US 6,684,057 B2 · Systems and methods for terrestrial reuse of cellular satellite frequency spectrum

Abstract

A satellite radiotelephone frequency can be reused terrestrially by an ancillary terrestrial network even within the same satellite cell, using interference cancellation techniques. Moreover, the ancillary terrestrial network can use a modified range of satellite band forward link frequencies for transmission, to reduce interference with out-of-band receivers. A modified range of satellite band forward link frequencies that is used by the ancillary terrestrial network can include only a subset of the standard satellite band forward link frequencies to provide a guard band, can include power levels that monotonically decrease as a function of increasing frequency and/or can include two or more contiguous slots per frame that are left unoccupied and/or are transmitted at reduced maximum power. Time division duplex operation of the ancillary terrestrial network may also be provided over at least a portion of satellite band return frequencies. Full or partial reverse mode operation of the ancillary terrestrial network also may be provided, where at least some of the forward link and return link frequencies are interchanged with the conventional satellite forward link and reverse link frequencies.

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Drawings

Claims305

Dependent claims

A satellite radiotelephone system comprising:

a space-based component that is configured to receive wireless communications from a first radiotelephone in a satellite footprint over a satellite radiotelephone frequency band;
an ancillary terrestrial network that is configured to receive wireless communications from a second radiotelephone in the satellite footprint over the satellite radiotelephone frequency band, the space-based component also receiving the wireless communications from the second radiotelephone in the satellite footprint over the satellite radiotelephone frequency band as interference along with the wireless communications that are received from the first radiotelephone in the satellite footprint over the satellite radiotelephone frequency band;
and
an interference reducer that is responsive to the space-based component and to the ancillary terrestrial network, and that is configured to reduce the interference from the wireless communications that are received by the space-based component from the first radiotelephone in the satellite footprint over the satellite radiotelephone frequency band, using the wireless communications that are received by the ancillary terrestrial network from the second radiotelephone in the satellite footprint over the satellite radiotelephone frequency band.

1 more element

A gateway for a satellite radiotelephone system that includes a space-based component that is configured to receive wireless communications from a first radiotelephone in a satellite footprint over a satellite radiotelephone frequency band and an ancillary terrestrial network that is configured to receive wireless communications from a second radiotelephone in the satellite footprint over the satellite radiotelephone frequency band, the space-based component also receiving the wireless communications from the second radiotelephone in the satellite footprint over the satellite radiotelephone frequency band as interference along with the wireless communications that are received from the first radiotelephone in the satellite footprint over the satellite radiotelephone frequency band, the gateway comprising:

an interference reducer that is responsive to the space-based component and to the ancillary terrestrial network, and that is configured to reduce the interference from the wireless communications that are received by the space-based component from the second radiotelephone in the satellite footprint over the satellite radiotelephone frequency band, using the wireless communications that are received by the ancillary terrestrial network from the second radiotelephone in the satellite footprint over the satellite radiotelephone frequency band.

A multiple mode ancillary terrestrial component for a satellite radiotelephone system that includes a space-based component that is configured to receive wireless communications from radiotelephones over a first range of satellite band return link frequencies and to transmit wireless communications to the radiotelephones over a second range of satellite band forward link frequencies that is spaced apart from the first range, the multiple mode terrestrial component comprising:

an electronics system that is selectively configured to receive wireless communications from the radiotelephones over the first range of satellite band return link frequencies and to transmit wireless communications to the radiotelephones over the second range of satellite band forward link frequencies that is spaced apart from the first range in a first mode of operation and to transmit wireless communications to the radiotelephones over a modified second range of satellite band forward link frequencies in a second mode of operation.

A satellite radiotelephone communication method comprising:

receiving wireless communications at a space-based component from a first radiotelephone in a satellite footprint over a satellite radiotelephone frequency band;
receiving wireless communications at an ancillary terrestrial network from a second radiotelephone in the satellite footprint over the satellite radiotelephone frequency band, the space-based component also receiving the wireless communications from the second radiotelephone in the satellite footprint over the satellite radiotelephone frequency band as interference along with the wireless communications that are received from the first radiotelephone in the satellite footprint over the satellite radiotelephone frequency band;
and
reducing the interference from the wireless communications that are received by the space-based component from the second radiotelephone in the satellite footprint over the satellite radiotelephone frequency band using the wireless communications that are received by the ancillary terrestrial network from the second radiotelephone in the satellite footprint over the satellite radiotelephone frequency band.

1 more element

Dependencies are inferred from the claim text.

Description9,471 words

Summary2,928 words

#This invention relates to radiotelephone communications systems and methods, and more particularly to terrestrial cellular and satellite cellular radiotelephone communications systems and methods.

#Satellite radiotelephone communications systems and methods are widely used for radiotelephone communications. Satellite radiotelephone communications systems and methods generally employ at least one space-based component, such as one or more satellites that are configured to wirelessly communicate with a plurality of satellite radiotelephones.

#A satellite radiotelephone communications system or method may utilize a single antenna beam covering an entire area served by the system. Alternatively, in cellular satellite radiotelephone communications systems and methods, multiple beams are provided, each of which can serve distinct geographical areas in the overall service region, to collectively serve an overall satellite footprint. Thus, a cellular architecture similar to that used in conventional terrestrial cellular radiotelephone systems and methods can be implemented in cellular satellite-based systems and methods. The satellite typically communicates with radiotelephones over a bidirectional communications pathway, with radiotelephone communication signals being communicated from the satellite to the radiotelephone over a downlink or forward link, and from the radiotelephone to the satellite over an uplink or return link.

Brief description of the drawings12 figures

#FIG. 1 is a schematic diagram of cellular radiotelephone systems and methods according to embodiments of the invention.

#FIG. 2 is a block diagram of adaptive interference reducers according to embodiments of the present invention.

#FIG. 3 is a spectrum diagram that illustrates satellite L-band frequency allocations.

Detailed description6,317 words

#The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which typical embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.

#FIG. 1 is a schematic diagram of cellular satellite radiotelephone systems and methods according to embodiments of the invention. As shown in FIG. 1, these cellular satellite radiotelephone systems and methods 100 include at least one Space-Based Component (SBC) 110, such as a satellite. The space-based component 110 is configured to transmit wireless communications to a plurality of radiotelephones 120a, 120b in a satellite footprint comprising one or more satellite radiotelephone cells 130-130″″ over one or more satellite radiotelephone forward link (downlink) frequencies fD. The space-based component 110 is configured to receive wireless communications from, for example, a first radiotelephone 120a in the satellite radiotelephone cell 130 over a satellite radiotelephone return link (uplink) frequency fU. An ancillary terrestrial network, comprising at least one ancillary terrestrial component 140, which may include an antenna 140a and an electronics system 140b, is configured to receive wireless communications from, for example, a second radiotelephone 120b in the radiotelephone cell 130 over the satellite radiotelephone uplink frequency, denoted f′U, which may be the same as fU. Thus, as illustrated in FIG. 1, radiotelephone 120a may be communicating with the space-based component 110 while radiotelephone 120b may be communicating with the ancillary terrestrial component 140. As shown in FIG. 1, the space-based component 110 also undesirably receives the wireless communications from the second radiotelephone 120b in the satellite radiotelephone cell 130 over the satellite radiotelephone frequency f′U as interference. More specifically, a potential interference path is shown at 150. In this potential interference path 150, the return link signal of the second radiotelephone 120b at carrier frequency f′U interferes with satellite communications. This interference would generally be strongest when f′U=fU, because, in that case, the same return link frequency would be used for space-based component and ancillary terrestrial component communications over the same satellite radiotelephone cell, and no spatial discrimination between satellite radiotelephone cells would appear to exist.

#Still referring to FIG. 1, embodiments of satellite radiotelephone systems/methods 100 can include at least one gateway 160 that can include an antenna 160a and an electronics system 160b that can be connected to other networks 162 including terrestrial and/or other radiotelephone networks. The gateway 160 also communicates with the space-based component 110 over a satellite feeder link 112. The gateway 160 also communicates with the ancillary terrestrial component 140, generally over a terrestrial link 142.

Facts

Application

10/074,097Filed 12 Feb 2002 · us provisional application

Priority

14 Sep 2001

Published

US 2003/0054760 A120 Mar 2003

Granted

27 Jan 2004

Term ended

6 Sep 2022

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment, including 206 days of adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification8 codes

H04B 7/216
Multiple access: code division or spread-spectrum multiple access [CDMA, SSMA]
H04B 7/1853
Space-based or airborne stations; Stations for satellite systems: satellite systems for providing telephony service to a mobile station, i.e.…
H04B 7/18563
Satellite systems for providing telephony service to a mobile station, i.e. mobile satellite service: arrangements for interconnecting multiple…
H04B 7/18513
Systems using a satellite or space-based relay: transmission in a satellite or space-based system

Timeline

14 Sep 2001Priority claimedParent application 60/322,240
12 Feb 2002Application filedUS 10/074,097
12 Feb 2002Assigned to Mobile Satellite Ventures, LPassignment of assignor's interest
20 Mar 2003PublishedUS 2003/0054760 A1
27 Jan 2004GrantedUS 6,684,057 B2
17 Jun 2005Assigned to Atc Technologies, LLCassignment of assignor's interest
10 Apr 2006Assigned to The Bank of New Yorksecurity agreement
7 Oct 2010Assigned to Atc Technologies, LLC, Lightsquared LP, Lightsquared Finance Co.release of security interest
12 Oct 2010Assigned to Wilmington Trust Fsb, AS Collateral Trusteesecurity agreement
14 Jun 2011Assigned to Wilmington Trust Fsb, AS Collateral Trusteesecurity agreement
22 Jan 2016Assigned to Credit Suisse AG, Cayman Islands Branchsecurity agreement (first lien)
22 Jan 2016Assigned to Jefferies Finance LLCsecurity agreement (second lien)
11 Sep 2020Assigned to Jefferies Finance LLCsecurity interest
22 Oct 2020Assigned to Cortland Capital Market Services LLCassignment of security interest
26 Oct 2020Assigned to Atc Technologies, LLCrelease of security interest
26 Oct 2020Assigned to Ligado Networks LLC, Atc Technologies, LLCrelease of security interest
26 Oct 2020Assigned to U.S. Bank National Associationu.s. assignment of and amendment to intellectual property security agreement
30 Oct 2020Assigned to U.S. Bank National Association, AS Collateral Trusteesecond lien patent security agreement
30 Oct 2020Assigned to U.S. Bank National Association, AS Collateral Trusteefirst lien patent security agreement
6 Sep 2022Term endedEstimated, includes 206 days of adjustment
28 Dec 2022Assigned to U.S. Bank National Associationsecurity interest
3 Mar 2023Assigned to U.S. Bank Trust Company, National Association, AS Successor Collateral Agentu.s. assignment of and amendment to intellectual property security agreements
13 Dec 2024Assigned to U.S. Bank Trust Company, National Association, AS Successor Collateral Agentassignment of and amendment to intellectual property security agreements

Systems and methods for terrestrial reuse of cellular satellite frequency spectrum

Life of this patent

Systems and methods for terrestrial reuse of cellular satellite frequency spectrum

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims305

Description9,471 words

Drawings

Classification8 codes

Life of this patent

Description9,471 words