Equipment for wireless telephone transmission

• US 4,682,350 A
• Filed: 04/10/1986
• Issued: 07/21/1987
• Est. Priority Date: 07/06/1982
• Status: Expired due to Fees

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Akerberg, Dag E.
• Primary Examiner(s): Lev, Robert
• Application Number:
  US06/850,222
• Time in Patent Office: 467 Days
• Field of Search: 179/2 E, 179/ 2 EA, 179/2 EC, 370/29, 370/109, 381/34
• US Class Current: 455/403
• CPC Class Codes: H04B 1/56 with provision for simultaneous communication in two directions
• CPC Class Codes: H04M 1/733 with a plurality of base stations connected to a plurality of lines for selection in cordless PBX H04W84/16

Abstract

A method of connecting audio information between a base telephone unit which is stationary and a portable unit associated therewith, the method involving dividing the communication time for audio information into first and second periods. During each first period, transmitting audio information from one of the units to the other over a radio channel and during each second period transmitting in reverse direction. The duration of the periods is a function of which transmitter is active at a given time.

Claims

1. In a telephone communication system including at least a first unit and a second unit for audio information wherein each of the units includes a radio transmitter and a radio receiver, the method of radio communicating audio information between the units comprising the steps of dividing telephone audio information communication time into a plurality of equal time slots, dividing each time slot into a first and second period, during each first period radio transmitting from one of said units over a radio channel having a given range of frequencies to the other of said units and during each second period radio transmitting from said other unit to said one unit over said radio channel, the duration of said periods with respect to each other being a function of which transmitter is active at a given time.

2. The method of claim 1 further comprising the step of storing any audio information received by the first unit from other than the second unit, during a second period for transmission and during the first period occurring thereafter and the step of storing any audio information received by the second unit from other than the first unit during a first time period related thereto for transmission during the next period occurring thereafter.

3. The method of claim 1 wherein the transmission of audio information by the first unit is at greater than real time speed and the information stored by the first unit is first transmitted during said first period followed by the transmission of the said audio information being received during said first period and the transmission of audio information by the second unit is at greater than real time speed and the information stored by the second unit is first transmitted during said second period followed by the transmission of the said audio information being received during said second period.

4. The method of claim 3 wherein the radio receivers are of the homodyne type operating with a given frequency and said transmission steps comprise modulating a carrier signal having a carrier frequency in said given range of frequencies.

5. In a system including at least a base unit connected to a telephone system for interchanging telephone audio information and a mobile unit for interchanging telephone audio information wherein each of the units includes a radio transmitter and a radio receiver, the method of radio communicating telephone audio information between the units comprising steps of dividing the telephone audio information communication time into a plurality of equal time slots, dividing each time slot into a first and second period, during each first period radio transmitting over a radio channel having a given range of frequencies from the base unit any telephone audio information being received from the telephone system during the time slot associated with said first period and during each second period radio transmitting from the mobile unit any telephone audio information being received from the user during the time slot associated with said second time period, the duration of said periods with respect to each other being a function of which transmitter is active at the time.

6. Apparatus for connecting a telephone user to a telephone system comprising

a base unit connected to the telephone system and a mobile unit carried by the user;

said base unit comprising an antenna means, a time-controlled send-receive switch means a radio transmitter means including time compression means connected between said switch means and said antenna means for transmitting audio telecommunications information from the telephone system to the mobile unit at higher than real time speed, and a radio receiver including time expansion means connected between said antenna means and said send-receive switch means for forwarding to the telephone system via said send-receive switch means at real time speed audio telecommunication information received from the mobile unit at higher than real time speed, said mobile unit comprising an antenna means, a time-controlled send-receive switch means, means for connecting said switch means to the user, a radio transmitter means including time compression means connected between said switch means and said antenna means for transmitting audio telecommunication information from the user to the base unit at higher than real time speed, and a radio receiver means including time expansion means connected between said antenna means and said send-receive switch means for forwarding to said user via said send-receive switch means at real time speed audio telecommunications information received from the base unit at higher than real time speed, and said switch means being synchronized to operate such that only one of the two radio transmitters is transmitting at any given time, said send-receive switch means including control means for controlling the duration of send and receive modes and degree of time compression perfomed by said time compression means as a function of the presence or absence of audio telecommunication information for transmission.

7. The apparatus of claim 6 wherein the audio telecommunication information is in the form of analog signals and said compression means comprises, in serially connection, an analog-to-digital converter, a digital time compressor and a digital-to-analog converter.