Multiaccess techniques for mobile and stationary cellular communications

• US 20060187872A1
• Filed: 02/21/2005
• Published: 08/24/2006
• Est. Priority Date: 02/21/2005
• Status: Abandoned Application

• Current Assignee: Mark James Rich
• Original Assignee: Mark James Rich
• Inventors: Rich, Mark James
• Application Number:
  US10/906,454
• Publication Number:
  US 20060187872A1
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601

Abstract

A wireless communications system connecting multiple senders and multiple receivers through multi-access method utilizing orthogonal frequency division multiplexing techniques. A method of expanding the services provided by delivering asymmetrically higher bandwidth per channel and more channels through orthogonal frequency division multiplexed access methods and quadrature amplitude modulation.

Claims

1. A cellular communication system comprising a cellular infrastructure, a plurality of subscriber stations, a channel assignment method, a forward link method for broadcasting allocations of timeslots and spectrum to the subscriber stations, and a reverse link method for modulating multiple carriers by each subscriber station.

2. The reverse link method of claim one comprising transmitting during an assigned time slot on a plurality of assigned carriers using orthogonal frequency division multiplexing access method.

3. The reverse link method of claim two further comprising combining time slots to increase efficiency by eliminating gaps, and transmitting on adjacent orthogonal frequency division multiplexing carrier bands to increase efficiency by eliminating overhead carriers.

4. The channel assignment method of claim one comprising the steps of firstly dividing up time and spectrum to a plurality of timeslots each containing carriers in a plurality of frequency bands, secondly assigning each subscriber station to a unique time slot and plurality of carriers, thirdly, combining timeslots to increase transmission efficiency by eliminating time gaps, and fourthly combining adjacent frequency assignments to increase transmission efficiency by eliminating overhead carriers.

5. The forward link method of claim four further comprising firstly broadcasting allocations of timeslots and spectrum to the subscriber stations, secondly, modulating data on a plurality of synchronized carriers using quadrature amplitude modulations, and thirdly, transmitting data on multiple carriers using orthogonal frequency division multiplexing.

6. The forward link method of claim four, operating in the beginning portion of a frame, further comprising a first part and a second part, said first part of a cell station transmission where each cell station transmits training and synchronization information comprising sending multiple tones of pure carrier to allow receivers to adjust their reference frequency, secondly sending a special sequence to allow each receiver to update equalization coefficients, thirdly broadcasting timing and identification information for new stations joining the network, and fourth sending information indicating what timeslots are assigned to specific personal stations, wherein each cell station is assigned a fraction of the band commensurate with the amount of forward traffic it needs to send.

7. The subscriber station of claim one comprising a quadrature amplitude demodulator, and an orthogonal frequency division multiplexing receiver.

8. The subscriber station of claim seven further comprising a quadrature phase shift key modulator and an orthogonal frequency division multiplexing transmitter.

9. The cellular infrastructure of claim one comprising a plurality of physically distributed base stations wherein the coverage of signals is overlapping, an access method for orthogonal frequency division multiplexing wherein adjacent base stations may use carriers without interference, a plurality of encoding modulation methods, and a duplex method of time division wherein a plurality of timeslots may be combined for efficiency.

10. The duplex method of claim nine comprising dividing each time frame into a forward portion of a time frame and a reverse portion of a time frame enabling the reuse of frequency allocations in the transmission from base stations to subscriber stations and in the transmission from subscriber stations to base stations which thereby improves efficiency by using more frequencies at any point in time.

11. The duplex method of claim nine further comprising dividing each time frame into a plurality of time slots which are allocated to transmit to subscriber stations and to transmit from subscriber stations to base stations, the timeslots allowing combination of a plurality of timeslots into one transmission wherein the removal of gaps between timeslots and use of a single header for a combined timeslot improves the efficiency of transmission by replacing gaps and headers with data.

12. The duplex method of claim nine further comprising quadrature amplitude modulation encoding and quadrature phase shift key modulation encoding wherein the more data intensive direction may use a more complex and costly transmission modulation and the less data intensive direction may use a compact and economical transmission modulation.

13. The access method of claim nine comprising assigning a plurality of carriers to the transmission from a first base station to a first subscriber station wherein the carriers are not used by a second base station adjacent to the first base station to transmit to a second subscriber station increasing the efficiency of using the available spectrum by allowing adjacent base stations to transmit on closely spaced carriers.

14. The access method of claim nine comprising dividing the spectrum available to a base station into frequency bands and assigning the carriers available in a plurality of frequency bands to a single transmission increasing the use of spectrum by reducing the number of overhead carriers or more closely spacing carriers for a single higher bandwidth transmission.

15. The cellular infrastructure of claim nine further comprising transmission of synchronization information from a plurality of base stations to a plurality of subscriber stations during the forward link allowing the subscriber stations to determine which base station has a stronger signal and self select which base station it should associate with.

16. The cellular infrastructure of claim nine further comprising a method to divide time and pluralities of orthogonal carriers into a large number of combinations creating a larger number of simultaneous communication opportunities from subscriber stations to base stations.

17. The cellular communications system of claim one further comprising a mobile radio communications network infrastructure selected from among the following:

personal handyphone system, land mobile radio, police radio, tdma cellular system, and two way paging.

18. A cellular telephone system comprising a conventional personal handyphone system infrastructure, base stations, subscriber stations, a time division duplex system, an orthogonal frequency division multiplexing access method forward link and an orthogonal frequency division access reverse link.

19. The duplex system of claim eighteen comprised of standard timeslots consisting of 16 symbols, 8 symbols of synchronization and header information followed by 8 symbols of traffic and double timeslots, wherein eliminating one guardtime interval and the use of a single header allows up to 25 symbols, wherein a total of 28 single slot or 14 double slots or a mixture of the two are allowed in a 2.5 ms reverse link interval.

20. The access method of claim eighteen using 5 carriers to carry a 32 kbps transmission wherein some number of carriers are set aside for interference mitigation and using 8 symbols every 2.5 ms, wherein restricting operation to quadrature phase shift keying modulation provides 2 bits per symbol per carrier to carry the traffic and additional carriers are used for synchronization and isolation between adjacent, unsynchronized subscriber station transmissions.

21. The system of claim eighteen further comprising an 8 symbol payload in the standard timeslot and using four carriers to increase the volume of information delivered.

22. The system of claim eighteen further comprising a 25 symbol payload in the double timeslot and using four carriers wherein efficiency is increased because a single traffic header is used and because the interslot guard time is eliminated.

23. The forward link of claim eighteen further comprising training and synchronization information and payload, said training and synchronization information comprising multiple tones of pure carrier to allow receivers to adjust their reference frequency, secondly a special sequence to allow each receiver to update equalization coefficients, thirdly timing and identification information for new stations joining the network, and fourth information indicating what timeslots are assigned to specific personal stations, wherein each cell station is assigned a fraction of the band commensurate with the amount of forward traffic it needs to send.

24. A process of synchronizing a subscriber station to base stations, the steps comprising:

simultaneously demodulating the entire band, during the pure tone transmission, to select the cell station with the best signal strength if it has not been in prior communication with a specific cell station, wherein new entrants to the network will scan until the training sequence is detected.

25. The process of claim twenty-four further consisting of continuing to monitor the training sequences of other base stations in the area, wherein said monitoring allows the subscriber station itself to make hand-off decisions as it moves from one cell coverage area to another.

26. The system of claim eighteen further comprising a base station transmitting data in quadrature amplitude modulation on the forward link in the authorized portions of the spectrum to further increase forward link capacity.