ANTENNA ARRAY SYSTEM

• US 20090252205A1
• Filed: 12/19/2008
• Published: 10/08/2009
• Est. Priority Date: 07/17/2006
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Kathrein-Werke KG. (Kathrein SE)
• Inventors: Korte, Werner, Rheinfelder, Clemens, Korte-Gericke, Ingeborg Sigrid Ilse-Dore
• Granted Patent: US 8,711,903 B2
• Time in Patent Office: Days
• US Class Current: 375/219
• CPC Class Codes: H04B 1/18 Input circuits, e.g. for coupling to an antenna or a transmission line coupling networks between antennas or lines and receivers independent of the nature of the receiver H03H
• CPC Class Codes: H04B 1/40 Circuits
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

Antenna system connectable to a base station, the antenna system comprising a digital radio unit connectable to at least one antenna element, wherein the digital radio unit comprises: at least one micro radio for receiving/sending digital radio signals having a digital down-converter/a digital up-converter and a digital signal converter. The at least one micro radio converts the digital radio signals to analogue RF (radio frequency) signals and vice versa. The at least one micro radio has at least one hub for processing digital radio signals and control signals and for routing said digital radio signals and control signals via at least one serial link and at least one interface. The at least one serial link is provided between the at least one hub and the at least one micro radio.

Claims

1. An antenna system connectable to a base station, the antenna system comprising a digital radio unit connectable to at least one antenna element, wherein the digital radio unit comprises:

at least one digital micro radio for receiving/sending digital radio signals having a digital down-converter/a digital up-converter and a digital signal converter;

whereby the at least one micro radio converts the digital radio signals to analogue RF (radio frequency) signals and vice versa;

at least one hub for processing digital radio signals and control signals and for routing said digital radio signals and control signals via at least one digital link and at least one interface, the at least one digital link being provided between the at least one hub and the at least one micro radio.

2. The antenna system according to claim 1, wherein the at least one micro radio is operable in FDD mode and comprises:

a FDD filter unit connected at a receive output to an input of a low noise analogue-to-digital converter and further connected at a transmit input to an output of a power digital-to-analogue converter;

a digital transceiver connected at an output for signal to an input of the power digital-to-analogue converter and further connected at an input for signal to an output of the analogue-to-digital converter, the digital transceiver having a receive section and a transmit section, the digital up-converter being part of the transmit section and the digital down-converter being part of the receive section;

a receive clock oscillator unit for providing a sampling clock for the analogue-to-digital converter and for the receive section of the digital transceiver and for further providing a sub-sampling pulse for said receive section;

a transmit clock oscillator unit for providing a sampling clock for the power digital-to-analogue converter and for the transmit section of the digital transceiver.

3. The antenna system according to claim 2, wherein the analogue-to-digital converter comprises a low noise amplifier followed by a continuous-time sigma-delta band-pass modulator converting the RF signal at the input directly into a digital single/1.5 bit band-pass output signal.

4. The antenna system according to claim 2, wherein the power digital-to-analogue converter utilizes 2 or 3 voltage levels to convert a digital single/1.5 bit band-pass input signal directly into an analogue RF output signal.

5. The antenna system according to claim 1, wherein the at least one micro radio is operable in TDD mode and comprises:

a TDD filter unit followed by a TDD switch connected at a receive output to an input of a analogue-to-digital converter and further connected at a transmit input to an output of a power digital-to-analogue converter;

a digital transceiver connected at an output for signal to an input of the power digital-to-analogue converter and further connected at an input for signal to an output of the analogue-to-digital converter, the digital transceiver having a receive section and a transmit section, the digital up-converter being part of the transmit section and the digital down-converter being part of the receive section;

at least one clock oscillator unit for providing a sampling clock for the analogue-to-digital converter, the power digital-to-analogue converter, and the digital transceiver and for further providing a sub-sampling pulse for the receive section of the digital transceiver and a time control signal for the TDD switch.

6. The antenna system according to claim 5, wherein the analogue-to-digital converter comprises a low noise amplifier followed by a continuous-time sigma-delta band-pass modulator converting the RF signal at the input directly into a digital single/1.5 bit band-pass output signal.

7. The antenna system according to claim 2, wherein the power digital-to-analogue converter utilizes 2 or 3 voltage levels to convert a digital single/1.5 bit band-pass input signal directly into an analogue RF output signal.

8. The antenna system according to claim 1, wherein the digital up-converter utilizes a unit performing quadrature modulation by 2:

1 multiplexing and cyclic negation in combination with a time-discrete sigma-delta band-pass modulator or two time-discrete sigma-delta low-pass modulators to output a digital single/1.5 bit band-pass signal being directly up-converted from a digital base-band signal; and

wherein the digital down-converter utilizes a unit performing quadrature demodulation by 1;

2 de-multiplexing and cyclic negation followed by two systolic FIR decimators to down-convert the digital single/1.5 bit band-pass input signal directly into a digital base-band signal.

9. The antenna system according to claim 8, wherein the time-discrete sigma-delta band-pass modulator is realized as a systolic array.

10. The antenna system according to claim 8, wherein the two time-discrete sigma-delta low-pass modulators are realized as systolic arrays.

11. The antenna system according to claim 1, wherein digital base-band signals are processed by the at least one hub within time and frequency domain.

12. The antenna system according to claim 1, wherein at least one micro controller and at least one control bus are embedded in the at least one hub;

whereby processing and routing of digital base-band signals and control signals by the at least one hub is controlled and monitored by said micro controller.

13. The antenna system according to claim 1, wherein the at least one hub comprises at least one Frequency Multiplexer &

De-Multiplexer unit comprising;

at least one digital quadrature modulator for combining a plurality of digital base-band signals to a digital multi-carrier signal;

at least one digital quadrature demodulator for splitting a digital multi-carrier signal into a plurality of digital base-band signals.

14. The antenna system according to claim 1, wherein the at least one hub comprises at least one Sampling Rate Converter unit for synchronizing the sampling frequency of digital multi-carrier signals within the at least one Frequency Multiplexer &

De-Multiplexer with the sampling frequencies of digital band-pass signals and within the at least one micro radio utilizing a variable over-sampling ratio.

15. The antenna system according to claim 1, wherein the at least one hub comprises at least one Amplitude &

Phase Aligner unit comprising at least one complex digital multiplier stage for adjusting amplitude and phase of digital band-pass signals and within the at least one micro radio under software control.

16. The antenna system according to claim 1, wherein the at least one hub comprises at least one Time Multiplexer &

De-Multiplexer and Hub unit for handling the routing of incoming and outgoing data streams via at least one SerDes interface unit under software control.

17. The antenna system according to claim 1, wherein the at least one hub comprises at least one Master Clock Oscillator unit being synchronized to the time reference of the Digital Radio Server by the at least one Master SerDes interface unit for providing clock signals for all units of the at least one hub and for synchronizing the clock units of the at least one micro radio.

18. The antenna system according to claim 1, wherein the at least one serial link between the at least one hub and the at least one micro radio is a digital bi-directionally serial link transporting digital base-band signals and adjacent control information as packet data in a partially filled frame format, wherein an adjustment of frame length and format and further the number of samples per frame is software controllable.

19. The antenna system according to claim 2, wherein the at least one micro radio further comprises an additional power amplifier being inserted between an output of the power digital-to-analogue converter and a receive input of the FDD filter unit or the TDD switch.

20. The antenna system according to claim 2, wherein the at least one micro radio utilizes a sampling rate of digital band-pass signals and being 4 times or 4/3 times the RF carrier frequency.

21. The antenna system according to claim 2, wherein the at least one micro radio utilizes a multi-bit format of digital band-pass signals.

22. The antenna system according to claim 2, wherein at least one of the functional sub-units analogue-to-digital converter, power digital-to-analogue converter, transmit clock oscillator unit, clock oscillator unit, receive clock oscillator unit, and digital transceiver of the at least one micro radio are monolithically integrated by micro-electronic means.

23. The antenna system according to claim 2, wherein the at least one micro radio is monolithically integrated by micro-electronic means or as a multi-chip module.

24. The antenna system according to claim 1, wherein the digital radio unit comprising the at least one micro radio and the at least one hub is monolithically integrated by micro-electronic means or as a multi-chip module.

25. The antenna system according to claim 1, wherein the at least one micro radio is proximately connected to one or two antenna elements.

26. The antenna system according to claim 1, wherein the digital radio unit comprises a plurality of micro radios each being proximately connected to one or two antenna elements.

27. The antenna system according to claim 26, wherein the digital radio unit further comprises at least one micro sniffer being proximately connected to at least one monitoring antenna, the micro sniffer being useable for antenna calibration.

28. The antenna system according to claim 1, wherein the digital radio unit is connected to a digital radio server by at least one optical fibre.

29. The antenna system according to claim 1, wherein the digital radio unit and the at least one antenna element are integrated on a single circuit board.

30. The antenna system according to claim 1, whereby said processing and routing of digital radio signals and control signals performed by said hub is software controllable.

31. The use of an antenna system according to claim 1 within a mobile communications network.

32. A computer program product embodied on a computer-readable medium and comprising executable instructions for the manufacture of the antenna system of claim 1.