Telefonaktiebolaget Lm Ericsson (Publ)

Stig Roland Bodin

Ingrid V Nordstrand

Lotta Voigt

Georg William Chambert

Lars Kalle Linden

Per-Ola Gaasvik

Harald Kallin

Lars M Andersson

Ulf Goran Forssen

Lars Magnus Lindroth

Carl Patrik Cerwall

Johan Karoly Galyas

Sven-Olof L Jonsson

Cecilia S Hedin

Lars-Erik Svedin

Karl R Forsselius

A method and device avoid repeated registration attempts to register on PLMNs which do not allow registration for a mobile terminal while permitting attempts to register on PLMNs earlier inserted in a list of a number of identities of rejected PLMNs in a storage in the terminal but which may allow registration at a later time. At least a part of the list is erasable to be erased from time to time. Surplus identities of rejected PLMNs on a non-volatile part of the list are transferred to the erasable part of the list at overflow of the non-erasable list.

Method and device in a mobile station for avoiding repeated registration

The present invention relates to the technique of handover in mobile telephony. A new Transcoder and Rate Adaptation Unit (100 FIG. 3) is introduced which provides two uplink (230, 250 respectively, FIG. 3) and two downlink (240, 260 respectively, FIG. 3) channels. The use of these two channels (230, 250 respectively, FIG. 3) on the uplink during handover provides for the use of distributed handover on the uplink. The result minimizes the audible interruption during handover by minimizing the loss of Traffic Channel frames to what is possible within the GSM standard. Additionally, interruption of the speech or background noise during these lost frames is masked by an error concealment algorithm, since the Transcoder and Rate Adaptation Unit (100 FIG. 3) still has information from the Base Transceiver Station responsible for transmission before the handover.

Quality-based handover

In a cellular mobile telecommunication system, particularly a Global System for Mobile Communications (GSM) system, a method and apparatus determine the geographical position of a mobile station. The distance between the mobile station and a radio base station is estimated from the propagation delay. The propagation delay is determined according to the present method when the mobile station sends access bursts to the base station, which measures the access delay of the arrived bursts in the same way as an ordinary handover. However, no confirmation of received access bursts is sent from the base station to the mobile station and therefore the handover attempt is terminated. The connection between the mobile station and the previous base station is re-established. The measured access delay is proportional to the propagation delay and thereby also to the distance to the mobile station. The mobile position can be determined with good accuracy if values from at least three base stations are obtained, although with less accuracy if only two values are obtained. Also, an access delay measured by earlier known methods can be used together with measurements achieved with the present method to determine the mobile position.

Method and apparatus for mobile station geographical location

A method for establishing a new broadcast control channel carrier frequency within a cell without disturbing ongoing call traffic is disclosed. A cell having a base station transmitting broadcast control channel data over an existing BCCH carrier frequency establishes a second BCCH carrier frequency within the cell. During a first time period BCCH data is transmitted on the existing first BCCH carrier frequency. During a second time period, both the existing and new BCCH carrier frequencies carry BCCH data to enable surrounding mobile stations to detect and recognize both carriers. The transmission of the old BCCH carrier frequency is then discontinued during a third time period, such that the broadcast control channel data is only transmitted on the new BCCH carrier frequency.

Method for changing BCCH carrier frequency without disturbing ongoing

The present invention relates to a method of registering a mobile station in a cellular mobile radio system in which areas, each including a plurality of cells, form registration areas. Each registration area (RA1, RA2, RA3, . . . ) has its own identity (X). According to the proposed method, individual location areas are defined whenever registering a given mobile station with the intention of avoiding an unnecessarily high number of registrations in border areas of the different registration areas. A location area may have the form of a list of registration areas (X1, X2, X3, . . . ), which is stored in a mobile station (MS), or may be stored in the system (HLR, MSC) and transmitted to the mobile station (MS) via a base station (BS) in a given registration area, in conjunction with registration of the mobile station in this area. A new registration is made only if the mobile station enters a service area that belongs to a registration area whose identity (X) is not found on the stored list of registration areas (X1, X2, X3, . . . ).

Registration method in a cellular mobile radio system

A method for broadcasting information in a cellular communication system comprising at least one base station with an antenna array and a plurality of mobile stations is disclosed. The common information is preprocessed to create orthogonal signals. The orthogonal signals are then beam formed so that the orthogonal signals are delivered to the different elements in the array antenna. The orthogonal signals are transmitted and then received at at least one mobile station. The signals are then processed at the mobile station to decipher the common information from the orthogonal signals.

Orthogonalizing methods for antenna pattern nullfilling

A method of setting up and handing off calls in a mobile cellular radio system in which consideration is given to the load capacity of several types of channels. The communication system determines the available capacity of the different groups of channels in the communication system whenever a new call needs to be set up. The system then assigns the new call to the group of channels with the most available channels if the requesting mobile station is a multi-mode mobile station, or the system hands off a multi-mode mobile station from a first group of channels to a second group of channels or vice versa to create free channels for calls from single mode mobiles.

Method for redistributing dual mode mobile units to extended channel

In a cellular mobile radiotelephone system having a plurality of cells providing radio coverage by a plurality of base stations and having a plurality of mobile stations, the location of a mobile station with respect to cell boundaries is identified using measurements, performed at the mobile station or at selected cells, of transmissions from the cells or transmissions from the mobile station. When a cell is found that meets a specified standard with respect to a call connection in progress according to a first radio-signal criterion, a handoff candidate cell is selected according a second different radio-signal criterion. When no cell is found that meet the specified standard, a cell is selected according to the first radio-signal criterion. Handoff to the selected cell is attempted if that cell is not presently handling that call. More particularly, the first radio-signal criterion may be signal strength and the second radio-signal criterion may be path loss. When a cell is found that meets the signal-strength criterion, the cell is determined to have sufficient signal strength margin so that the path loss criterion may be used instead. As mentioned above, use of the path loss criterion has the advantages of conserving power, reducing interference, and allowing effective cell boundaries to remain fixed. When no cell is found that meets the signal-strength criterion, the call connection is determined to be signal-strength limited such that the signal strength criterion is used to select the cell having the greatest signal strength.

Radiotelephone locating and handoff using alternative criteria

Radio link failure

A method for registering traffic data from mobile stations in a mobile telecommunication system. The mobile telecommunication system includes mobile switching centers and connected with these, base station controllers, so-called primary- and secondary base station controllers. Base stations are connected to the base station controllers, each base station covering a cell and each base station controller thereby covering a cell area containing several cells. Traffic data from a selected mobile is stored in the primary base station controller of the mobile. A trace invocation message is sent from the primary base station controller to the secondary base station controller, via the mobile switching center, when the mobile moves to a cell handled by the secondary base station controller. Registration of traffic data is thereafter effected in the secondary base station controller.

Method for registering traffic data in a telecommunication system

The invention relates to a method of controlling, in a cellular mobile radio communication system, the output power of radio signals transmitted from a transmitter to a receiver located in the same cell as the transmitter. The method comprises controlling the output power of the transmitter in dependence of a parameter, that is characteristic of the distance between transmitter and receiver, to approximately follow, from a predetermined maximum output power that is transmitted when the distance between the transmitter and receiver is the maximum within the cell, a first function that monotonically decreases with decreasing distance and approaches a predetermined minimum output power as the distance approaches zero, so that the power of the transmitted radio signals as received by the receiver from a minimum received power, that is received when the distance between transmitter and receiver is the maximum within the cell, approximately follows a second function that monotonically increases with decreasing distance and approaches a maximum received power as the distance approaches zero.

Method of controlling output power in a mobile radio communication system

A method and system for ensuring that handoff requests take priority over new cell requests to engage voice channels assigned to a particular target cell are provided. A certain number of channels are reserved for handoff requests. However, if no channels, reserved or unreserved, are available, handoff requests to a particular target cell are stored in a corresponding queue for a predetermined period of time. Thus, when voice channels become available, they are seized in order to satisfy the handoff requests stored in that queue. If the handoff queue is empty, new call requests to a target cell may be assigned to available voice channels.

Growing community of inventors

Sp.ang.nga, Sweden

Stig Roland Bodin