Method and communications system for estimating an error covariance matrix for the downlink in cellular mobile radio telephone networks with adaptive antennae

• US 20030162501A1
• Filed: 11/22/2002
• Published: 08/28/2003
• Est. Priority Date: 05/22/2000
• Status: Active Grant

• Current Assignee: Nokia Siemens Networks GmbH & Company KG (Nokia Corporation)
• Original Assignee: Nokia Siemens Networks GmbH & Company KG (Nokia Corporation)
• Inventors: Haardt, Martin, Mecklenbraeuker, Christoph
• Granted Patent: US 7,555,266 B2
• Time in Patent Office: Days
• US Class Current: 455/63.1
• CPC Class Codes: H04B 7/0615 of weighted versions of same signal
• CPC Class Codes: H04B 7/0617 for beam forming

Abstract

Data is transmitted in a radio communication system having two or more base stations that are located in the network and having additional radio stations, which are each connected to one of the base stations via radio interfaces. At least one first base station has an antenna array with a multitude of antenna elements and with a signal processing device for the directional transmitting-receiving of data. The first base station temporally overlays data to a radio station, which is connected to the base station, for the transmission of data from an external base station to an external radio station connected thereto. The transmission of data from the first base station is also received from the external radio station. The objective is to reduce the amount of disturbance to the external radio station caused by transmissions from the base station in the downlink direction. To this end, the transmitting power of the antenna array of the base station is reduced in the direction toward the external radio station after a transmission of a training signal of the transmitted signal for the external radio station and after the reception of an assignable training signal of the external radio station.

Claims

1. A method for data transmission in a radio communication system having two or more network-side base stations (BS, BSn) and a multiplicity of further radio stations (MS, MSn) that are connected in each case to one of the base stations (BS, BSn) via air interfaces (V1, V2, Vn),

at least a first one of the base stations (BS) having an antenna arrangement with a multiplicity of antenna elements (A1-A4) and a signal processing device (DSP) for transmitting/receiving data as a function of direction,

the first of the base stations (BS) transmitting data to a radio station (MS) connected to it in a fashion overlapping in time with the transmission of data from a foreign base station (BSn) to at least one foreign radio station (MSn) connected thereto, and

the transmission of data from the first base station (BS) being noticed as disturbance for the foreign radio station (MSn), characterized

in that the transmit power of the antenna arrangement of the base station (BS) in the direction of the at least one foreign radio station (MSn) is reduced after a transmission of an item of information via the transmitted signal of the foreign radio station (MSn) and after the reception of an assignable signal of the foreign radio station (MSn).

2. The method as claimed in claim 1, in which transmitted to the base station (BS) as information relating to the transmitted signal of the at least one foreign radio station (MSn) is/are the training signal(s) (ma-n) thereof and, optionally, the uplink time slot (UL-ts) thereof.

3. The method as claimed in claim 1 or 2, in which the information relating to the transmitted signal of the foreign radio station (MSn) is transmitted via network-side devices (L1, RNM, L2) in the radio communication system.

4. The method as claimed in a preceding claim, in which in order to set the distribution of the spatial transmit power at the base station (BS) there is determined or estimated a spatial error covariance matrix R_I^(l) which yields a beam-shaping vector (w^(k)) as solution to the optimization problem

5. The method as claimed in claim 4, in which the solution to the optimization problem is performed by solving the general eigenvalue problem with positively semi-definitely Hermitian matrix R_S^(k) and positively definite Hermitian matrix R_I^(k),

6. The method as claimed in a preceding claim, in which the transmission of data in the FDD or TDD mode is performed in time slots and/or using the multi-slot method.

7. The method as claimed in a preceding claim, in which the information relating to the transmitted signal of the foreign radio station (MSn) is transmitted to the base station (BS) regularly or after setting up a connection of the foreign base station (BSn) to the foreign radio station (MSn).

8. The method as claimed in a preceding claim, in which transmitted in addition as information relating to the transmitted signal of the foreign radio station (MSn) are the downlink time slots (DL-ts) in which the foreign radio station MSn receives data from its base station (BSm).

9. The method as claimed in a preceding claim, in which, in addition, the disturbing interference that does not originate from the radio communication system itself is also taken into account with the aid of the associated covariance matrix.

10. The method as claimed in a preceding claim, in which information relating to training signals (ma-n) and uplink time slots (ts0-ts8) of the foreign network-side base station (BSn) is transferred to the base station (BS) in a radio communication system with asynchronous switching points (SP) if these time slots are used by the base station (BS) in the downlink (DL).

11. Radio communication system, in particular for carrying out a method as claimed in a preceding claim, having

two or more network-side base stations (BS, BSn),

a multiplicity of further radio stations (MS, MSn) that are connected in each case to one of the base stations (BS, BSn) via air interfaces (V1, V2, Vn), and

at least one antenna arrangement with a multiplicity of antenna elements (A1-A4) and a signal processing device (DSP) for transmitting/receiving data as a function of direction, in the case of at least a first one of the base stations (BS),

the first of the base stations (BS) transmitting data to a radio station (MS) connected to it in a fashion overlapping in time with the transmission of data from a foreign base station (BSn) to a foreign radio station (MSn) connected thereto, and

the transmission of data from the first base station (BS) also being received by the foreign radio station (MSn), characterized

in that the signal processing device (DSP) is designed for reducing the transmit power of the antenna arrangement of the base station (BS) in the direction of the foreign radio station (MSn) after a transmission of an item of information via the transmitted signal of the foreign radio station (MSn) and the reception of an assignable signal of the foreign radio station (MSn).

12. The radio communication system as claimed in claim 11, in which an association table (MEM) buffers data (ma-n) of the foreign radio station (MSn) referring to downlink time slots DL-ts assigned to the latter, in particular the information via the transmitted signal thereof, after the transmission thereof, and provides them to the signal processing device (DSP).