Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.73 Filed 07/20/22 Page 1 of 29
`
`Exhibit 2
`
`

`

`( 12 ) United States Patent
`Li et al .
`
`( 10 ) Patent No .: US 10,833,908 B2
`( 45 ) Date of Patent :
`* Nov . 10 , 2020
`
`US010833908B2
`
`( 72 )
`
`( 54 ) CHANNEL PROBING SIGNAL FOR A
`BROADBAND COMMUNICATION SYSTEM
`( 71 ) Applicant : NEO WIRELESS LLC , Wayne , PA
`( US )
`Inventors : Xiaodong Li , Kirkland , WA ( US ) ;
`Titus Lo , Bellevue , WA ( US ) ; Kemin
`Li , Bellevue , WA ( US ) ; Haiming
`Huang , Bellevue , WA ( US )
`( 73 ) Assignee : NEO WIRELESS LLC , Wayne , PA
`( US )
`Subject to any disclaimer , the term of this
`patent is extended or adjusted under 35
`U.S.C. 154 ( b ) by 0 days .
`This patent is subject to a terminal dis
`claimer .
`
`( * ) Notice :
`
`( 21 ) Appl . No .: 16 / 902,740
`( 22 )
`Jun . 16 , 2020
`
`Filed :
`
`( 65 )
`
`Prior Publication Data
`Oct. 1 , 2020
`US 2020/0313948 A1
`
`( 63 )
`
`Related U.S. Application Data
`Continuation of application No. 15 / 953,950 , filed on
`Apr. 16 , 2018 , now Pat . No. 10,771,302 , which is a
`( Continued )
`
`( 51 ) Int . Cl .
`H04L 12/26
`H04L 27/26
`
`( 52 ) U.S. CI .
`CPC
`
`( 2006.01 )
`( 2006.01 )
`( Continued )
`
`H04L 27/2626 ( 2013.01 ) ; H04B 1/707
`( 2013.01 ) ; H04B 1/711 ( 2013.01 ) ;
`( Continued )
`
`( 58 ) Field of Classification Search
`CPC ..... H04L 12/26 ; HO4L 5/0007 ; H04L 5/0028 ;
`H04L 25/03834 ; HO4L 27/0008 ; H04L
`27/0012
`( Continued )
`References Cited
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`
`( 56 )
`
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`
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`
`( Continued )
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`( Jun . 2004 ) .
`
`( Continued )
`Primary Examiner Dmitry Levitan
`( 74 ) Attorney , Agent , or Firm — Volpe Koenig
`( 57 )
`ABSTRACT
`In a broadband wireless communication system , a spread
`spectrum signal is intentionally overlapped with an OFDM
`signal , in a time domain , a frequency domain , or both . The
`OFDM signal , which inherently has a high spectral effi
`ciency , is used for carrying broadband data or control
`information . The spread spectrum signal , which is designed
`to have a high spread gain for overcoming severe interfer
`ence , is used for facilitating system functions such as initial
`random access , channel probing , or short messaging . Meth
`ods and techniques are devised to ensure that the mutual
`interference between the overlapped signals is minimized to
`( Continued )
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.74 Filed 07/20/22 Page 2 of 29
`
`Multi - Carrier Transmitter Signal Processing
`
`810
`
`Serial to
`Parallel
`( S / P )
`
`Parallel
`10 Serial
`
`S ( 1 )
`
`cyclic
`prefix
`
`Sítss
`
`Pulse
`shaping
`
`spreading
`attenuator
`Spread Spectrum Transmitter Signal Processing
`
`Tx power control
`
`820
`
`

`

`US 10,833,908 B2
`Page 2
`
`have insignificant impact on either signal and that both
`signals are detectable with expected performance by a
`receiver .
`
`30 Claims , 18 Drawing Sheets
`
`HO4L 27/2605
`370/208
`
`H04L 5/1453
`370/312
`
`7,123,934 B1
`7,149,239 B2
`7,161,985 B2
`7,161,987 B2
`7,218,666 B2
`7,260,054 B2
`7,274,652 B1
`7,317,931 B2
`7,342,974 B2
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`7,403,556 B2
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`
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`
`7,418,042 B2
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`7,548,506 B2
`7,555,268 B2
`7,567,624 B1
`7,646,747 B2
`7,693,032 B2
`7,724,720 B2
`7,738,437 B2
`7,864,725 B2
`7,873,009 B2
`7,907,592 B2
`8,009,660 B2
`8,089,887 B2
`8,094,611 B2
`8,102,832 B2
`8,363,691 B2
`8,428,009 B2
`8,432,891 B2
`8,767,522 B2
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`
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`1452326
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`2003/058881
`
`10/2003
`4/2006
`9/1997
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`4/2009
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`Related U.S. Application Data
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`( 51 ) Int . Ci .
`H04L 5/00
`H04L 25/03
`H04L 27/00
`H04B 1/707
`H04B 1/711
`H04L 25/02
`( 52 ) U.S. CI .
`H04L 5/0007 ( 2013.01 ) ; H04L 5/0028
`CPC
`( 2013.01 ) ; H04L 25/03834 ( 2013.01 ) ; H04L
`27/0008 ( 2013.01 ) ; H04L 27/0012 ( 2013.01 ) ;
`H04L 27/2602 ( 2013.01 ) ; H04L 27/2647
`( 2013.01 ) ; H04L 5/0016 ( 2013.01 ) ; H04L
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`
`HO4L 1/0002
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`
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`
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`
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`( 56 )
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.75 Filed 07/20/22 Page 3 of 29
`
`

`

`US 10,833,908 B2
`Page 3
`
`( 56 )
`
`References Cited
`OTHER PUBLICATIONS
`International Search Report and Written Opinion for International
`Application No. PCT / US05 / 01939 , dated Apr. 26 , 2005 , 7 pages .
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`* cited by examiner
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.76 Filed 07/20/22 Page 4 of 29
`
`

`

`U.S. Patent
`
`Nov. 10 , 2020
`
`Sheet 1 of 18
`
`US 10,833,908 B2
`
`( frequency )
`
`Channel
`
`
`
`Subcarriers for subchannel 3
`
`Subcarriers for subchannel 2
`
`Subcarriers for Subchannel 1
`
`3
`
`2
`
`1
`
`
`
`Silent subcarriers
`
`
`
`Pilot subcarriers
`
`S 1 2 3 2 2 3 1 2 1 3 2 1 0 2 1 3 5 3 2 p 3 2 1 3 p 2 10 13 S
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.77 Filed 07/20/22 Page 5 of 29
`
`

`

`U.S. Patent
`
`Nov. 10 , 2020
`
`Sheet 2 of 18
`
`US 10,833,908 B2
`
`n + 4
`
`no 3 w
`
`
`
`Time slots
`
`n + 2 FIG . 2
`
`nt1
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.78 Filed 07/20/22 Page 6 of 29
`
`sjeuueyoans
`
`

`

`U.S. Patent
`
`Nov. 10 , 2020
`
`Sheet 3 of 18
`
`US 10,833,908 B2
`
`timeslot 6
`
`timeslot # 5
`
`timeslot # 4
`
`SP2
`
`timeslot # 3
`
`timeslot # 2
`
`316
`
`312
`
`frame # + 1
`
`314
`
`subframe # 4
`
`subframe # 3
`
`subframe # 2
`
`310
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.79 Filed 07/20/22 Page 7 of 29
`
`Frame ( 20ms ) frame #i
`
`Subframe ( 5ms ) subframe # 1
`
`800 us
`
`timeslot # 1
`
`
`Period 1 * SP2 : Special Period 2
`* SP1 : Special
`
`SP1
`
`

`

`U.S. Patent
`
`Nov. 10 , 2020
`
`Sheet 4 of 18
`
`US 10,833,908 B2
`
`UL slot # 3 UL slot # 31
`
`#IT UL slot # 2
`
`UL slot # 21
`
`UL slot # 1
`
`
`
`Example Configuration 1 : Symmetric ( 3 DL slots , 3 UL slots )
`
`UL slot # 1
`
`SP2
`
`DL slot # 4
`
`UL slot # 1
`
`SP2
`
`DL slot # 5
`
`
`
`Example Configuration 2 : Asymmetric ( 4 DL slots , 2 UL slots )
`
`DL slot # 4
`
`
`
`Example Configuration 3 : Asymmetric ( 5 DL slots , 1 UL slots )
`
`subframe ( 5ms )
`
`DL slot # 3 DL sìot # 3
`
`DL slot # 3
`
`FIG . 4
`
`DL slot # 2 DL slot # 3 SP2
`
`DL slot # 1
`
`SP
`
`412
`
`DL slot # 2
`
`DL slot 1
`
`SP1
`
`DL slot # 41 DL slot # 2
`
`SP1
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.80 Filed 07/20/22 Page 8 of 29
`
`

`

`U.S. Patent
`
`Nov. 10 , 2020
`
`Sheet 5 of 18
`
`US 10,833,908 B2
`
`GP2
`
`GP2
`
`
`
`OFDM symbol # 8
`
`
`Period 1 * GP2 : Guard Period 2
`* GP1 : Guard
`
`512
`
`
`
`OFDM symbol # 2
`
`510
`
`
`
`Time Slot ( 800 us )
`
`
`
`tim eslot #i
`
`
`
`symbol # 1 OFDM symbol ( 100us ) OFDM
`
`
`
`
`
`
`
`Spread spectrum signal #j
`
`GP1
`
`
`
`not synchronized
`
`synchronized
`
`
`
`
`
`Spread spectrum signal #k
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.81 Filed 07/20/22 Page 9 of 29
`
`GP
`
`514
`
`

`

`U.S. Patent
`
`Nov. 10 , 2020
`
`Sheet 6 of 18
`
`US 10,833,908 B2
`
`MC signal
`
`SS signal
`
`S
`
`1
`
`FIG . 6
`
`s 1 2 3 2 2 3 1 2 1 3 2 1 2 1 3 5 3 2 2 3 2 1 3 p 21 p 13 s
`
`1
`
`Xoooo
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.82 Filed 07/20/22 Page 10 of 29
`
`

`

`U.S. Patent
`
`Nov. 10 , 2020
`
`Sheet 7 of 18
`
`US 10,833,908 B2
`
`MC signal
`
`SS signal
`
`
`
` WO * at 2W
`
`subchannel n
`
`* KBOX
`
`de tabak
`
`subchannel k
`
`FIG . 7
`
`subchannel i
`
`subchannel 1
`
`subchannel
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.83 Filed 07/20/22 Page 11 of 29
`
`

`

`U.S. Patent
`
`Nov. 10 , 2020
`
`Sheet 8 of 18
`
`US 10,833,908 B2
`
`810
`
`800
`
`s ( )
`
`G2
`
`830
`
`DIA
`
`
`
`Tx power control
`
`820
`
`S ( 1 ) MC
`
`H
`
`3 {
`
`3
`
`11
`
`3
`
`8
`
`1
`
`Parallel to Serial ( P / S )
`Add cyclic prefix
`
`IDFT
`Serial to Parallel ( S / P )
`
`FIG . 8
`
`m
`
`G4
`
`S ( t ) ss
`
`Pulse shaping
`
`Www
`
`
`
`
`Spread Spectrum Transmitter Signal Processing
`
`attenuator
`
`spreading
`
`
`
`
`
`
`
`Multi - Carrier Transmitter Signal Processing
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.84 Filed 07/20/22 Page 12 of 29
`
`1 11 FI 11 +
`
`1
`
`1
`
`3 3 1
`
`1
`
`i 1 1 1
`
`3 }
`
`8
`
`

`

`U.S. Patent
`
`Nov. 10 , 2020
`
`Sheet 9 of 18
`
`US 10,833,908 B2
`
`AGC
`
`920
`
`910
`
`900
`
`F
`
`$ 3
`
`3
`
`3 2 15
`
`7
`
`1
`
`2 5
`
`FIG . 9
`
`c * t )
`
`MC Synchronization Circuit
`
`Serial to Parallel ( S / P )
`Remove cyclic prefix
`
`Parallel to Serial ( P / S )
`
`Pre processing
`
`correlator
`
`Peak Detector
`Further Processing
`
`
`
`
`
`Multi - Carrier Receiver Processing
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.85 Filed 07/20/22 Page 13 of 29
`
`1
`
`1
`
`! 1
`
`5
`
`5 5
`
`5 1 1
`
`$
`
`5
`
`$
`
`$
`
`
`
`Spread Spectrum Receiver Processing
`
`
`
`
`
`

`

`U.S. Patent
`
`Nov. 10 , 2020
`
`Sheet 10 of 18
`
`US 10,833,908 B2
`
`1002
`
`K
`
`portal
`
`MS ;
`
`1004
`
`MC
`
`MC
`
`ISS
`
`?
`
`MS
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.86 Filed 07/20/22 Page 14 of 29
`
`

`

`U.S. Patent
`
`Nov. 10 , 2020
`
`Sheet 11 of 18
`
`US 10,833,908 B2
`
`BS
`
`BS ;
`
`MS in
`
`MC ,
`
`SS
`
`MC
`
`MC
`
`MS ;
`
`MS1
`
`1110
`
`FIG . 11 3
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.87 Filed 07/20/22 Page 15 of 29
`
`

`

`U.S. Patent
`
`Nov. 10 , 2020
`
`Sheet 12 of 18
`
`US 10,833,908 B2
`
`AGC
`
`X
`
`
`
`
`
`Cancelling the interfering SS signal
`
`1210
`
`1220
`
`1
`
`0
`
`5 2 5
`
`MC Synchronization Circuit
`
`Serial to Parallel ( S / P )
`Remove cyclic prefix
`
`Decision directed signal
`recovery
`
`
`
`
`
`Multi - Carrier Receiver Processing
`
`Parallel to Serial ( P / S )
`
`SS detection
`
`FIG . 12
`
`Pre processing
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.88 Filed 07/20/22 Page 16 of 29
`
`H
`
`5
`
`$ 3 $
`
`1
`
`.
`
`1
`
`H
`
`E
`
`{ 1 $ 3 $ 3
`
`

`

`U.S. Patent
`
`Nov. 10 , 2020
`
`Sheet 13 of 18
`
`US 10,833,908 B2
`
`( time )
`
`t
`
`1306
`
`1304
`
`1308
`
`
`
`
`
`Spread spectrum signal #p
`
`MC symbol ( or slot )
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.89 Filed 07/20/22 Page 17 of 29
`
`
`
`
`
`Spread spectrum signal #n
`
`1302
`
`FIG . 13
`
`
`
`
`
`Spread spectrum signal #m
`
`

`

`U.S. Patent
`
`Nov. 10 , 2020
`
`Sheet 14 of 18
`
`US 10,833,908 B2
`
`MC signal
`
`** CAR RWXQK
`
`SS signal
`
`
`
`** ** waWack
`
`
`
`
`
`eader ** SERIES NCPNEVAD ***
`
`DAR
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.90 Filed 07/20/22 Page 18 of 29
`
`FIG . 14
`
`subchannel n
`
`subchannel i
`
`subchannel 1
`
`subchannel k
`
`subchannel
`
`

`

`U.S. Patent
`
`Nov. 10 , 2020
`
`Sheet 15 of 18
`
`US 10,833,908 B2
`
`1502
`
`1506
`
`1504
`
`MC control signal
`
`!
`11
`11
`1
`
`1
`1
`
`***
`
`SS
`
`10MHZ ( ME
`
`1
`
`FIG . 15
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.91 Filed 07/20/22 Page 19 of 29
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`

`

`U.S. Patent
`
`Nov. 10 , 2020
`
`Sheet 16 of 18
`
`US 10,833,908 B2
`
`1506
`
`{
`
`3
`3
`3
`3
`
`1
`
`IOMHz ( MC )
`
`1 : 1
`
`1
`
`0
`
`5.68 or 7.68MHz ( SS )
`
`!
`
`1
`
`E
`&
`
`9
`.
`
`FIG . 16
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.92 Filed 07/20/22 Page 20 of 29
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`

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`U.S. Patent
`
`Nov. 10 , 2020
`
`Sheet 17 of 18
`
`US 10,833,908 B2
`
`1702
`
`BS
`
`MS
`
`preting STELLE
`
`SS
`
`SS
`
`MC ;
`
`MS
`
`1704
`
`MC jina
`
`MS1
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.93 Filed 07/20/22 Page 21 of 29
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`U.S. Patent
`
`Nov. 10 , 2020
`
`Sheet 18 of 18
`
`US 10,833,908 B2
`
`Frequency
`
`???
`
`1 (
`
`
`Channel Response in Frequency ( Frequency
`Selectivity )
`
`8
`
`12
`
`Time
`
`Channel Response in Time
`
`
`
`Max delay spread , Esmax
`
`?????
`
`X
`
`4 *
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.94 Filed 07/20/22 Page 22 of 29
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`US 10,833,908 B2
`
`5
`
`30
`
`1
`CHANNEL PROBING SIGNAL FOR A
`BROADBAND COMMUNICATION SYSTEM
`
`2
`FIG . 4 illustrates three examples of a subframe structure
`in the exemplary OFDM system .
`FIG . 5 illustrates slot structure of the OFDM system and
`the overlay system .
`CROSS - REFERENCE TO RELATED
`FIG . 6 is an illustration of MC signals overlaid with DSSS
`APPLICATION ( S )
`signals in the frequency domain where the power level of the
`DSSS signal is much lower than that of the MC signal .
`This application is a continuation of U.S. patent applica
`FIG . 7 is same as FIG . 6 wherein not all MC subchannels
`tion Ser . No. 15 / 953,950 , filed Apr. 16 , 2018 , which is
`are occupied .
`continuation of U.S. patent application Ser . No. 14 / 321,615 ,
`FIG . 8 illustrates a transmitter structure of MC and DSSS
`filed Jul . 1 , 2014 , which issued on Apr. 17 , 2018 as U.S. Pat . 10
`overlay system .
`No. 9,948,488 , which is a continuation application of U.S.
`FIG . 9 illustrates a receiver structure of MC and DSSS
`patent application Ser . No. 13 / 861,942 , filed Apr. 12 , 2013 ,
`overlay system .
`which issued on Jul . 1 , 2014 as U.S. Pat . No. 8,767,522 ,
`FIG . 10 illustrates examples of communications between
`which is a continuation application of U.S. patent applica
`tion Ser . No. 13 / 347,644 , filed Jan. 10 , 2012 , which issued 15 a base station and multiple mobile stations transmitting
`DSSS and MC signals .
`on Apr. 23 , 2013 as U.S. Pat . No. 8,428,009 , which is a
`FIG . 11 illustrates a mobile station sending DSSS signals
`continuation application of U.S. patent application Ser . No.
`12 / 975,226 , filed Dec. 21 , 2010 , which issued on Jan. 10 ,
`to its current serving base station , or other base stations .
`2012 as U.S. Pat . No. 8,094,611 , all of which are incorpo
`FIG . 12 illustrates using interference cancellation tech
`rated herein by reference . U.S. patent application Ser . No. 20 nique to cancel interfering DSSS signal in a composite
`12 / 975,226 is a continuation application of U.S. patent
`signal to obtain a clearer MC signal .
`FIG . 13 illustrates a DSSS signal and a MC signal fully
`application Ser . No. 10 / 583,229 , filed Aug. 27 , 2008 , which
`issued on Jan. 4 , 2011 as U.S. Pat . No. 7,864,725 , which is
`overlaid or partially overlaid at MC symbol or slot boundary
`the National Stage Application of International Application
`in time domain .
`No. PCT / US2005 / 003518 , filed Jan. 27 , 2005 , which claims 25
`FIG . 14 illustrates a DSSS signal with a high Peak to
`the benefit of U.S. Provisional Patent Application No.
`Average Ratio in frequency domain causing strong interfer
`60 / 540,586 , filed on Jan. 30 , 2004 , and of U.S. Provisional
`ence to certain MC subcarriers .
`Patent Application No. 60 / 540,032 , filed on Jan. 29 , 2004 .
`FIG . 15 illustrates using spectrum nulls in DSSS signal to
`protect an MC control subchannel .
`FIG . 16 illustrates spectrum control for DSSS signal using
`BACKGROUND
`simple sub - sampling method .
`FIG . 17 illustrates examples of communications between
`A direct Sequence Spread Spectrum ( DSSS ) system is
`a base station and multiple mobile stations transmitting both
`inherently capable of supporting multi - cell and multi - user
`access applications through the use of orthogonal spreading
`DSSS and MC signals .
`codes . The initial access of the physical channel and fre- 35
`FIG . 18 illustrates a typical channel response in the time
`quency planning are relatively easier because of interference
`and frequency domains . By estimating the peaks of a chan
`averaging in a DSSS system . It has been widely used in
`nel response in the time domain , the channel profile in the
`some existing wireless networks . However , a DSSS system
`frequency domain can be obtained .
`using orthogonal spreading codes , may suffer severely from
`the loss of orthogonally in a broadband environment due to 40
`DETAILED DESCRIPTION
`multi - path propagation effects , which results in low spectral
`efficiency .
`A broadband wireless communication system where both
`In broadband wireless communications , Multi - Carrier
`the Multi - Carrier ( MC ) and direct Sequence Spread Spec
`( MC ) technology is drawing more and more attention
`trum ( DSSS ) signals are intentionally overlaid together in
`because of its capability . An MC system such as an Orthogo- 45 both time and frequency domains is described . The system
`nal Frequency Division Multiplexing ( OFDM ) system is
`takes advantage of both MC and DSSS techniques to miti
`capable of supporting broadband applications with higher
`gate their weaknesses . The MC signal is used to carry
`spectral efficiency . An MC system mitigates the adverse
`broadband data signal for its high spectral efficiency , while
`effects of multi - path propagation in wireless environments
`the DSSS signal is used for special purpose processing , such
`by using cyclic prefixes to extend the signal period as the 50 as initial random access , channel probing , and short mes
`data is multiplexed on orthogonal sub - carriers . In effect , it
`saging , in which signal properties such as simplicity , self
`converts a frequency selective channel into a number of
`synchronization , and performance under severe interference
`parallel flat fading channels which can be easily equalized
`are of concern . In the embodiments of this invention both the
`with simple one - tap equalizers . The modulator and the
`MC and the DSSS signals are distinguishable in normal
`demodulator can be executed efficiently via the fast Fourier 55 operations and the interference between the overlaid signals
`transform ( FFT ) with much lower cost . However , MC is insufficient to degrade the expected performance of either
`systems are vulnerable while operating in multi - user and
`signal .
`Unlike a typical CDMA system where the signals are
`multi - cell environments .
`designed to be orthogonal in the code domain or an OFDM
`BRIEF DESCRIPTION OF THE DRAWINGS
`60 system where the signals are designed to be orthogonal in
`frequency domain , the embodiments of this invention over
`FIG . 1 illustrates a basic structure of a multi - carrier signal
`lay the MC signal , which is transmitted without or with very
`low spreading , and the DSSS signal , which is transmitted at
`in the frequency domain , made up of subcarriers .
`FIG . 2 illustrates a radio resource being divided into small
`a power level lower than that of the MC signal .
`units in both frequency and time domains .
`In accordance with aspects of certain embodiments of this
`FIG . 3 illustrates a frame structure of an exemplary
`invention , the MC signal is modulated on subcarriers in the
`frequency domain while the DSSS signal is modulated by
`OFDM system .
`
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`US 10,833,908 B2
`
`4
`( time slots ) . The basic structure of an MC signal in the time
`domain is made up of time slots to support multiple - access .
`AN EXEMPLARY MC SYSTEM
`
`30
`
`35
`
`Data Rate
`Modulation
`Coding rate
`IFFT / FFT size
`OFDM symbol duration
`Guard interval
`Subcarrier spacing
`System sampling rate ( fs )
`Channel spacing
`
`3
`the information bits or symbols in the time domain . In some
`cases the information bits modulating the DSSS sequence
`are always one .
`This invention further provides apparatus and means to
`implement the mentioned processes and methods in a broad- 5
`An OFDM system is used in the system as a special case
`band wireless multi - access and / or multi - cell network , using
`of an MC system . The system parameters for the uplink
`advanced techniques such as transmit power control , spread
`under consideration are listed in Table 1. FIG . 3 illustrates
`ing signal design , and iterative cancellation .
`a frame structure of a suitable OFDM system . In this system ,
`The mentioned MC system can be of any special format
`10 a 20 ms frame 310 is divided into four 5 ms subframes 312 .
`such as OFDM or Multi - Carrier Code Division Multiple
`One subframe 312 consists of six time slots 314 and two
`Access ( MC - CDMA ) . The presented methods and apparatus
`special periods 316 , which serve transition time from down
`can be applied to downlink , uplink , or both , where the
`link to uplink and vise versa . The six time slots in one
`duplexing technique can be either Time Division Duplexing
`subframe can be configured as either uplink or downlink
`( TDD ) or Frequency Division Duplexing ( FDD ) .
`15 slots symmetrically or asymmetrically .
`Various embodiments of the invention are described to
`FIG . 4 illustrates three examples of a subframe structure
`provide specific details for thorough understanding and
`in an OFDM system : one symmetric configuration 412 and
`enablement ; however , the aspects of the invention may be
`two asymmetric configurations 414 , each with differing
`practiced without such details . In some instances , well
`number of uplink ( UL ) and downlink ( DL ) slots . FIG . 5
`known structures and functions have not been shown or 20 illustrates a slot structure of an OFDM system and an
`described in detail to avoid unnecessarily obscuring the
`overlay system . One 800 us time slot 510 is comprised of 8
`OFDM symbols 512 , which are overlaid by DSSS signals
`essential matters .
`Unless the context clearly requires otherwise , throughout
`514 in the time domain . Two guard periods GP1 and GP2 are
`allocated for the DSSS signal 514 .
`the description and the claims , the words " comprise , " " com
`prising , ” and the like are to be construed in an inclusive 25
`sense as opposed to an exclusive or exhaustive sense ; that is
`to say , in the sense of “ including , but not limited to . ” Words
`using the singular or plural number also include the plural or
`singular number respectively . Additionally , the words
`“ herein , ” “ above , " " below ” and words of similar import ,
`when used in this application , shall refer to this application
`as a whole and not to any particular portions of this
`application . When the claims use the word “ or ” in reference
`to a list of two or more items , that word covers all of the
`following interpretations of the word : any of the items in the
`list , all of the items in the list and any combination of the
`items in the list .
`
`TABLE 1
`Uplink system parameters
`2 , 4 , 8 , 16 , 24 Mbps
`QPSK , 16 - QAM
`1/8 , 1/4 , 1/2 , 3/4
`1024
`100 us
`11.11 us
`9.765625 kHz
`11.52 MHz
`10 MHz
`
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`
`40
`
`DETAILED DESCRIPTION OF A MC AND DSSS
`MULTI - CARRIER COMMUNICATION SYSTEM
`OVERLAY SYSTEM
`The physical media resource ( e.g. , radio or cable ) in a
`FIG . 5 illustrates the overlay of the MC and DSSS signals ,
`where the DSSS signal overlaps with the MC signal in the
`multi - carrier communication system can be divided in both
`time domain . The overlaid signal can be aligned at the
`the frequency and time domains . This canonical division
`provides a high flexibility and fine granularity for resource 45 boundary of MC slot or MC symbol when they are synchro
`sharing
`nized ( for example , DSSS signal #k in FIG . 5 ) . It can also
`The basic structure of a multi - carrier signal in the fre
`be not aligned when they are not synchronized ( for example ,
`DSSS signal #j in FIG . 5 ) . In one embodiment , the DSSS
`quency domain is made up of subcarriers . Within a particular
`spectral band or channel , there are a fixed number of
`signal is placed at the period of cyclic prefix of the OFDM
`50 symbol .
`subcarriers . There are three types of subcarriers :
`FIG . 6 is an illustration of MC signals overlaid with DSSS
`1. Data subcarriers , which contain information data ;
`signals in the frequency domain where the power level of the
`2. Pilot subcarriers , whose phases and amplitudes are pre
`DSSS signal is much lower than that of the MC signal . The
`determined and made known to all receivers and which
`subcarriers in a subchannel are not necessarily adjacent to
`are employed for assisting system functions such as
`55 each other in the frequency domain . FIG . 7 is similar to FIG .
`estimation of system parameters ; and
`6 wherein not all MC subchannels are occupied . It illustrates
`3. Silent subcarriers , which have no energy and are used for
`a scenario where some MC subchannels are not energized .
`guard bands and DC carrier .
`In another embodiment , the MC signal is modulated on
`FIG . 1 illustrates a basic structure of a multi - carrier signal
`subcarriers in the frequency domain while the DSSS signal
`in the frequency domain , made up of subcarriers . The data 60 is modulated in either the time domain or the frequency
`subcarriers can be arranged into groups called subchannels
`domain . In one embodiment the modulation symbol on the
`to support scalability and multiple - access . The carriers
`DSSS sequence is one and the sequence is unmodulated .
`forming one subchannel are not necessarily adjacent to each
`FIG . 8 illustrates a transmitter structure 800 of an MC and
`other . As depicted in FIG . 1 , each user may use part or all
`DSSS overlay system , wherein the MC signal and DSSS
`65 signal are added together prior to Digital to Analog ( D / A )
`of the subchannels .
`FIG . 2 illustrates a radio resource being divided into small
`conversion 830. In FIG . 8 , the top branch 810 is an OFDM
`transmitter and the bottom branch 820 is the spread spec
`units in both frequency ( subchannels ) and time domains
`
`

`

`US 10,833,908 B2
`
`Case 2:22-cv-11408-TGB ECF No. 10-3, PageID.97 Filed 07/20/22 Page 25 of 29
`
`5
`6
`Denoting the received power of the MC signal as Pucand
`trum transmitter . In the MC transmitter , the S / P buffer
`the received power of the DSSS signal as Pss , the signal to
`converts the sequential inputs into parallel outputs , which
`interference and noise ratio ( SINR ) for the MC signal is :
`are in turn inputted to the inverse discrete Fourier transform
`( IDFT ) . The outputs from the IDFT are the time domain
`SINRMC = PM ( N + 1 )
`( 3 )
`signals , which are converted from parallel to sequential 5
`when the DSSS signal is not present ; and is
`signals after a cyclic prefix is added . Adding the prefix can
`also be performed after the P / S conversion . In the spread
`SINR'MC = Pud ( N + I + Pss )
`( 4 )
`spectrum transmitter , the DSSS sequence is modulated by
`when the DSSS signal is present . The system is designed
`the information bits or symbols and the modulated signals
`meets the SINR requirement for the
`such that the SINR ' ,
`will undergo pulse - shaping filtering so that the signal spec- 10
`MC
`MC signal and its performance is not compromised in spite
`trum meets specified criteria .
`of interference from the overlaid DSSS signal .
`A digital attenuator ( G1 ) is used for the DSSS signal to
`In one embodiment , the DSSS signal is power controlled
`adjust its transmitted signal level relative to the MC signal .
`such that Pss is well below the noise level , N.
`The two signals are overlaid in the digital domain before
`On the other hand , the SINR for the DSSS signal is
`converting to a composite analog signal . A second analog 15
`variable gain ( G2 ) is used subsequent to the D / A converter
`SINRSS = PSS / ( N + I + PMC )
`( 5 )
`830 to further control the power level of the transmitted
`Denoting the spreading factor for the DSSS signal as KSF ,
`signal . When the MC signal is not present , both G1 and G2
`the effective SINR for one symbol after despreading is :
`will be applied to the DSSS signal to provide sufficient
`* KSF ( N + I + PMC )
`transmission dynamic range . G2 can be realized in multiple 20
`SINR'ss = P ss
`( 6 )
`circuit stages .
`SINR'ss must be high enough to meet the performance
`FIG . 9 illustrates a receiver structure 900 of an MC and
`requirement when detecting or decoding the information
`DSSS overlay system . A composite signal is processed by a
`conveyed in the DSSS signal . In one embodiment , KSF is
`MC receiver 910 and DSSS receiver 920. At the receiver
`chosen to be 1000 , so that the DSSS signal is boosted with
`side , after automatic gain control ( AGC ) , an Analog - to- 25 30 dB spreading gain after despreading .
`Digital ( ND ) converter 930 converts the received analog
`FIG . 11 illustrates a mobile station 1110 sending DSSS
`signal to digital signal . The MC receiver basically performs
`signals to its current serving base station or other base
`a reverse process of the MC transmitter . The MC synchro
`stations . The latter case is especially helpful in hand - off
`nization circuit carries out the synchronization in both time
`processes . In this Figure , a mobile station MSK is commu
`and frequency for the receive