Ubiquisys Limited

Percello Ltd.

Cisco Technology, Inc.

Alan Carter

Stephen Whittaker

Aminu Wada Maida

Rafy Carmon

Amir Appel

Alon Shechter

Ami Appel

Benny Arviv

Stephen Whitakker

There is described a method of controlling a basestation in a cellular wireless communications network, the method comprising, within the basestation, autonomously and dynamically adapting a maximum value for a total transmit power of the basestation, such that interference between the basestation and other access points in the vicinity is minimized.

Access point power control

In a femtocell basestation of a cellular communications network, there is a potential difficulty that the basestation may be unable to select a scrambling code for its transmissions, without the risk of interference with other basestations using the same scrambling code. The femtocell basestation receives from a management system a list comprising at least one allowed scrambling code for femtocell basestations, and also detects, in information broadcast by at least one macrocell basestation, at least one allowed scrambling code available in an area containing the basestation. If it is determined that use of each scrambling code that is allowed and is available in an area containing the basestation would cause interference with another femtocell basestation, a parameter is set to ensure that a user equipment would perform a location update when moving between the coverage areas of said basestation and the other femtocell basestation. The parameter may be a MIB and/or SIB value tag.

Scrambling code selection

A basestation for a cellular communications network is intended to provide coverage over a small area, which may be within an area that already has cellular coverage from one or more existing basestations. The basestation is therefore able to detect signals transmitted from the other basestations, in order to make measurements of the radio environment. In particular, the basestation may be able to receive signals periodically on the system downlink frequencies.

Receiving signals from surrounding basestations

Control unit within a femtocell base station is arranged to detect a transmission collision situation and resolves it by adjusting the timing of the transmission signal and consequently the frame position gradually over time. The adjustment (or shift) is performed in a slow enough rate such that the User Equipments currently connected (camped) to the femtocell base station remain connected. Additionally, a method is also provided. The method comprises: detecting neighboring base stations; detecting frame boundaries of the transmitting signal of each detected neighboring base station; calculating optimal transmit position; setting transmit position to calculated optimal transmit position; and maintaining optimal transmit position by gradually adjusting transmit position over time. In case, detecting neighboring base stations is not possible, the method comprises: detecting absolute time drifting in view of an absolute accurate time reference and maintaining constant absolute transmit position by gradually adjusting transmit position over time.

Avoiding transmitter collision sessions in femtocells arrays

A basestation in a cellular communication system corrects frequency errors in signals generated within the basestation. The frequency errors may be corrected on the basis of signals transmitted by one or more other basestation within the network. As an alternative, the basestation may request information from one or mobile devices that are also able to detect transmissions from other basestations.

Basestation for cellular communication system

In a cellular communications network, it may be desirable for a large number of basestations to share one or a small number of scrambling codes. When a basestation identifies a desired scrambling code, which is also being used by another nearby basestation, steps are taken such that a location area update is triggered whenever a mobile communications device moves from a coverage area of the nearby basestation into a coverage area of said basestation. Further, the basestation establishes a first cell, using the desired scrambling code, and also establishes a second cell also served by the basestation, using a second scrambling code. By ensuring that mobile devices are preferentially served by the second cell, the possibility of interference with the nearby basestation is reduced.

Establishing colocated second cell using a second scrambling code by a femto base station

A basestation in a cellular communication system corrects frequency errors in signals generated within the basestation. The frequency errors may be corrected on the basis of signals transmitted by one or more other basestations within the network. As an alternative, the basestation may request information from one or more mobile devices that are also able to detect transmissions from other basestations.

Growing community of inventors

Swindon, United Kingdom

Alan Carter