Telefonaktiebolaget Lm Ericsson (publ)

Ericsson Gmbh

Ericsson Ge Mobile Communications Inc.

Jacobus C Haartsen

Paul W Dent

Paul Wilkinson Dent

Rajaram Ramesh

Heino Jean Wendelrup

Ravinder David Koilpillai

Carlos E Vidales

Troy M Bourgeois

Lars B Nord

A secure radio personal communication system and method includes a base station which relays cellular verification signals between a wide area cellular network and a cellular terminal via the wire telephone network. Thus, cellular telephone calls which are routed to a cellular terminal via a base station, when the cellular terminal is within a local region covered by the base station, may be exchanged between the cellular network and cellular terminal over the wire telephone network. Calls from the wide area cellular network which are routed through the base station can thus employ the same security systems and methods which are employed by the wide area cellular network. Signals between the base station and the cellular terminal are preferably exchanged when the cellular terminal is parked in the base station. Verification and encryption signals may be exchanged. The same signals may be used for enhanced security when the base station is relaying wire network calls to the cellular terminal when the cellular terminal is in the local region. Alternatively, separate verification and encryption protocols may be used.

Secure radio personal communications system and method

Mobile handover between a private radio communications network connected to the public switch telephone network and a public land mobile network also connected to the public switch telephone network are provided by a radio communications mobile terminal supporting simultaneous communication connections between the two uncoordinated networks. The mobile terminal monitors a base station of the public land mobile network during idle frames of communication connections with the private radio communications network, thereby synchronizing the mobile terminal to both the base of the public land mobile network and the private radio communications network. Call interruption is prevented during handover by maintaining simultaneous communications with the private radio communications network and the public land mobile network through the use of two half-rate channels or dual-slot communications where both the public land mobile network and private radio communications network operate pursuant to compatible TDMA standards. Handover is initiated when the mobile terminal detects a signal quality which violates a predetermined switching criteria and passes the PSTN phone line number of the private radio communications network to the base station of the public land mqbile network which in turn requests re-routing of the call from the PSTN switch.

Radio communications system and method for mobile assisted handover

A data and message retrieval communications system utilizes a base station such as a PC or cellular phone to transmit received messages and stored data in accordance with an operator customized data configuration and transmission scheme. The system includes a remote receive-only communication unit that receives and processes the signal from the base station in accordance with an operator customized data configuration and retrieval scheme. The remote unit preferably includes a receiver having an antenna, a processor that processes the transmission signal received by the receiver, a memory storing the personal data and data corresponding to the transmission signal, and a display interface unit enabling an operator to interface with the processor programmed to access and control the receiver, the memory and the display interface in accordance with the operator customized data configuration and retrieval scheme. In one arrangement, the remote communication unit is embodied in a wristwatch for maximum portability.

Data and message retrieval communications system including remote

In a multi-reuse level cellular communications system, a channel is assigned for use by a mobile unit by first determining whether the mobile unit is a non-enhanced mobile unit or an enhanced mobile unit. Then a determination is made as to the type of communication service being requested. A minimum link quality required by the mobile unit can then be established based on factors that include the mobile unit type and the type of communication service being requested. A base station that has the necessary receiver detection capabilities and transceiver processing capabilities is then selected, and a channel, corresponding to a highest reuse plan, available to the base station is assigned to the call.

Channel assignment in enhanced fixed-plan mobile communications systems

A multi-carrier radio system in which pairs of subcarriers are positioned in frequency such that each subcarrier in a pair is the image of the other subcarrier in the pair. By making each subcarrier the image of another subcarrier, the radio system of the present invention permits highly integrated low-IF transceiver implementation. In an exemplary embodiment, a multi-carrier transceiver includes an integrated receiver comprising a first mixer for mixing an input signal with a local oscillator signal to produce an in-phase downconverted signal. Additionally, a first phase shifter phase-shifts the local oscillator signal to produce a quadrature local oscillator signal, and a second mixer mixes the input signal with the quadrature local oscillator signal to produce a quadrature downconverted signal. Thereafter, a second phase shifter phase-shifts, or rotates, the quadrature downconverted signal to produce a rotated quadrature downconverted signal. A summer sums the in-phase downconverted signal and the rotated quadrature downconverted signal to produce an upper band detection output signal, and a subtractor subtracts the rotated quadrature downconverted signal from the in-phase downconverted signal to produce a lower band detection output signal. The exemplary multi-carrier transceiver also includes a compatible integrated transmitter for generating appropriate multi-carrier signals.

Multi-carrier radio system and radio transceiver implementation

Methods and systems for allocating control channels in a radiocommunication system are disclosed. Control channels are associated with dedicated traffic channels. The allocation history of dedicated traffic channels can be monitored to determine which dedicated traffic channels are allocated most frequently to a base station. A control channel can then be allocated to the base station based on the allocation history of the associated dedicated traffic channels.

Stabilized control channel planning using loosely coupled dedicated

A system and method for allowing intercom and multiple voice channel communication within a private telephone system employing a private base station and a multiplicity of standard cellular terminals is disclosed. Full duplex intercom communications between two users within the private telephone system may be facilitated by use of two half-rate channels, one channel transceiver on even-numbered TDMA transmission frames and another channel transceiver on odd-numbered transmission frames, both from respective terminals to a private base station, which mediates the communication therebetween. Multiple voice channels are also provided within the private telephone system, allowing two users on two separate channels to communicate with respective remote wireline users simultaneously.

System and method for providing intercom and multiple voice channels in

The present invention relates to a method and arrangement in an ad-hoc network for synchronizing a multiple of radio transceiver arrangements with different characteristics that make use of a common air interface. Each transceiver arrangement comprises at least two transceivers which mutually communicate via a radio transmission link. All transceivers synchronize to a common synchronization signal comprising two staggered beacon pulse series signals (TX.sub.1, TX.sub.2) which have the same repetition rate. The transceivers synchronize their internal timers which control the signal transmission from the transceivers, to the strongest one of the two beacon pulse series signals (TX.sub.1, TX.sub.2) by listening during one of the corresponding sets of time windows (RX.sub.1, RX.sub.2). Between the reception of two beacon pulses, each transceiver transmits beacon pulses itself, thus contributing to the generation of the other beacon pulse series signal, on which other transceivers can lock.

Method and arrangement for radio communication

A multi-channel Automatic Retransmission Query (ARQ) methods transmits data packets from a source to a destination over a communication link that is subdivided into a number of channels. A network using the multi-channel ARQ method sequentially multiplexes the data packets at the source and transmits them over corresponding channels. The network applies a stop-and wait ARQ method on each one of the channels and determines whether the destination has positively acknowledged a previously transmitted data packet. If not, the network retransmits only the data packets that are not positively acknowledged.

Multi-channel automatic retransmission query (ARQ) method

An allocation method and system for allocating a least-interfered communications link between a cellular mobile station and a private radio base station within a cellular system is disclosed. A set of candidate carrier frequencies are first selected and ordered by the amount of interference present within the cellular system, and a subset thereof selected. A second set of candidate frequencies and associated timeslots are then selected from the subset and ordered by the amount of interference present in the private radio system environment, and a second subset thereof selected. A plurality of discrete hop lists for each timeslot are then formed, and one of the hop lists exhibiting the least amount of interference is then selected to be applied in the communications link.

Method and system for autonomously allocating a frequency hopping

The invention relates to synchronizing in communication systems by using a sequential correlation technique. A digital sequence known to the receiver, a so-called signature, is allocated a plurality of segments. The segments are correlated, segment for segment, in a correlator (300) which is equally as long as the segment. The segments may have the same or different bit patterns. When a first segment is received in the correlator (300) and the correlation value of this segment exceeds an associated threshold value, the segment is accepted as received and is saved in a memory (308) in response to a signal from the control unit (311). A timer (319) is set to a time point that corresponds to the length of the segments. There is then correlated a second segment whose correlation value on the signal from the timer (319) is added (304) to the value stored in the memory (308). If the sum exceeds an associated threshold value, the sum is stored in the memory (308). Detection continues in this way. When the sum of the correlation values of all segments have exceeded the threshold value of the last segment, there is generated a sync. time pulse signal (Ts). Should a threshold value not be exceeded, it is assumed that a wrong signature has been received, and detection of the first segment is recommenced.

Method and an arrangement for receiving a symbol sequence

Establishing a connection between a paging unit and a standby unit in a channel hopping communications system includes activating the standby unit for an activation time period out of every standby time period. During each activation time period, the standby unit monitors a selected channel for receipt of a paging message. The selected channel is selected from a plurality of channels, and, for each subsequent activation time period, the selected channel is a subsequent one of the plurality of channels as specified by a hopping sequence and an internal clock. A page train is repeatedly transmitted from the paging unit to the standby unit, until a response is received from the standby unit. Each page train includes a plurality of paging messages, each paging message being transmitted on a different one of a subset of the plurality of channels. Selection of a page train for transmission by the paging unit may be based on an estimate of the standby unit's internal clock.

Access technique of channel hopping communications system

Radio beacon transmission between a private radio communications base station and a mobile terminal within the transmission range of the private radio communications base station designed to prevent interference with overlapping uncoordinated private radio communications networks is provided by jittered beacon transmission. The private base station transmits radio beacon bursts at jittered time intervals, which vary pseudo-randomly to prevent repeated radio beacon collisions between uncoordinated private radio communications networks with overlapping transmission ranges. The beacon time jittering is performed pseudo-randomly in a pattern which is associated with a base station identification value. The mobile terminal derives the base station associated identification value and status information from a received radio beacon and determines if the base station is available for communications with the mobile terminal. The mobile terminal further synchronizes with the jittered base station beacon transmissions based on the pre-determined jitter generation function associated with the base station identification value derived from the received radio beacon. The mobile terminal is thereby able to readily maintain synchronization with one or more private radio communications network base stations without losing synchronization due to repeated radio beacon burst collisions between the base stations.

Radio communications systems and methods for jittered beacon transmission

An allocation method and system for allocating a least-interference communications channel between a cellular system and a private radio system within the cellular system. A set of candidate channels are first selected and ordered by the amount of interference present within the cellular system, and a subset thereof is selected. A second set of candidate channels are then selected from the subset and ordered by the amount of interference present in the private radio system environment, and a safe channel subset thereof is selected. That channel exhibiting the least amount of interference is then selected from the safe channel subset as the communications channel.

Method and system for autonomously allocating a cellular communications

If no uncorrectable errors are discovered in a received data packet, an acknowledgment is sent back to the sender. Conversely, if the data packet contains uncorrectable errors, no acknowledgment is sent, forcing a re-transmission of that data packet in accordance with an automatic repeat request (ARQ) procedure. In such cases, sets of unquantized signal values relating to received data packets having uncorrectable errors are stored. When two or more sets of unquantized signal values for the same received data packet (as re-transmitted) have been stored, the unquantized signal values are numerically combined on a bit-by-bit basis, and then quantized to regenerate a combined data packet. If no uncorrectable errors are discovered in that combined data packet, an acknowledgment is sent back to the sender. Otherwise, no acknowledgment is sent, forcing another data packet re-transmission.

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Staffanstorp, Sweden

Jacobus C Haartsen