A two-way satellite communications system includes an Earth station communicating with a plurality of remote terminals using a network access protocol that facilitates low power consumption by the terminals. The Earth station generates forward link TDM packet data transmissions on one or more satellite channels, and detects, despreads and decodes multiple concurrent return link slotted CDMA packet transmissions on one or more satellite channels. It communicates through a wired connection with a packet processing center which ultimately both delivers return link packet data to end-customers and receives forward link packet data from end-customers. The remote terminals receive, process and act upon forward link TDM transmissions on one or more satellite channels, and generate slotted spread spectrum CDMA transmissions on the return link on one or more satellite channels. The remote terminals communicate with a local digital data source and/or sink, digitize one or more local analog sensor signals, enter into a sleep mode to minimize the terminal's power consumption, and access the satellite communications network in accordance with the system network access protocol.

Wireless packet data distributed communications system

Method and apparatus for facilitating inter-cell connections, such as during a forward handover or radio link failure (RLF), are disclosed. A user terminal such as a UE may store identity information associated with a source cell, and use this information in accessing target or other cells subsequent to radio link failure so as to facilitate access to context information of the user terminal. A base station may be configured to improve handover performance by associating context information with a newly assigned terminal identity. Handover performance may be enhanced by facilitating connection processing in the event of inability to retrieve user terminal context from a source cell.

Methods and apparatus for facilitating robust forward handover in long term evolution (lte) communication systems

By doping an organic compound functioning as an electron donor (hereinafter referred to as donor molecules) into an organic compound layer contacting a cathode, donor levels can be formed between respective LUMO (lowest unoccupied molecular orbital) levels between the cathode and the organic compound layer, and therefore electrons can be injected from the cathode, and transmission of the injected electrons can be performed with good efficiency. Further, there are no problems such as excessive energy loss, deterioration of the organic compound layer itself, and the like accompanying electron movement, and therefore an increase in the electron injecting characteristics and a decrease in the driver voltage can both be achieved without depending on the work function of the cathode material.

Light Emitting Device

In a mobile communication method according to the present invention includes the steps of: transmitting, from a handover source radio base station to a swithcing center, a handover request including an NCC, a PCI and a K eNB *; changing, at the swithcing center, the NCC, changing, at the swithcing center, the K eNB * on the basis of the PCI, and transmitting, from the swithcing center to the handover target radio base station, the handover request including the changed NCC and the changed K eNB *; generating, at the handover target radio base station, a first key on the basis of the K eNB *; and generating, at the mobile station, the first key on the basis of the NCC and the PCI included in a handover command.

Mobile communication method

System(s) and method(s) are provided for forward handover under radio link failure. A configurable criterion for radio link failure (RLF) is established through a reference threshold for a channel quality metric; the threshold (CQITH) can be determined at least on a quality-of-service basis or a per-terminal basis. A low-overhead indication of RLF is conveyed as a NULL CQI when the channel quality metric is below threshold. Onset of RLF triggers preparation of forward handover (FHO) at a terminal within a predetermined timer, during which normal service can resume if link quality recovers above CQITH. Forward handover is pursued once timer elapses. Preparation at the terminal can be complemented by preparation implemented in advanced to RLF condition, in accordance to a disparate threshold applied to terminal's measurements. Preparation of FHO includes backhaul exchange of operational information like buffered data, and context.

Forward handover under radio link failure

In order to effectively control a time interval of issuing a handoff request from a land site in a mobile communications system, a strength of a signal which is transmitted from a mobile unit located in a service area of said land site, is measured at the land side. A level crossing rate is measured based on the signal transmitted from the mobile unit. A first handoff request is generated if the signal strength falls below a predetermined handoff threshold. Following this, a timer is rendered active for counting an elapsed time after the first handoff request is generated. If the signal strength is detected below the predetermined handoff threshold, a time interval is determined based on the level crossing rate. The relationship between the time interval and the level crossing rate has been previously determined. Thereafter, a second handoff request is generated if the time interval determined in the above exceeds the elapsed time. subsequently, the timer is reset and then the above operations are repeated.

Method and arrangement for reducing the number of handoff requests in a cellular mobile communications system

By detecting a degraded state of wireless transmission quality due to steady occurrence of re-transmission in an early stage to lead to a call connection, a service quality is made sure, an excess time charge on an end user is prevented and wireless resources are utilized efficiently. A base station controller monitors a PDU transmission state in a wireless link to a mobile station in call unit, calculates an occurrence rate of re-transmission as an evaluation value of wireless transmission quality, determines a degradation of the wireless transmission quality when the occurrence rate of re-transmission becomes equal to or larger than a predetermined threshold value and performs a disconnection processing for the call.

Mobile communication system

PURPOSE:To reduce cost by extending a transmission interval of an electric field deterioration signal sent by a communication channel equipment in response to a moving speed of a mobile terminal equipment to the utmost in a range where hand-off is properly executed, thereby reducing number of installed electric field level measurement devices in a radio base station. CONSTITUTION:A communication channel equipment 5 of a radio base station 2 compares an electric field level measured during talking with a predetermined hand-off request threshold level. When the electric field level is less than the hand-off threshold level, the equipment 5 transmits an electric field deterioration signal to a mobile telephone exchange station 1 via a radio base main controller 3 and monitors lapse of time from the transmission of the electric field deterioration signal. When it is required to transmit the electric field deterioration signal again to the equipment 5, the equipment 5 obtains the electric field deterioration signal transmission time interval corresponding to a current level crossing rate from absolute value data stored in advance. The equipment 5 compares the interval with an elapsed time from the preceding transmission of the electric field deterioration signal and when the elapsed time is smaller than the time interval, the electric field deterioration signal is not sent and when larger, the electric field deterioration signal is sent.

Electric field level measurement system

A radio telephone switching control system having control channels which transmit/receive control data betweeen a plurality of movable terminals and a radio base station. The control channels include a mono-functional channel for access which is dedicated to access during data transmission/receiving by calling from the terminals. The control channel also includes a bi-functional channel for paging and access usable as a channel for paging one of the terminals as well as for access. The system contains a base station with a fault detector. Only one kind of control channel information is broadcast in the same service zone. All of the movable stations existing in same service zone scan the first or second range to decide the channel for access or paging according to the received control channel information. The system also sets the mono-functional channel for access and the bi-functional channel for paging and access, when a fault is not detected. Once a fault is detected, the second range is separated from the first range, whereby the mono-functional channel for paging is used only to transmit data for paging from the base station and the mono-functional channel for access is used to transmit/receive data related to actions other than paging to the terminals.

Radio telephone system switching control capability of control channels

A mobile communication system, which is capable of improving a hand-off success rate of a mobile terminal moving in a high speed, and also capable of improving a process capability of a base station during hand-off control operation, is realized. When the mobile terminal, which has moved from one cell to another cell during communication, receives a hand-off instruction signal from a hand-off control unit of a mobile switching center, an electric field level measurement stopping unit stops the electric field level measurement of the forward control channels of the adjoining base stations which has instructed from the original hand-off base station, and also stops the transmission of the electric field level measurement result signal.

Hirofumi Shiotsuki

Papers

Method and arrangement for reducing the number of handoff requests in a cellular mobile communications system

Mobile communication system

Electric field level measurement system

Radio telephone system switching control capability of control channels

Mobile communication system and a hand-off method thereof