Assignment of a carrier frequency in an SDMA radio system

US5732075A · kind A · utility

Assignee

• Alcatel N.V. · NL

Inventors

• Michael Tangemann · Leonberg, DE
• Cornelis Hoek · Stuttgart, DE
• Heinz Schlesinger · Mundelsheim, DE

Key dates

• Filing date: Jan 22, 1996
• Grant date: Mar 24, 1998
• Expiry date: Jan 22, 2016

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04W72/541
• WIPO field: Digital communication
• WIPO sector: Electrical engineering

Abstract

To assign a carrier frequency to different mobile stations in a conventional Space Division Multiple Access (SDMA) radio system, the stations are differentiated according to the direction in space from which they transmit radio signals to a base station. In addition, the distances between the base station and the mobile stations are compared. To prevent interference at the receiving site (base station BTS), according to the invention a carrier frequency (f) is assigned to the different mobile stations (MS1 to MS3) only if the directions in space (.THETA.1 to .THETA.3) are sufficiently different and the receive levels (P1 to P3) of the radio signals are sufficiently equal. To that end, each mobile station (MS1 to MS3) is assigned a guard area, which encompasses at least a preselected solid angle (lobe width w) and at most a preselected level space (dynamic range S). Any further mobile station wanting a radio link with the base station on the same carrier frequency (f) must be located in a permissible zone (Z) between the guard areas, which comprises a level range (zP) that is common to all preceding mobile stations. A further guard area is defined with each further connection, and t…