A technique for spread-spectrum communication which uses more than one mode and more than one frequency band. Selectable modes include narrowband mode and spread-spectrum mode, or cellular mode and microcellular mode. Selectable frequency bands include both licensed and unlicensed frequency bands, particularly frequency bands including the 902-928 MHz, 1850-1990 MHz, and 2.4-2.4835 GHz frequency bands. Spread-spectrum communication channels are 10 MHz or less in width. The frequency band onto which spread-spectrum signals are encoded may be changed upon a change in environment or other control trigger, such as establishment or de-establishment of communication with a private access network. A multi-band transmitter comprises a single frequency synthesizer and a frequency source (e.g., a local oscillator), coupled to a selectable band pass filter. A multi-band receiver capable of monitoring one or more frequency bands comprises bank of bandpass filters and a demodulator comprising a single frequency synthesizer and a frequency source.

Multi-band, multi-mode spread-spectrum communication system

Methods and apparatus are presented that reduce the overall system cost for automotive radar sensing applications through reduction of the number of the radar sensors required. In accordance with aspects of the present invention, one way sensor count reduction can be achieved is through the combination of target range, direction, and velocity determination capability with wide angular field of view coverage within a single sensor unit. One embodiment combines a wide field of view antenna means with a wideband / ultra-wideband / precision-ultra-wideband radar transmitter-receiver and an interferometric direction-finding means into a single sensor unit. Other methods and apparatus are presented.

Methods and apparatus for automotive radar sensors

A system for time division duplex communication over a single frequency band wherein guard time overhead is reduced by active adjustment of reverse link transmission timing as a function of round trip propagation delay. Responding to a polling message from the base station, a user station seeking to establish communication transmits a reply message. The base station using a propagation delay calculator (812) calculates the distance of the user station by measuring the propagation delay with respect to receipt of the reply message and a timing control unit (806) and transmitter (807) for sending a timing adjustment command to the user station instructing it to advance or retard its timing. Thereafter, the base station monitors the user station transmissions and periodically commands it to adjust its timing in a like manner. The user station transmits a control preamble at the start of each time slot to allow the base station to perform round trip timing calculations and adjustment of the user station's power or antenna selection.

Timing adjustment control for efficient time division duplex communication

A method and system for conducting rapid control traffic in a time division multiple access (TDMA) communication system comprises a base station communicating with a plurality of user stations in assigned time slots of a time frame. For bearer traffic, time slots are assigned to particular user stations for an extended duration. In unassigned time slots, the base station transmits a general polling message indicating availability of the time slot. A user station desiring to hand off communication from one base station to another uses multiple available time slots at the target base station for exchanging control traffic messages with the target base station. The next available time slot is indicated by a slot pointer in the header of each general polling message to facilitate rapid exchange of control traffic messages. During handover, the user station may establish a new link with the target base station before relinquishing the existing communication link with the old base station.

Communication system with fast control traffic

A system for time division multiplexed communication over a single frequency band in which guard time overhead is reduced by active adjustment of reverse link transmission timing as a function of round trip propagation time. In one embodiment, during a first portion of a time frame, a base station issues a single burst segmented into time slots comprising data directed to each user station. After a single collective guard time, the user stations respond, one by one, in allocated time slots on the same frequency as the base station, with only minimal guard times between each reception. In order to prevent interference among the user transmissions, the base station measures the round trip propagation time for each user station and commands the user stations to advance or retard their transmission timing as necessary. To establish the initial range of a new user station, a short message is sent by the new user station during the collective guard portion (or, alternatively, during an available time slot), from which the base station calculates the propagation delay and hence the distance of the user station. Messages sent from the base station to the user stations may be interleaved so as to reduce the effects of potential noise or interference.

Efficient communication system using time division multiplexing and timing adjustment control

In a method and system in which data is time-divisionally transmitted from a plurality of base stations to a plurality of mobile subscribers at different frequencies corresponding to the base stations, a given mobile subscriber switches a reception frequency during a time period in which no data originating to the given mobile subscriber is transmitted from the base station having a frequency presently used by the given mobile subscriber, and tests a reception condition at the switched frequency so as to select an optimal reception frequency.

Method and system for switching radio frequency

A portable phone having a recording function to which this invention is applicable comprises a plurality of memories, a switching unit, and a reproducing unit. Each of the memories is used for endless-recording, as a conversation content audio data during the telephone conversation. The switching unit can switch the memories from a first memory of the memories to a second memory of the memories so that the second memory endless-records the audio data instead of the first memory which endless-records, as the conversation content, the audio data until then. The reproducing unit is used for reproducing the conversation content that the first memory endless-records before being switched by the switching unit.

Portable phone having recording function for recording call-audio with using the minimum capacity of memory

Portable telephone with record function

of EP1209884A portable phone having a recording function to which this invention is applicable comprises a plurality of memories, a switching unit, and a reproducing unit. Each of the memories is used for endless-recording, as a conversation content, audio data during the telephone conversation. The switching unit can switch the memories from a first memory of the memories to a second memory of the memories so that the second memory endless-records the audio data instead of the first memory which endiess-records, as the conversation content, the audio data until then. The reproducing unit is used for reproducing the conversation content that the first memory endless-records before being switched by the switching unit.

Koji Tokunaga

Papers

Method and system for switching radio frequency

Portable phone having recording function for recording call-audio with using the minimum capacity of memory

Portable telephone with record function

Portable phone having recording function for recording call contents and using the minimum capacity of memory