US6539003B1 — Method for acquisition and synchronization of ter…

Claim 1

Independent Claim 131 words

A time division multiple access wireless communications network having a fixed programmable transmission frame comprising: a communications terminal for communicating signals on bursts within the transmission frame, said terminal comprising burst time plan means for dynamically storing burst time plan information and for communicating signals on bursts based upon said time plan information; a network command controller for coordinating communications by said communication terminal, said network command controller being operative to maintain said transmit and receive time plans and further comprising means for dynamically changing the values of parameters of said bursts in said burst time plan means; and a reference terminal connected to said network controller for transmitting and receiving said signals on said bursts, wherein said bursts have parameters which may be dynamically changed by said network command controller.

Claim 2

Dependent Claim 131 words

A time division multiple access wireless communications network having a fixed programmable transmission frame comprising: a communications terminal for communicating signals on bursts within the transmission frame, said terminal comprising burst time plan means for dynamically storing burst time plan information and for communicating signals on bursts based upon said time plan information; a network command controller for coordinating communications by said communication terminal, said network command controller being operative to maintain said transmit and receive time plans and further comprising means for dynamically changing the values of parameters of said bursts in said burst time plan means; and a reference terminal connected to said network controller for transmitting and receiving said signals on said bursts, wherein said bursts have parameters which may be dynamically changed by said network command controller.

Claim 3

Dependent Claim 16 words

The network of claim 1 , wherein said parameters may be changed substantially in real time.

Claim 4

Dependent Claim 19 words

The network of claim 2 , wherein said parameters include one of length, frequency, or location within a frame.

Claim 5

Dependent Claim 109 words

A time division multiple access wireless communications network having a fixed programmable transmission frame comprising: a communications terminal for communicating signals on bursts within the transmission frame; a network command controller for coordinating communications by said communication terminal; and a reference terminal connected to said network controller for transmitting and receiving said signals on said bursts, wherein said bursts have parameters which may be dynamically changed by said network command controller, wherein said reference terminal transmits a reference burst to said communications terminal and said reference burst is used to derive network timing at said communications terminal and said reference burst may be located anywhere within the transmission frame.

Claim 6

Dependent Claim 109 words

A time division multiple access wireless communications network having a fixed programmable transmission frame comprising: a communications terminal for communicating signals on bursts within the transmission frame; a network command controller for coordinating communications by said communication terminal; and a reference terminal connected to said network controller for transmitting and receiving said signals on said bursts, wherein said bursts have parameters which may be dynamically changed by said network command controller, wherein said reference terminal transmits a reference burst to said communications terminal and said reference burst is used to derive network timing at said communications terminal and said reference burst may be located anywhere within the transmission frame.

Claim 7

Dependent Claim 15 words

The system of claim 4 , wherein the frame is a programmable, fixed period frame.

Claim 8

Dependent Claim 30 words

The system of claim 4 , wherein said communications terminal includes a local clock and generates a transmit frame period and receive frame period in response to said reference burst.

Claim 9

Dependent Claim 57 words

The system of claim 4 further comprising: a plurality of communications terminals, wherein said plurality of terminals are partitioned into control groups and said reference terminal transmits a separate reference burst to each control group, each said separate reference burst being transmitted on different carriers at a different frequency and not overlapping in time with each other.

Claim 10

Dependent Claim 48 words

The system of claim 7 , wherein said plurality of terminals include a local clock and generate a start of transmit frame period and receive of transmit frame period in response to said reference burst and said start of transmit frame period is identical across said different carriers.

Claim 11

Dependent Claim 22 words

The system of claim 4 , wherein said communications terminal determines a window of time in which to look for a burst.

Claim 12

Dependent Claim 51 words

The system of claim 9 , wherein said communications terminal generates a search window having a first guard time when said terminal is acquiring synchronization to said network system and generates a track window having a second guard time that is smaller that said first guard time once synchronization is acquired.

Claim 13

Dependent Claim 49 words

The system of claim 9 , wherein said reference burst a includes a unique word portion and said communication terminal search for said unique word in said aperture and detects said unique word if a unique word stored at said communication terminal matches unique word found in said aperture.

Claim 14

Dependent Claim 59 words

The system of claim 11 , wherein the maximum number of mismatches allowed for detecting a unique word is set as a first threshold or a second threshold and said first threshold is used during acquisition of system timing, said second threshold is used after acquisition has been established, where said first threshold is smaller than said second threshold.

Claim 15

Dependent Claim 37 words

The system of claim 4 , wherein the system uses first and second unique words, and said first unique word is used in a reference burst and said second unique word is used in all other bursts.

Claim 16

Dependent Claim 46 words

The system of claim 1 , wherein said bursts include a reference burst transmitted by said reference terminal and are received by said communications terminal carrying network management messages from said network command controller and are also used by all receiving terminals to derive frame timing.

Claim 17

Dependent Claim 39 words

The system of claim 1 , wherein said bursts include a signaling burst transmitted by said communications terminal and are used to carry network management messages from the communications terminal to said network command controller or said reference terminal.

Claim 18

Dependent Claim 36 words

The system of claim 1 , wherein said bursts include a traffic burst which are transmitted by said communications terminal and reference terminal and received by said communications terminal and reference terminal and carry traffic data.

Claim 19

Dependent Claim 35 words

The system of claim 1 , wherein said bursts include an acquisition burst used during transmit acquisition of communications terminal, said acquisition burst being transmitted by said communications terminal and received by said reference terminal.

Claim 20

Dependent Claim 20 words

The system of claim 1 , wherein said bursts include a control burst which maintains a traffic terminal transmit synchronization.

Claim 21

Independent Claim 109 words

A method for synchronization of a terminal in a TDMA communications system, comprising the steps of: generating a receive frame time at an arbitrary point in time; generating a search aperture; searching for a reference burst within said receive frame using said search aperture; at said terminal generating a transmit frame period and receive frame period based on finding said reference burst within said search aperture, maintaining a transmit burst plan and a receive burst plan, and adding all other bursts in said terminal's receive burst time plan to said receive frame, and varying the content of said transmit burst plan and receive burst plan under central network control.

Claim 22

Independent Claim 109 words

A method for synchronization of a terminal in a TDMA communications system, comprising the steps of: generating a receive frame time at an arbitrary point in time; generating a search aperture; searching for a reference burst within said receive frame using said search aperture; at said terminal generating a transmit frame period and receive frame period based on finding said reference burst within said search aperture, maintaining a transmit burst plan and a receive burst plan, and adding all other bursts in said terminal's receive burst time plan to said receive frame, and varying the content of said transmit burst plan and receive burst plan under central network control.

Claim 23

Dependent Claim 51 words

The method of claim 19 wherein the step of searching for said reference burst further comprises the steps of: searching for a unique word within said receive frame; and advancing said search aperture by a fraction of the frame time if said unique word is not found and repeating said search.

Claim 24

Dependent Claim 57 words

The method of claim 20 further comprises the steps of: adjusting said receive frame time based on said unique word if said unique word is found within said frame; and searching for said reference burst using a track aperture, wherein said track aperture is positioned at the expected position of said unique word of said reference burst.

Claim 25

Dependent Claim 80 words

The method of claim 21 further comprising the three steps of: searching for said unique word in the track aperture; determining if data being received in the reference burst is error free; and determining if a frame number in said reference burst is increments each frame, wherein if any of said three steps fail, said terminal adjusts the start of receive frame to begin after a falsely detected unique word and repeating the step of searching for a unique word.

Claim 26

Independent Claim 94 words

A method for acquisition of a terminal in a TDMA communications system including a network controller, comprising the steps of: picking an unused acquisition burst from a pool of acquisition bursts; transmitting and acquisition command from the controller to the terminal including the parameters for said picked acquisition burst; after receiving the acquisition command at the terminal, generating a transmit frame offset and transmit frame ID at the terminal; transmitting an acquisition response from the terminal to the controller, wherein said acquisition response includes the terminal's ID, transmission frame ID and current delay estimate.

Claim 27

Independent Claim 94 words

A method for acquisition of a terminal in a TDMA communications system including a network controller, comprising the steps of: picking an unused acquisition burst from a pool of acquisition bursts; transmitting and acquisition command from the controller to the terminal including the parameters for said picked acquisition burst; after receiving the acquisition command at the terminal, generating a transmit frame offset and transmit frame ID at the terminal; transmitting an acquisition response from the terminal to the controller, wherein said acquisition response includes the terminal's ID, transmission frame ID and current delay estimate.

Claim 28

Dependent Claim 69 words

The method of claim 23 further comprising the steps of: starting a timer at the terminal; receiving said acquisition response at the controller; and transmitting a synchronization command including a unique word error and transmission frame ID correction to the traffic terminal, wherein if said synchronization command is received by the terminal the terminal applies the transmission frame ID correction to its transmission frame ID and begins transmit synchronization.

Claim 29

Dependent Claim 28 words

The method of claim 24 , wherein if said terminal does not receive said synchronization command and said timer times out, the terminal waits for another acquisition command.

Claim 30

Dependent Claim 15 words

The method of claim 25 , wherein the terminal maintains synchronization by transmitting control bursts.

Claim 31

Dependent Claim 123 words

A time division multiple access wireless communications system comprising: a communications terminal for communicating signals on bursts within a TDMA frame; and a controller for coordinating communications by said terminal, wherein the terminal comprises: means for generating a receive frame time at an arbitrary point in time, means for generating a search aperture for a reference burst within said receive frame, means for generating a transmit frame period and receive frame period based on finding said reference burst within said search aperture, said frame periods being freely set with respect to said reference burst, and means for maintaining a transmit burst plan and a receive burst plan, and adding all other bursts in said terminal's receive burst time plan to said receive frame.

Claim 32

Dependent Claim 123 words

A time division multiple access wireless communications system comprising: a communications terminal for communicating signals on bursts within a TDMA frame; and a controller for coordinating communications by said terminal, wherein the terminal comprises: means for generating a receive frame time at an arbitrary point in time, means for generating a search aperture for a reference burst within said receive frame, means for generating a transmit frame period and receive frame period based on finding said reference burst within said search aperture, said frame periods being freely set with respect to said reference burst, and means for maintaining a transmit burst plan and a receive burst plan, and adding all other bursts in said terminal's receive burst time plan to said receive frame.

Claim 33

Dependent Claim 40 words

The system of claim 27 wherein said terminal searches for a unique word within said receive frame and advances said search aperture by a fraction of the frame time if said unique word is not found and repeating the search.

Claim 34

Dependent Claim 54 words

The system of claim 28 wherein said terminal adjusts said receive frame time based on said unique word if said unique word is found within said frame and searches for said reference burst using a track aperture, said track aperture being positioned at the expected position of said unique word of said reference burst.

Claim 35

Dependent Claim 78 words

The system of claim 29 wherein said terminal searches for said unique word in the track aperture and determines if data being received in the reference burst is error free and if a frame number in said reference burst is incremented in each frame, whereby if any of said three steps fails, said terminal adjusts the start of receive frame to begin after a falsely detected unique word and repeats the step of searching for a unique word.

Claim 36

Dependent Claim 110 words

A time division multiple access wireless communications system comprising: a communications terminal for communicating signals on bursts within a TDMA frame; and a controller for coordinating communications by said terminal, wherein said controller picks an unused acquisition burst from a pool of acquisition bursts and transmits an acquisition command from said controller to said terminal including the parameters for said picked acquisition burst and after receiving said acquisition command at said terminal, generating a transmit frame offset and transmit frame ID at the terminal and transmitting an acquisition response from said terminal to said controller, whereby said acquisition response includes the terminal's ID, transmission frame ID and current delay estimate.

Claim 37

Dependent Claim 110 words

A time division multiple access wireless communications system comprising: a communications terminal for communicating signals on bursts within a TDMA frame; and a controller for coordinating communications by said terminal, wherein said controller picks an unused acquisition burst from a pool of acquisition bursts and transmits an acquisition command from said controller to said terminal including the parameters for said picked acquisition burst and after receiving said acquisition command at said terminal, generating a transmit frame offset and transmit frame ID at the terminal and transmitting an acquisition response from said terminal to said controller, whereby said acquisition response includes the terminal's ID, transmission frame ID and current delay estimate.

Claim 38

Dependent Claim 21 words

The system of claim 31 wherein said terminal includes a timer and said timer is started after sending said acquisition response.

Claim 39

Dependent Claim 58 words

The system of claim 32 wherein said control receives said acquisition response and transmits a synchronization command including a unique word error and transmission frame ID correction to the traffic terminal, whereby if said synchronization command is received by the terminal the terminal applies the transmission frame ID correction to its transmission frame ID and begins transmit synchronization.

Claim 40

Dependent Claim 28 words

The system of claim 33 , wherein if said terminal does not receive said synchronization command said timer times out and said terminal waits for another acquisition command.

Claim 41

Dependent Claim 18 words

The system of claim 33 , wherein said terminal maintains synchronization by transmitting control bursts to said controller.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2006-03-24	2006-09-23	2007-03-25	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2010-03-24	2010-09-23	2011-03-25	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2014-03-24	2014-09-23	2015-03-25	$7700.00	Window Closed / Lapsed

Method for acquisition and synchronization of terminals in a satellite/wireless TDMA system

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