An enhanced frequency-agile radio for avoiding undesired signal energy, based on a prediction, by scanning an available radio spectrum, measuring a receiver output, identifying an occupied portion of the available spectrum, predicting a level of undesired signal energy in a future scan, and storing the prediction. Enhancements provided by the frequency-agile radio include lowered implementation complexity appropriate for very low cost receivers and transceivers, reduced size due to elimination o...

In wireless local area networks utilizing frequency-hopping between different channels spaced over an allotted frequency band, two or more groups of transceivers in close proximity may be arranged to operate satisfactorily with the full bandwidth available to each by arranging that their hop sequences are kept separate. This may be achieved by arranging for the hop sequence of one group or of each group to skip at intervals from one point to another in the sequence, chosen at random.

An acknowledgement paging system is described which fits within the existing infrastructure of a paging network and which provides low cost manufacture and low power operation while still enabling the acknowledgement paging over long distances. The acknowledgement paging system consists of a standard paging transmitter and a plurality of remote paging units which respond to a page using frequency-hopped spread-spectrum differential bi-phase shift keying communications. The plurality of pagers ar...

A multilevel optical receiver can comprise a plurality of comparators that generally correspond with the number of levels in a multilevel data stream. Each comparator can be individually controlled and fed a decision threshold in order to decode a multilevel signal. The multilevel optical receiver can generate a statistical characterization of the received symbols in the form of a marginal cumulative distribution function (CDF) or probability density function (pdf). This characterization can be ...

An acknowledgement paging system is described which fits within the existing infrastructure of a paging network and which provides low cost manufacture and low power operation while still enabling the acknowledgement paging over long distances. The acknowledgement paging system consists of a standard paging transmitter and a plurality of remote paging units which respond to a page using frequency-hopped spread-spectrum differential bi-phase shift keying communications. The plurality of pagers ar...

A radio transmission system including many radio transmitters using frequency hopping carriers to intermittently transmit very short messages indicative of status of sensors associated with the transmitters. In operation, a time interval generator included in a transmitter generates pulses activating the transmitter at time intervals according to a predetermined algorithm. When activated, the transmitter transmits a message at one or several different frequencies. The frequencies are changed acc...

An information provision exchange service system that can securely prevent the transmission of information that can be used to identify a user to another party and enable users to provide and exchange information between themselves free from confidentiality concerns. A server checks registered personal information to determine whether or not information that can be used to identify any of the users using a plurality of communication terminals is included in information exchanged between the comm...

An optical receiving device capable of outputting a control signal and a data signal received as an optical signal, even if a received optical power of an optical signal inputted via an optical fiber fluctuates. An optical-to-electrical conversion section converts the optical signal inputted via the optical fiber to an electrical signal. A received optical power detection section detects a received optical power of the optical signal. A detection level setting section outputs a first detection l...

A cordless telephone arranged for operation in a frequency hopping system includes multiple portable units configured for operation with a base unit and with each other by having the base unit pseudo randomly select from a plurality of communication channels available in the frequency hopping system a different starting channel for each one of the portable units. Each portable unit then provides initial communications with the base unit over the selected starting channel of the portable unit. Fo...

A scanning method for receiving a signal in a frequency hopped communication system that transmits a packet having N segments that are encoded with an error correction code that allows recovery of a packet even if e segments are erasures. A receiving station continuously scans the first p (1.ltoreq.p.ltoreq.e+1) channels, testing each channel for the existence of a transmission. If detected, a segment is received, and then the receiving station sequences through the remaining channels, receiving...