Subscriber RF telephone system for providing multiple speech and/or data signals simultaneously over either a single or a plurality of RF channels

• US 5,734,678 A
• Filed: 10/02/1996
• Issued: 03/31/1998
• Est. Priority Date: 03/20/1985
• Status: Expired due to Fees

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Paneth, Eric, Handzel, Mark J., Morley, Steven Allan, Avis, Graham M.
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): GLUCK, JEFFREY WILLIAM
• Application Number:
  US08/724,930
• Time in Patent Office: 545 Days
• Field of Search: 375/240, 375/280, 375/283, 375/377, 370/330, 370/436, 370/465, 370/468, 370/478, 379/58, 379/59, 379/63, 455/33.1, 455/53.1, 455/54.1
• US Class Current: 375/240
• CPC Class Codes: H04B 7/04 using two or more spaced independent antennas
• CPC Class Codes: H04B 7/0865 Independent weighting, i.e. weights based on own antenna reception parameters
• CPC Class Codes: H04J 3/0647 Synchronisation among TDM nodes
• CPC Class Codes: H04J 3/0682 by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging
• CPC Class Codes: H04L 1/0001 Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0007 by modifying the frame length
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/0061 Error detection codes
• CPC Class Codes: H04L 1/0084 Formats for payload data
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 1/1642 Formats specially adapted for sequence numbers
• CPC Class Codes: H04L 1/18 Automatic repetition systems, e.g. Van Duuren systems
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 5/143 for modulated signals H04L5/1469 takes precedence
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 28/14 : using intermediate storage
• CPC Class Codes: H04W 28/24 : Negotiating SLA [Service Level Agreement]; Negotiating QoS [Quality of Service]
• CPC Class Codes: H04W 28/26 : Resource reservation
• CPC Class Codes: H04W 36/12 : Reselecting a serving backbone network switching or routing node
• CPC Class Codes: H04W 4/18 : Information format or content conversion, e.g. adaptation by the network of the transmitted or received information for the purpose of wireless delivery to users or terminals
• CPC Class Codes: H04W 40/02 : Communication route or path selection, e.g. power-based or shortest path routing
• CPC Class Codes: H04W 52/0216 : using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/20 : using error rate
• CPC Class Codes: H04W 56/00 : Synchronisation arrangements
• CPC Class Codes: H04W 72/02 : Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 72/04 : Wireless resource allocation
• CPC Class Codes: H04W 72/044 : based on the type of the allocated resource
• CPC Class Codes: H04W 72/0446 : Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/0453 : Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/12 : Wireless traffic scheduling
• CPC Class Codes: H04W 72/23 : in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 74/04 : Scheduled access hybrid access H04W74/02
• CPC Class Codes: H04W 76/10 : Connection setup
• CPC Class Codes: H04W 84/00 : Network topologies
• CPC Class Codes: H04W 84/14 : WLL [Wireless Local Loop]; RLL [Radio Local Loop]
• CPC Class Codes: H04W 88/08 : Access point devices
• CPC Class Codes: Y02D 30/70 : in wireless communication networks

Abstract

A terrestrial Rf telephone system provides a plurality of voice signal channels on a plurality of forward direction carrier frequencies, each carrier frequency having an associated predetermined bandwidth which is designed to accommodate one analog voice signal, and each carrier frequency containing a plurality of slots. The system includes a base station having a plurality of circuit paths for receiving a plurality of forward direction digitized voice signals; a plurality of compressors for compressing the voice signals; a processor for assigning each of the compressed voice signals onto a dynamically assigned frequency/slot; a plurality of channel controllers, each for sequentially combining the compressed digitized voice signals into a single transmit channel bit stream, with each compressed voice signal occupying a respective repetitive sequential time slot in the transmit channel bit stream; and a plurality of modulators for modulating the carrier frequencies. A portion of the carrier frequency within a portion of each slot remains unmodulated by the transmit channel bit stream to provide a phase reference signal.

Claims

1. An apparatus for providing a plurality of voice signal channels on a plurality of forward direction carrier frequencies of a terrestrial RF telephone system, each of said forward direction carrier frequencies containing a plurality of slots, each of said forward direction carrier frequencies having an associated predetermined bandwidth which is designed to accommodate one analog voice signal channel therein, said apparatus comprising:

a base station comprising;

a plurality of circuit paths for receiving a plurality of forward direction digitized voice signals from a public switched telephone network;

a plurality of compressors for respectively compressing each of said forward direction digitized voice signals by analyzing the speech content of said forward direction digitized voice signals and by using voice compression to form respective forward direction compressed digitized voice signals, each compressed digitized voice signal having a bit rate of less than 16 kb/s;

a processor for assigning each of the compressed digitized voice signals a dynamically assigned frequency/slot;

a plurality of channel controllers, each for sequentially combining said respective forward direction compressed digitized voice signals into a single transmit channel bit stream, with each of the respective forward direction compressed digitized voice signals occupying a respective repetitive sequential time slot in the transmit channel bit stream;

a plurality of modulators for modulating each of said forward direction carrier frequencies with said transmit channel bit stream, each of said modulators using M-ary modulation to transmit at least 2 bits/symbol, wherein a carrier frequency within a portion of each said slot remains unmodulated by said transmit channel bit stream; and

a transmitter for RF transmitting said forward direction modulated frequency carriers to at least one subscriber station, each of said transmitted modulated forward direction carrier frequencies residing within said predetermined bandwidth and capable of carrying in the forward direction at least two bidirectional simultaneous conversations;

wherein at least part of said slot portion unmodulated with said transmit channel bit stream provides a phase reference signal.

2. An apparatus as in claim 1 wherein each said compressor produces a set of coefficients and an additional signal which are contained in each forward direction compressed voice signal, and which are used to reconstruct a respective forward direction digitized voice signal.

3. An apparatus as in claim 1 further comprising means responsive to call requests from said public switched telephone network associated with each of said plurality of digitized voice signals for establishing call paths for each of said plurality of digitized voice signals through said apparatus.

4. An apparatus as in claim 3 wherein said circuit paths comprise,

an exchange for switching the digitized voice signals through respective compressors and to an assigned time slot;

and

said processor comprises means responsive to said call requests for providing a slot/frequency assignment signal indicating which slot and frequency a compressed digitized voice signal is to occupy, thereby assigning a compressed digitized voice signal to a time slot and frequency in said transmit channel bit stream, said means for providing a slot/frequency assignment signal including a memory which stores information concerning which slots/frequencies have been so assigned, said means for providing a slot/frequency assignment signal accessing said memory upon receipt of an incoming call request;

wherein said means responsive to said slot/frequency assignment signal causes said exchange to complete the necessary connections so that an incoming digitized voice signal is routed through a respective compressor to said dynamically assigned time slot in said transmit channel bit stream.

5. An apparatus as in claim 1 wherein said apparatus also receives a plurality of voice signal channels on reverse direction carrier frequencies of said terrestrial RF telephone system, each of said reverse direction carrier frequencies having an associated predetermined reverse frequency channel bandwidth which is designed to accommodate one analog voice signal channel and together with said forward direction carrier frequency provides at least two simultaneous bidirectional conversations between said base station and two or more subscriber stations, said base station further comprising:

a receiver for receiving a respective receive channel signal, said receive channel signal having a different carrier frequency than said forward direction carrier frequency and residing within said predetermined reverse frequency channel bandwidth, said receive channel signal having a receive channel bit stream M-ary modulated thereon;

a plurality of demodulators each for demodulating one of said receive channel signals to provide said receive channel bit stream containing separate reverse direction compressed signals in different respective repetitive sequential slot positions, each of said reverse direction compressed signals being produced at a subscriber station by voice compression coding techniques applied to a respective subscriber generated digitized voice signal;

a signal separator for separating said reverse direction separate compressed signals from said receive channel bit stream;

a plurality of decompressors for respectively decompressing the reverse direction separate compressed signals using voice compression decoding techniques to produce separate reverse direction decompressed digitized voice signals; and

circuit paths for applying said separate reverse direction digitized voice signals to said public switched telephone network.

6. An apparatus as in claim 5 wherein each said compressor produces a set of coefficients and an additional signal which are contained in each forward direction compressed voice signal and which represent and can be used to reconstruct a respective forward direction digitized voice signal.

7. An apparatus as in claim 5 wherein a portion of said reverse carrier frequency in each slot remain unmodulated with said received channel bit stream.

8. An apparatus as in claim 7 wherein at least a part of the slot portion unmodulated with said reverse channel bit stream is modulated with a predetermined bit pattern for use in symbol timing.

9. An apparatus as in claim 1 wherein said forward direction carrier frequencies are modulated with 16-ary modulation.

10. An apparatus as in claim 1 wherein said forward direction carrier frequencies are modulated with 32-ary modulation.

11. An apparatus as in claim 1 wherein said forward direction carrier frequencies are PSK modulated with 64-ary modulation.

12. An apparatus as in claim 1 wherein said plurality of modulators include means for M-ary modulating at least one of said respective forward direction carrier frequencies with a first M-ary modulation level and for M-ary modulating at least one of said respective forward direction carrier frequencies with a second M-ary modulation level, said first and second M-ary modulation levels being different.

13. An apparatus as in claim 1 wherein each slot contains a respective forward direction compressed digitized voice signal, at least one of said slots having a different time duration from others of said slots.

14. An apparatus as in claim 1 further comprising means for establishing the number of time slots which occur on each of said forward frequency channels.

15. An apparatus as in claim 1 wherein at least part of said slot portion unmodulated with said transmit channel bit stream is modulated by a predetermined bit pattern for use in symbol timing.

16. An apparatus for providing at least one data information signal on one of a plurality of forward direction carrier frequencies of a terrestrial RF telephone system, each of said forward direction carrier frequencies containing a plurality of slots, each of said forward direction carrier frequencies having an associated predetermined bandwidth which is designed to accommodate one analog voice signal channel therein, said apparatus comprising:

a base station comprising;

a plurality of circuit paths, on one of said circuit paths said at least one data information signal from a public switched telephone network is carried, the information rate of said data information signal being less than 16 kb/s;

a processor for assigning said data information signal a dynamically assigned frequency/slot;

a plurality of channel controllers, one of said controllers including said data information signal into a single transmit channel bit stream, with the data information signal occupying a respective repetitive sequential time slot in the transmit channel bit stream;

a plurality of modulators, one of which modulates the assigned forward direction carrier frequency with said transmit channel bit stream, said modulator using M-ary modulation to transmit at least 2 bits/symbol, wherein the carrier frequency within a portion of said slot remains unmodulated by said data information signal; and

a transmitter for RF transmitting said forward direction modulated frequency carrier to at least one subscriber station, each of said transmitted modulated forward direction carrier frequencies residing within said predetermined bandwidth and capable of carrying in the forward direction at least two bidirectional simultaneous data information signals;

wherein at least part of said slot portion unmodulated with said data information signal provides a phase reference signal.

17. An apparatus as in claim 16 wherein said at least part of said slot portion unmodulated with said data information signal is modulated by a predetermined bit pattern for use in symbol timing.

18. An apparatus for providing a plurality of voice signal channels on a plurality of forward direction carrier frequencies of a terrestrial RF telephone system, each of said forward direction carrier frequencies containing a plurality of slots, each of said forward direction carrier frequencies having an associated predetermined bandwidth which is designed to accommodate one analog voice signal channel therein, said apparatus comprising:

a base station comprising;

a plurality of circuit paths for receiving a plurality of forward direction digitized voice signals from a public switched telephone network;

a plurality of compressors for respectively compressing each of said forward direction digitized voice signals by analyzing the speech content of said forward direction digitized voice signals and by using voice compression to form respective forward direction compressed digitized voice signals, each compressed digitized voice signal having a bit rate of less than 16 kb/s;

a processor for assigning each of the compressed digitized voice signals a dynamically assigned frequency/slot;

a plurality of channel controllers, each for sequentially combining said respective forward direction compressed digitized voice signals into a single transmit channel bit stream, with each of the respective forward direction compressed voice signals occupying a respective repetitive sequential time slot in the transmit channel bit stream;

a plurality of modulators for modulating each of said forward direction carrier frequencies with said transmit channel bit stream, each of said modulators using M-ary modulation to transmit at least 2 bits/symbol, wherein a carrier frequency within a portion of each said slot remains unmodulated by said transmit channel bit stream; and

a transmitter for RF transmitting said forward direction modulated frequency carriers to at least one subscriber station, each of said transmitted modulated forward direction carrier frequencies residing within said predetermined bandwidth and capable of carrying in the forward direction at least two bidirectional simultaneous conversations;

wherein at least part of said slot portion unmodulated with said transmit channel bit stream is modulated by a predetermined bit pattern for use in symbol timing.

19. An apparatus for providing at least one data information signal on one of a plurality of forward direction carrier frequencies of a terrestrial RF telephone system, each of said forward direction carrier frequencies containing a plurality of slots, each of said forward direction carrier frequencies having an associated predetermined bandwidth which is designed to accommodate one analog voice signal channel therein, said apparatus comprising:

a base station comprising;

a plurality of circuit paths, on one of said circuit paths said at least one data information signal from a public switched telephone network is carried;

the information rate of said data information signal being less than 16 kb/s;

a processor for assigning said data information signal a dynamically assigned frequency/slot;

a plurality of channel controllers, one of said controllers including said data information signal into a single transmit channel bit stream, with the data information signal occupying a respective repetitive sequential time slot in the transmit channel bit stream;

a plurality of modulators, one of which modulates the assigned forward direction carrier frequency with said transmit channel bit stream, said modulator using M-ary modulation to transmit at least 2 bits/symbol, wherein the carrier frequency within a portion of said slot remains unmodulated by said data information signal; and

a transmitter for RF transmitting said forward direction modulated frequency carrier to at least one subscriber station, each of said transmitted modulated forward direction carrier frequencies residing within said predetermined bandwidth and capable of carrying in the forward direction at least two bidirectional simultaneous data information signals;

wherein at least part of said slot portion unmodulated with said data information signal is modulated by a predetermined bit pattern for use in symbol timing.