Abstract: A frequency hopping spread spectrum telecommunication system is provided, which selects carrier frequencies based on the number of active slots. The duration that carriers have been employed is then based on the number of active slots (401, 402), rather than the number of frames (22). Thus, non-interfered with carriers can be used more often than interfered with carriers, thereby improving voice quality.

Abstract: A method for avoiding interference in a wireless telecommunication system is provided. The method includes providing communication between a first and second component at an initial frequency. A plurality of successive line quality indicators is determined at a line quality monitor of the first component. Consecutive line quality indicators are summed over a predetermined time to determine a slow hop count. A determination is made as to whether the slow hop count is greater than a slow hop threshold. A determination is made as to whether to provide communication with the first component at a second frequency when the slow hop count is greater than the slow hop threshold. This determination is based on a power level of the second component and a communication strength received from the second component at the first component. A signal is communicated from the first component to the second component requesting the second component to provide communication at the second frequency.

Abstract: Providing an audio broadcast for a TDMA system. During a single time slot, an audio message is broadcast from a base art and received at a number of portable arts. An audio broadcast command is generated by designating the single time slot and then transmitted to the plurality of portable parts. An additional portable part transmits a broadcast origination signal and the audio message to the base part which transmits the audio broadcast command to the portable parts. by assigning a time slot other than the designated time slot to a portable part, the portable part does not broadcast audio messages during the designated time slot. More than three receiving time slots and more than three sending time slots are divided out for the base art that includes the designated time slot. The audio broadcast command is transmitted during at least two of the more than three sending time slots.

Abstract: The invention relates to a method and a device for digital data radiotransmission between a fixed station (1) and at least one mobile station (2, 3) at one or several carrier frequencies (F1, F2 . . . ), wherein the data is transmitted in several time slots (Z1, Z2 . . . ) according to the time-multiplex technique. A specific amount of time is required to change from one carrier frequency to another carrier frequency using a slow-hopping HF module. The data is transmitted in an active followed by an inactive time slot during which no data is transmitted and which is sufficient for the HF module to program the frequency for the following active time slot. According to the invention, an inactive time slot is shorter than an active time slot.

Abstract: A programmable band-pass filter in a radio-frequency receiver. The band-pass filter has a bandwidth substantially covering a channel bandwidth. Once the appropriate channel in use is determined, the frequency band of the band-width filter is set to correspond to it.

Abstract: According to the invention, a mobile radio is provided for radio transmission in time-division multiplex frames, where these frames each alternatively have active time slots (Z1) in which data are transmitted, and inactive time slots (Z2) in which no data are transmitted. The time duration of the active time slots is, in this case, twice the duration of the inactive time slots. The mobile radio (1, 2) has a burst mode controller (13) which provides the time-division multiplex frame structure for transmission, and a clock preset device (18), which presets the clock rate for the burst mode controller (13). The clock rate which the clock device (18) presets for the burst mode controller (13) is twice as high during the inactive time slots (Z2) as during the active time slots (Z1).

Abstract: A system and method for call screening in a wireless telephone system. When a call is received on an answering machine (17) associated with a base part (11), the user at a portable part (12) may select a call screen button (19). The resulting signal is received at the base part (11), which then enters a broadcast mode. The incoming answering machine message is broadcast to all handsets (12, 14, 16). In a TDMA system, an audio message is broadcast from a base part (11) during a single time slot of a time division. The user at a particular portable part may then select a pick up button to pick up the call.

Abstract: The present invention comprises a system and method for improving voice quality of cordless communications. The system comprises at least one mobile unit having circuitry for maintaining an individual communication link with a base station. The system also has logic residing in the base station for selecting a frequency to maintain the communication link, monitoring parameters relating to the quality of the frequency, and performing data correction on the frequency in response to the monitored quality of the frequency.

Abstract: A frequency downconversion receiver is provided that does not require predictive filtering for signal acquisition and synchronization. A sync block modulates a voltage-controlled oscillator (VCO) with twice the frequency of the incoming modulated receive signal. From this, the bit position of the incoming data can be determined. The value of the incoming data can be determined from whether the VCO output and the demodulator output have consecutive predetermined values.

Abstract: A method is provided for interfacing telecommunication devices. A base unit is connected to a landline for wireless communication. The base unit has a power supply operating at a power supply frequency. A mobile unit is provided for wireless communication with the base unit. The base unit is interfaced to the mobile unit using an interface protocol that has a plurality of frames. Each frame is for transmitting signals from the mobile unit to the base unit and from the base unit to the mobile unit. The frames have a specified frame length. An interference frequency is detected at either the base unit or the mobile unit. The interference frequency is compared with the power supply frequency. The frames are synchronized with the power supply and the specified frame length is adjusted based on the power supply frequency when the interference frequency and the power supply frequency are substantially the same.

Abstract: A method and system are disclosed for avoiding bad frequency subsets in a frequency hopping cordless telephone system. A base station communicates with the handsets using frequencies selected from active frequency subsets. Bad frequency subsets are avoided by monitoring the air interface between the base station and handsets for errors in active frequency subsets. Errors in each active frequency subset are counted during a short-term interval using an associated short-term error counter and during a long-term interval using an associated long-term error counter. After each short-term interval, it is evaluated whether any of the short-term error counters has a value that is greater than a defined threshold. After each long-term interval, it is evaluated whether any of the long-term error counters has a value greater than an error count for a blocked frequency subset.

Abstract: A method and system are provided for synchronizing wireless communication devices. The method and system involve providing a first unit and a second unit for communication over a wireless communication link. Further, an identical identifier is assigned to the first and second units. Also, a data message is constructed having control data. The data message includes a plurality of data bytes and a portion of the control data corresponds to the identifier. The data message is split into a plurality of message portions and the message portions are transmitted from the first unit to the second unit. The message portions are received at the second unit. Control data from the message portions is assembled to form a control message at the second unit. The identifier portion of the control message is compared with the identifier assigned to the second unit. When the identifier portion of the control message matches the identifier assigned to the second unit, the second unit enters an in-synchronization state.

Abstract: According to the invention, a method and an arrangement is provided for digital radio transmission of data between a fixed station (1) and at least one mobile station (2, 3) at one of a plurality of carrier frequencies (f1, f2, etc.) the data being transmitted in time slots (Z1, Z2 etc.) using time-division multiplex method (TDMA) and, in particular if so-called slow hopping RF modules are used, the change from one carrier frequency to another carrier frequency requiring at least a time period corresponding to one time slot. According to the invention, the data are transmitted in two successive active time slots (Z1, Z2) which are followed by an inactive time slot, in which no data are transmitted. The transmission in two successive time slots (Z1, Z2) takes place at the same carrier frequency.

Abstract: A cordless communication system employing an air interface capable of providing both isochronous (e.g., voice) and asynchronous (e.g., data) communication is described. The air interface combines advantages of the HomeRF SWAP and WDCT protocols to provide high quality voice and data service without unnecessarily increasing the complexity of the cordless communication system.

Abstract: A cordless digital telephone system which allows audio broadcasts is provided. Time division multiple access (TDMA) cordless phone systems provide a base unit which is able to provide connections for a plurality of mobile units, such as handsets. With time division, the mobile units are synchronized to different time slots. A broadcast mode is provided that causes the mobile units to be placed in a receive only mode and to synchronize to the same time slot where a broadcast message is sent.

Abstract: A programmable band-pass filter in a radio-frequency receiver. The band-pass filter has a bandwidth substantially covering a channel bandwidth. Once the appropriate channel in use is determined, the frequency band of the band-width filter is set to correspond to it.

Abstract: A frequency hopping spread spectrum telecommunication system is provided, which selects carrier frequencies based on the number of active slots. The duration that carriers have been employed is then based on the number of active slots (401, 402), rather than the number of frames (22). Thus, non-interfered with carriers can be used more often than interfered with carriers, thereby improving voice quality.

Abstract: A cordless telephone system employing a base station (202) as slave and a plurality of handsets (204a, 204b) as masters is provided. The handsets (204a, 204b) periodically poll the base station. The base station (202) responds with acknowledge slots and also timing information whereby the handsets (204a, 204b) can adjust their poll timing so as avoid interfering with one another. If an active connection is set up between the base station (202) and a handset (204a), the other handset (204b) is not allowed to poll during the connection, effectively functioning as a system slave for the duration of the connection. Thus, the second handset (204b) stays synchronized to the first handset (204a) and listens until the connection is completed, whereupon it resumes normal functioning.

Abstract: A cordless communication system for use in a wireless network that is capable of providing efficient use of available frequency spectrum within a given physical space is disclosed. The cordless communication system is comprised of a central unit and at least two remote units that are capable of direct communication with each other via wireless connections assigned and coordinated by the central unit.

Abstract: A base station (12) according to an implementation of the invention is adapted to identify a public power supply frequency, e.g., 50 Hz or 60 Hz. The base station (12) then adapts its frame and slot structures to the power supply frequency. The base station (12) transmits a synchronization word on a data channel, and also transmits a signal indicative of the power supply frequency. The mobile unit (14, 16) receives the data channel and the information indicative of the frequency. The mobile unit (14, 16) then adapts its frame and slot structure appropriately. After the link is established, and if periodic interference is detected, transmission occurs during the inactive period of the interference.