ and 120 ₆ , and electric field antennas 120 ₂ and 120. ₃ , delay filters 106 ₂ and 106 ₃ respectively connected to the magnetic field antennas 120, delay filters 106 ₄ , 106 ₅ and 106 ₆ respectively connected to the magnetic field antennas 120 ₄ , 120 ₅ and 120 ₆ , the electric field antenna 120 ₁ , and the delay filter 106 ₂ , 106 ₃ , 106 ₄ , 106 ₅ and 106 _6, and a power combiner 104 connected to the power combiner 104. The delay filters 106 ₂ , 106 ₃ , 106 ₄ , 106 _5, and 106 ₆ constitute the delay processing unit 102.

The electric field antennas 120 ₁ , 120 _2, and 120 ₃ are operated by the electric field component of radio waves, and receive the X component (r ₁ ), Y component (r ₂ ), and Z component (r ₃ ) of the electric field, respectively. The electric field antennas 120 ₁ , 120 _2, and 120 ₃ input the branches to the power combining unit 104, the delay filter 106 _2, and the delay filter 106 ₃ , respectively.

The magnetic field antennas 120 ₄ , 120 _5, and 120 ₆ are operated by the magnetic field components of radio waves, and receive the X component (r ₄ ), Y component (r ₅ ), and Z component (r ₆ ) of the magnetic field, respectively. The electric field antennas 120 ₄ , 120 _5, and 120 ₆ input the branches to the delay filter 106 ₄ , the delay filter 106 _5, and the delay filter 106 ₆ , respectively.

Delay filter 106 _2, an electric field antenna 120 ₂ predetermined time Y components of the received electric field signal by, for example, by Δt delay, is input to the power combiner 104. The delay filter 106 ₃ delays the Z component of the electric field signal received by the electric field antenna 120 ₃ by a predetermined time, for example, 2Δt, and inputs the delayed signal to the power combining unit 104.

Delay filters 106 _4, the magnetic field antenna 120 ₄ time given the X component of the received magnetic field signal by, for example, by 3Δt delayed input to the power combiner 104. Delay filter 106 _5, the magnetic field antenna 120 ₅ predetermined time Y components of the received magnetic field signal by, for example, by 4Δt delayed input to the power combiner 104. Delay filter 106 _6, the magnetic field antenna 120 ₆ time given the Z component of the received magnetic field signal by, for example, by 5Δt delayed input to the power combiner 104. That is, the delay processing unit 102 gives a relative delay time to the branches from the input electric field antennas 120 ₂ and 120 ₃ and the branches from the magnetic field antennas 120 ₄ , 120 ₅ and 120 ₆ .

  The power combining unit 104 combines power based on the delay profile of the input delay signal. For example, the branch received from each antenna is input to the power combining unit 104 with a delay of Δt. These delay signals are combined in power.

  The power-combined signal is RAKE-received by a base station apparatus in a layer above the MOF (Multi-drop Optical Feeder). For example, in the base station apparatus, a finger is assigned to the corresponding signal position of the power-combined signal, and the received signal obtained by the assigned finger is synthesized in the maximum ratio.

  RAKE reception is path diversity in which the path itself has a delay. In the present embodiment, polarization diversity is converted to time diversity. That is, delays shifted for each branch are added to the 6-branch waves received by the antennas for different polarizations, and the power is synthesized. By doing so, RAKE reception (path diversity combining) can be performed in the base station apparatus.

  The radio wave environment differs between outdoors and indoors. Therefore, in the receiving apparatus 100 according to the present embodiment, a magnetic field component is used.

  The radio wave environment around the outdoor base station will be described.

  Generally, an outdoor base station is installed at a higher position than other buildings and is further sectorized. As a result, the outdoor base station viewed from the mobile station side exists at a substantially fixed angle. A radio wave emitted from a mobile station is affected by movement of the mobile station itself, reflection by a building, and scattering / shielding by a car / building, etc., and fading occurs. However, since the position of the base station viewed from the mobile station is almost fixed in the outdoor environment, the arrival direction of radio waves is biased.

  The radio wave is propagated by alternating electric and magnetic fields, and the electric field strength [V / m] divided by 120π and rotated is the magnetic field strength [A / m].

  When the arrival directions of radio waves are biased as in the case of the outdoor base station, the correlation between the electric field strength and the magnetic field strength is high because the magnetic field strength of each element wave arrives in a biased arrival direction.

  On the other hand, in the indoor environment, the distance between the mobile station and the indoor base station is short, it is a closed space, it is a multiwave environment, and since it is not sectorized, the direction of arrival of radio waves is widely distributed. Yes. As a result, when considering each elementary wave, the relationship between the electric field and the magnetic field follows Gauss's law, but the electric field strength and magnetic field strength obtained by adding the elementary waves have low correlation and are independent.

  From the above, it is effective to employ each polarization of the electric field component and each polarization of the magnetic field component as the diversity branch in the indoor environment. Further, each component can be received by an electric field type antenna or a magnetic field type antenna and taken in as electric power [dBm].

  The magnetic field strength [A / m] is calculated by dividing the electric field strength [V / m] by 120π. However, there is no unreasonable gain due to (1) the fundamental wave and (2) the fact that the units are different and cannot be compared. For this reason, it can be employed as a diversity branch. The problem of improper gain is due to the gain of the antenna.

  Next, the delay processing unit 102 in the receiving apparatus 100 according to the present embodiment will be described in detail with reference to FIG.

  In an indoor environment, since the propagation distance is short, neither time nor delay necessary for path separation for RAKE synthesis occurs. Even when a delay occurs, effective path diversity cannot be performed because the signal is attenuated to a considerably low level. Also, in order to RAKE combine received signals with each antenna, a receiving device with each antenna is required and cannot be configured with a single receiving device.

  Therefore, in the present embodiment, a delay wave is inserted in each branch, and by changing the delay time of these delay filters, received waves having different delay times from, for example, 0 ns to 1300 ns are realized. In order to make the output level of each branch the same, an amplifier and an attenuator are inserted in each branch to adjust the level.

  In the present embodiment, a circuit configuration for delaying 6-branch waves as described above will be described. The waves input to each branch are received waves having different polarizations as described above. The finger time resolution in RAKE reception depends on the chip rate. For example, when the chip rate is 3.84 MHz, the time resolution Δt = 1 / 3.84 MHz = 260 ns. Therefore, in this embodiment, a case where 260 ns is used as Δt will be described.

The delay processing unit 102 includes amplifiers 108 _{1 to} 108 ₆ , isolators 110 _{2 to} 110 ₆ connected to the amplifiers 108 _{2 to} 108 _6, and delay filters connected to the isolators 110 _{2 to} 110 ₆ , respectively. 106 ₂ to 106 _6, a delay filter ₁₀₆ 2 to 106 ₆ and the variable attenuator ₁₁₂ 2-112 ₆ connected respectively, a variable attenuator 112 ₁ connected to the amplifier 108 _1, the variable attenuator ₁₁₂ 1-112 ₆ and a power combining unit 104 connected to the power supply unit 104.

Received signal electric field antenna ₁₂₀ 1-120 ₃ and the magnetic field antenna ₁₂₀ 4-120 ₆ is amplified by an amplifier ₁₀₈ 1 to 108 _6, a signal amplified by the amplifier 108 ₁ is input to the variable attenuator 112 _1, amplifiers 108 signal amplified by _{2-108 6} isolator - via the motor ₁₁₀ 2-110 ₆ is input to the delay filter ₁₀₆ 2-106 _6.

Delay filter 106 _2, time input signal having a predetermined, for example, by 260ns delay and input to the variable attenuator 112 _2. Delay filter 106 _3, time input signal having a predetermined, for example, by 520ns delay and input to the variable attenuator 112 _3. Delay filters 106 _4, time input signal having a predetermined, for example, by 780ns delay and input to the variable attenuator 112 _4. Delay filter 106 _5, time input signal having a predetermined, for example, by 1040ns delay is input to the variable attenuator 112 _5. Delay filter 106 _6, time input signal having a predetermined, for example, by 1300ns delay is input to the variable attenuator 112 _6. Thus, the delay filters 106 _{2 to} 106 ₆ provide relative delay times for the branches from the input electric field antennas 120 ₂ and 120 ₃ and the branches from the magnetic field antennas 120 ₄ , 120 ₅ and 120 _6. .

Variable attenuator ₁₁₂ 1-112 ₅ adjusts the level of the input signal, and inputs to the power combiner 104.

Power combiner 104, a variable attenuator ₁₁₂ 1-112 _5, to power combining the signals input respectively by Δt delay.

In this embodiment, the received wave in the delay filters ₁₀₆ 2-106 ₆ has been described the case of inserting an amplifier ₁₀₈ 1 to 108 ₆ for damping, the amplifier is not required as long as the attenuation is small, passive You may make it comprise only an element.

  Since the time resolution of RAKE reception in the W-CDMA system is a chip rate level and is currently about 260 ns, it can be recognized as a delayed wave in RAKE reception by setting the delay of one branch to 260 ns or more. it can.

  In the above-described embodiments, the case where polarization diversity is converted to time diversity has been described. However, the same effect can be obtained even if various diversity branches such as space diversity are converted to time diversity.

  For example, when converting space diversity into time diversity, a plurality of antennas are arranged at spatially separated positions, and antenna output with instantaneous level fluctuation is converted into time diversity, and power is combined.

  In the above-described embodiment, the case of delaying waves of 6 branches has been described. However, any wave of 2 branches or more can be applied.

  According to the embodiment of the present invention, polarization diversity can be realized without changing the indoor base station apparatus system. Further, power consumption can be improved, which contributes to low power consumption of the mobile phone and an increase in the number of users that can be accommodated.

  The receiving apparatus according to the present invention can be applied to an RF receiving unit apparatus of an indoor base station such as a mobile phone.

It is explanatory drawing which shows RAKE reception. It is a block diagram which shows the receiver concerning one Example of this invention. It is a block diagram which shows the receiver concerning one Example of this invention.

Explanation of symbols

100 receiver 102 delay processing unit 104 power combining unit 106 ₂ , 106 ₃ , 106 ₄ , 106 ₅ , 106 ₆ delay filter 108 ₁ , 108 ₂ , 108 ₃ , 108 ₄ , 108 ₅ , 108 ₆ amplifier 110 ₂ , 110 ₃ , _{110 4,} 110 5, 110 ₆ isolator - motor _{112 1,} 112 _{2, 112} 3, 112 _4, 112 5, 112 ₆ variable attenuator _{120 1,} 120 2, 120 ₃ field antenna _{120 4,} 120 5, 120 ₆ Magnetic field antenna

Claims (4)

The plurality of branches from a plurality of antennas, and a delay processing unit that generates a delayed signal by Rukoto give a relative delay time,
A power combining unit that combines the delay signal generated by the delay processing unit ,
The plurality of antennas includes a plurality of electric field antennas operated by electric field components of radio waves and a plurality of magnetic field antennas operated by magnetic field components of radio waves,
The delay processing unit, the plurality of receiving devices, characterized in Rukoto give a plurality of delay time offset for each branch from the electric field antenna and said plurality of magnetic field antenna. The receiving device according to claim 1,
The delay processing unit includes an X component, a Y component, and a Z component of an electric field received from the plurality of electric field antennas, and an X component, a Y component, and a Z component of a magnetic field received from the plurality of magnetic field antennas. A receiving apparatus characterized by giving a delayed delay time. The receiving apparatus according to claim 1 or 2 ,
The receiving apparatus according to claim 1, wherein the delay processing unit gives a relative time delay to the plurality of branches according to a time resolution of a finger in RAKE reception. The receiving apparatus according to any one of claims 1 to 3 ,
The receiving apparatus, wherein the delay processing unit gives a relative delay time to a plurality of branches from a plurality of antennas arranged at spatially separated positions.

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