US 20070058595Al
`
`(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2007/0058595 A1
`Classon et al.
`(43) Pub. Date:
`Mar. 15, 2007
`
`(54) NIETHOD AND APPARATUS FOR
`REDUCING ROUND TRIP LATENCY AND
`OVERHEAD WITHIN A COMMUNICATION
`SYSTEM
`
`App]. No;
`
`11/276,981
`
`Filed:
`
`Mar. 20, 2006
`
`Related U.S. Application Data
`
`Inventors: Brian K. Classon, Palatine, IL (US);
`Kevin L_ Baum, Roping Meadows, IL
`(US); Amitava Ghosh, Buffalo Grove,
`IL (US); Robert T. Love, Barrington,
`IL (1 IS); Vi]-ay Nangia, Algonquin: IL
`(US); Kenneth A. Stewart, Grayslake,
`IL
`S
`(U)
`Correspondence Address:
`MOTOROLA. INC.
`1303 EAST ALGONQUIN ROAD
`IL01/3RD
`
`SCHAUMBURG’ [L 60196
`
`Provisional application No. 60/666,494, filed on Mar.
`30a 2005
`
`_
`_
`.
`_
`Publication Classification
`
`Int.Cl.
`(2006.01)
`H04B 7/212
`U.S. Cl.
`.......................................... .. 370/337; 709/236
`
`ABSTRACT
`
`.
`
`(57)
`
`During operation radio frames are divided into a plurality of
`subframes. Data is transmitted over the radio frames Within
`
`(73) Assjgnee: MOTOROLA,
`(Us)
`
`INC” Schaumburgi
`
`IL
`
`a plurality of subframes, and having a frame duration
`selected from two or more possible frame durations.
`
`SCHEDULABLE
`
`SHORT FRAME MULIIPLEX
`
`”"“- -- IIIIIIIIIIII
`
`as
`
`/V‘IIIIIIII”‘IIIIIIII”‘II|IIIII
`0.5ms
`0.5ms
`
`A
`
`A
`
`SHORT FRAME
`(0.5ms)
`
`COMMON PILOT
`E CONTROL
`III DATA
`
`ZTE/SAMSUNG 1020-0001
`
`ZTE/SAMSUNG 1020-0001
`
`1
`
`APPLE 1020
`
`

`

`Patent Application Publication Mar. 15, 2007 Sheet 1 of 19
`
`US 2007/0058595 A1
`
`FIG. 1
`
`£0
`
`TRANSMITTER
`
`RECEIVER
`
`2
`
`ZTE/SAMSUNG 1020-0002
`
`ZTE/SAMSUNG 1020-0002
`
`2
`
`

`

`Patent Application Publication Mar. 15, 2007 Sheet 2 of 19
`
`US 2007/0058595 A1
`
`.301
`
`RADIO FRAME (10ms)
`
`
`
`/
`
`
`
`Tsf
`
`/
`/ SUB—FRAME
`P OFDM SYMBOLS
`
`Nrf SUB—FRAMES
`
`\
`
`\
`
`\
`
`Tsn
`
`Tsf
`
`FIG. 3
`300
`_
`
`SYMBOLS
`
`SCHEDULABLE
`
`
`05"“
`SHORT FRAME MULTIPLEX
`
`
`
`
`/”‘IIIIIIII”‘IIIIIIIIIIIIIIIIZN5
`
`\\\\\\////
`
`
`O.5ms
`O.5ms
`O.5ms
`
`
`SHORT FRAME
`(O.5ms)
`
`
`
`
`COMMON PILOT
`E CONTROL
`El DATA
`
`FIG. 4
`
`3
`
`ZTE/SAMSUNG 1020-0003
`
`ZTE/SAMSUNG 1020-0003
`
`3
`
`

`

`Patent Application Publication Mar. 15, 2007 Sheet 3 of 19
`
`US 2007/0058595 A1
`
`SCHEDULABLE
`UNIT \
`
`.
`
`LONG FRAME MULTIPLEX
`
`
`
`7/////. 7////..7/////.V//////
`
`
`
`
`
`7///////4
`
`
`
` 7/////A|%7////% 7/////AV//////u.7/////A
`
`
`
`
`
`?////é
`
`
`
`7//////.7/////J
`
`WV/////A%7////é
`
`
`
` V//////.7/////.7/////.Zr/////éI7////é
`
`
`
`V/////%|Z%
`
`V//////4
`
`
`
` 7/////.7//////.7/////A
`
`
`
`O.5ms
`
`O.5ms
`LONG
`
`V////%
`
`7//////
`
`v//////4I
`
`
`
`7//////H7//////
`
`7////éI
`
`
`
` 7//////.7//////.%
`
`0.5ms
`
`(Bms)
`
`O.5ms
`
`O.5ms
`
`|:|coMuoN PILOT SYMBOL
`
`E CONTROL SYMBOL
`
`DATA SYMBOL
`
`FIG. 5
`
`PARAMETER
`
`..r_MAnRFGN0I.
`
`N0T.TAnRUGIFN0C
`
`R
`
`S
`
`ADIO FRAME DURATION
`SUBFRAMES / RADIO FRAME
`SUBFRAME DURATION ms
`UBFRAMES / LONG FRAM
`LONG FRAME DURATION ms
`OVERHEED SUBFRAMES
`MAX LONG I RADIO FRAME
`
`E
`
`6 EXEMPLARY LONG FRAME CONFIGURATIONS vs. SUBFRAME DURATION
`
`ZTE/SAMSU NG 1020-0004
`
`ZTE/SAMSUNG 1020-0004
`
`4
`
`
`
`
`
`
`
`
`

`

`Patent Application Publication Mar. 15, 2007 Sheet 4 of 19
`
`US 2007/0058595 A1
`
`70,701
`
`702RADIO FRAME CONSTRUCIED FROM SHORT FRAMES
`
`|||||||||||l '|||||||||||l!
`\\
`
`SHORTRAMES Z
`
`4‘
`
`
`
`.
`RADIO FRAME n-1 E RADIO FRAME n E RADIO FRAME n+1
`CONTROL REGION /
`(
`) K
`
`
`LONG FRAME
`
`/’
`
`RADIO FRAME
`
`10ms \
`
`RADIO FRAME CONSTRUCTED FROM LONG FRAMES
`
`‘\
`
`
`
`
`SYNCHRONISATION
`
`D
`
`\
`
`,_
`
`703
`
`E CONTROL SYMBOL
`
`FIG. 7
`
`RADIO FRAME n-1 RADIO FRAME n I RADIO FRAME n+1
`
`/
`
`/
`
`\
`
`\
`
`\ \ \
`RADIO FRAME (10ms)
`/ , /
`RADIO FRAME GONSTRUGTED FROM LONG FRAMES \ ‘\
`
`/ /
`
`/ S
`
`IIII IIII IIII IIII
`SHORTRAMES
`LONG FRAME
`
`OR
`
`RADIO FRAME GONSIRUGIED FROM LONG FRAMES
`
`IIII
`HORTRAMES
`
`IIII
`LONG FRAME
`
`IIII
`
`EGONTROL SYMBOL
`
`SHORT FRAMES
`
`|:|
`
`LONG FRAMES
`
`.]E7T1FlCZ3F.
`
`£5?
`
`5
`
`ZTE/SAMSUNG 1020-0005
`
`ZTE/SAMSUNG 1020-0005
`
`5
`
`

`

`Patent Application Publication Mar. 15, 2007 Sheet 5 of 19
`
`US 2007/0058595 A1
`
`CYCLIC
`PR;g1IX
`
`NORMAL SUB-FRAME
`10 OFDM SYMBOLS
`
` | PAYLOAD
`
`
`
`
`/
`
`50.56;Ls<4)
`44.44,u.s
`
`50.0}ls
`
`0.5ms
`
`FIG 9
`
`9_00
`
`BROADCAST SUB-FRAME
`
`CYCLIC
`PREFIX
`
`9 OFDM SYMBOLS
`5’ ’ ‘ 5 ’ 0 IIIIIIII
`
`
`
`I44.44s
`55-55148
`
`0.5ms
`
`FIG. 10
`
`1000
`
`6
`
`ZTE/SAMSUNG 1020-0006
`
`ZTE/SAMSUNG 1020-0006
`
`6
`
`

`

`Patent Application Publication Mar. 15, 2007 Sheet 6 of 19
`
`US 2007/0058595 A1
`
`PARAMETER
`
`SUBFRAME CONFIGURATION
`
`AURs
`DH
`A0R:1Fr
`DRml3WW.
`UA
`RD
`SUBFRAME DURATION ms
`
`1WEMANROFnoAI
`
`Jmjjmj
`
`02
`
`V7
`.%J%i%
`IE—7 AME
`SUBCARRIER SPACING kHz mm 22.5
`4
`SYMBOL nunmou us
`55.5556 45.45
`us
`USEFUL
`44.44 44.44 A 44.4
`7
` flEZfi%
`SYMBOLS PER SUBFRAME E37 4
`TABLE 2 — EXEMPLARY SUBFRAME CONFIGURATIONS vs. THE NUMBER or OFDM
`SYMBOLS PER SUBFRAME AND SUBFRAME DURATION.
`
`54A
`
`PARAMETER
`
`SUBFRAME CONFIGURATION
`
`FIG- 11
`
`RADIO FRAME DURATION
`UBFRANES / RADIO FRAME
`UBFRAME DURATION ms
`UBCARRIER SPACING kHz
`SYMBOL DURATION us
`USEFUL
`
` S S
`
`us
`
`SYMBOLS PER SUBFRAME
`
`TABLE 3 — FURTHER EXEMPLARY SUBFRAME CONFIGURATIONS vs. THE NUMBER OF
`OFDM SYMBOLS PER SUBFRAME AND SUBFRAME DURATION
`
`ZTE/SAMSU NG 1020-0007
`
`ZTE/SAMSUNG 1020-0007
`
`7
`
`
`
`

`

`Patent Application Publication Mar. 15, 2007 Sheet 7 of 19
`
`US 2007/0058595 A1
`
`NORMAL SUB—FRAME
`
` LONG FRAME
`
`\
`
`5D.Ou§
`
`BROADCAST SUB—FRAME
`
`-
`
`\
`
`
`
`-----I ------
`EXAMPLE: 1/3 RADIO FRAME ALLOCATED TO BROADCAST
`
`EXAMPLE: 2/3 RADIO FRAME ALLOCATED TO BROADCAST
`
`’||||||||||
`
`0 EXAMPLE: ENTIRE RADIO FRAME ALLOCATED TO BROADCAST’ A
`\\
`_
`\
`/
`
`
`
`
`
`RADIO FRAME n
`
`RADIO FRAME n+1
`
`- --
`
`RADIO FRAME n—1
`
`BROADCAST FRAME
`
`|:| UNICAST FRAME
`
` SYNCHRONIZATION AND CONTROL REGION
`
`FIG. 12
`
`8
`
`ZTE/SAMSUNG 1020-0008
`
`ZTE/SAMSUNG 1020-0008
`
`8
`
`

`

`Patent Application Publication Mar. 15, 2007 Sheet 8 of 19
`
`US 2007/0058595 A1
`
`NORMAL SUB-FRAME
`
`\
`
`\
`
`5
`
`0.0u§
`/
`
`BROADCAST SUB-FRAME
`
`
`
`E--7%--I --7%.-I I-%---
`
`
`
`%-%-%-
`
`%-%-%-
`
`RADIO FRAME n-1
`
`RADIO FRAME n
`
`RADIO FRAME n+1
`
`- - -
`
`BROADCAST FRAME
`
`|:| UNICAST FRAME
`
` SYNCHRONIZATION AND CONTROL REGION
`
`FIG. 13
`
`9
`
`ZTE/SAMSUNG 1020-0009
`
`ZTE/SAMSUNG 1020-0009
`
`9
`
`

`

`Patent Application Publication Mar. 15, 2007 Sheet 9 of 19
`
`US 2007/0058595 A1
`
`RADIO FRAME CONSTRUCTED FROM SHORT & LONG FRAMES
`
`\\\\u\\\\\\\
`
`\\F\\\\\\\\\
`\\\\\\\\\\\\\
`\\\\u\\\\\\
`\\\\\\\\\\\\
`\\\\\\\\\\\\\
`\\\\\\\\\\\\
`\\\\u\\\\\\
`
`\\\\\\\\\\\\\
`\\\\\\m\\\\
`\\\\\\\\\\\\\
`l\\\\\\\\\\\\
`\\\\\\\\\\\\\
`\\\\\\\\u\\\
`\\\\\\m\\\\
`\\\\\\\\u\\\
`
`\\\x\\\\\\\\\
`\\\\\u\\\\\\
`\\\\\\\\\\\\\
`\\\\\\\\\\\\\
`\\\\\\\\\\\\\
`\\\\\m \\
`
`\\\\\u\\
`\\\\\m\\\\\
`
`
`
`
`
`
`\\\\\\\\u\\\
`\\\\\\\\\\\\\
`\\\\\\\\\\\\\
`\\\\\\\\\\\\\
`\\\\\\\\\\\\\
`\\\\\\\\u\\\
`\\\\\\\\\\\\\
`\\\\\\\\\\\\\
`
`_
`
`\\u\\\\\\\\
`\\\\\\\u\\\
`\\M\\\\\\\\
`\\\\\\\u\\\
`\\\\\\\\\\\\
`\\\\\\\\\\\\
`\\m\\\\\\\
`\\\\\\\\\\\\
`\\H\\\\\\\\
`\\\\\\\H\\\
`\\u\\\\\\\\
`\\\\\\\m\\
`\\u\\\\\\\\
`\\\\\\\u\\\
`\\u\\\\\\\\
`\\\\\\\m\\
`‘*1?’
`
`
`
`LONG FRAME
`
`
`
`FIG- 14
`
`
`
`msnom FRAMES
`|:|LoMc FRAME
`ESYMCHRDMIZAFIDM AND CONTROL REGION
`|:|suD—FRAME
`CELL SYNCHRONIZATION SYMBOL
`iGLOBAL SYNCHRONIZATION SYMBOL
`COMMON PILOT
`
`
`
`CONTROL
`DAFA
`PCH — PAGING CHANNEL INFORMATION
`BCCH — BROADCAST CONTROL CHANNEL INFO
`I]]]]]]]PI — PAGING INDICATORS
`AI — ACKNOWLEDGEMENT INDICATORS
`E01 - OTHER INDICATORS (NOT SPECIFIED)
`BI - BROADCAST INDICATORS
`
`10
`
`ZTE/SAMSUNG 1020-0010
`
`ZTE/SAMSUNG 1020-0010
`
`10
`
`

`

`Patent Application Publication Mar. 15, 2007 Sheet 10 of 19
`
`US 2007/0058595 A1
`
`R
`\\\\\\\\\\\\
`\\\\R\\\R\\\
`\A\A\\\\\\\\
`\A\\\\\\R\\\
`\\\\\\\\\\\\
`\\\\R\\\R\\\
`\A\A\\\\\\\\
`
`\ \
`\\\\\\\\\\\\\
`\\\\\\\\\\\\\
`\\\\\\\\\\\\A
`\\\\\\\\\\\\\
`\\\m\\\u\\
`\\\\\\\\\\\\\
`\\\\\\\\\\\\A
`
`LONG FRAME
`
`
`
`SYNCHRONIZATION
`AND coRRRoL
`REc1oR (EVERY
`jth RADIO ERAAAE)
`
`
`
`
`
`RADIO FRAME i CONSTRUCTED FROM SHORT & LONG FRAMES
`$51.11
`”§§§E§§
`R
`2
`\\\\\\\\\\\\ R\\\\\\\\\\R
`lIIll""
`\\\\\\\A\\\\ R\\\A\\\\\\R
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`\\A\\\\ R\\\A\A\\\\\
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`\\\\\\\\\\\\
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`\\\\\\\A\\\\ R\\\\\A\A\\\
`
`
`
`_‘
`
`
`
`\x‘\\\
`RR R
`/.
`
`
`
`V \
`
`05m
`RARE
`
`
`
`
`
`R
`
`
`
`\ \
`\
`R
`A\\\\\\R\\\\\ \\\\\\\\\\\\\
`\\\\\\\\\\\\\ \\\\\\\\\\\\\
`A\A\\\\\\\\\\ \\\\\\\\u\\\
`A\\\\\\\\\\\\ \\\\\\\\\\\\\
`A\\\\\\\\\\\\ \\\\\\\\u\\\
`\\\\\\\\\\\\\ \\\\\\\\\\\\\
`A\A\\\\\\\\\\ \\\\\\\\u\\\
`
`
`
`05m
`RRERRRRE
`
`
`\ \
`\
`\\\\\\\\\\\\\ \\\\\\\\\\\\\
`\\\\\\\\\\\\\ \\\\\\\\\\\\\
`\A\\\\\\\\\\\ \\\\\\\\\\m
`\A\\\\\\\\\\\ \\\\\\\\\\\\\
`\\\\\m\\\u \\\\\\\\\\\\\
`\\\\\\\\\\\\\ \\\\\\\\\\\\\
`\A\\\\\\\\\\\
`\\\A\\\\\\\\\
`
`"_
`
`
`
`RADIO FRAME i+1
`
`
`
`
`
`
`
`
`
`msnom FRAMES §sRRcRRoR1zARIoR AND CONTROL REGION
`|:|LoRc FRAME
`|:ISUB-FRAME
`CELL SYNCHRONIZATION SYMBOL
`GLOBAL SYNCHRONIZATION SYMBOL
`
`COMMON PILOT
`CONTROL
`
`PCH — PAGING CHANNEL INFORMATION
`BCCH - BROADCAST CONTROL CHANNEL INFO
`
`
`||]]]]]]P1 — PAGING INDICATORS
`AI — ACKNOWLEDGEMENT INDICATORS
`E01 - OTHER INDICATORS (NOT SPECIFIED)
`BI — BROADCAST INDICATORS
`
`
`11
`
`ZTE/SAMSUNG 1020-0011
`
`ZTE/SAMSUNG 1020-0011
`
`11
`
`

`

`Patent Application Publication Mar. 15, 2007 Sheet 11 of 19
`
`US 2007/0058595 A1
`
`SUPER FRAME i—1
`’
`
`SUPER FRAME i
`
`SUPER FRAME i+1
`“I
`
`RADIO FRAME:
`SYNCHRQNIZATION AND
`CONTROL REGION
`
`
`
`RADIO FRAME n—1
`
`RADIO FRAME n
`5:24:<
`
`RADIO FRAME 0
`
`
`
` \
`
`F
`
`/ RADIO FRAME (IOms) \
`RADIO FRAME CONSIRUCTED FROM SHORT AND LONG FRAMES \
`F
`F
`F
`\
`F
`F
`F
`F
`V‘
`F
`FF
`F
`\\\w\\\\
`\\\\A\\\w.
`\wA\\\vA\
`\\m\\\m\\
`\\\\A\\\\>A
`\m\\
`\\\m\\\
`\\\\vA\\w.
`\\\\\A\\\\u\ mxmmu
`uxuu \x\\\\VA\\\
`\\\\\I\\\\\
`\M\\\l\\\\\\
`\AA\\\\A\\\\
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`\\\\\\\\\\\
`vmuvmu
`\\v\\\\\\\\\
`\\v\\\m\\
`“Am F
`\\MvA\v.\A
`\\\\\\\\\\M\\ M\\\\\vuv.\
`\\\\A\I\\W\
`\\l\\\\\\\\\\
`\\\\\\\\\\\A
`\A\‘fl\\V\:\\ vxxvm F
`v
`SHORT FRAMES
`
`LONG FRAME
`
`FIG- 16
`
`MSHORT FRAMES
`|:|LONc FRAME
`ESYNOHRONIZAHON AND CONTROL REGION
`I:ISUB-FRAME
`SUPER FRAME CONTROL REGION
`SUPER FRAME k
`
`
`
`12
`
`ZTE/SAMSUNG 1020-D012
`
`--
`
`suPER FRAME
`
`ZTE/SAMSUNG 1020-0012
`
`12
`
`

`

`Patent Application Publication Mar. 15, 2007 Sheet 12 of 19
`
`US 2007/0058595 A1
`
`SUPER FRAME i-1
`//
`
`SUPER FRAME i
`
`SUPER FRAME i+1
`‘~
`
`RADIO FRAME:
`SYNCHRONIZATION AND
`CONTROL REGION
`
`F
`
`
`
`//
`RADIO FRAME O
`
`
`
`--
`
`su|=ER FRAME;
`CONTROL REGION
`
`/ RADIO FRAME (IOms)
`
`‘\
`
`K
`X
`RADIO FRAME GONSTRUCTED FROM SHORT AND LONG FRAMES\\
`
`
`
`FIG_ 1 7
`
`[33]sHoRI FRAMES
`|:|LoNc FRAME
`ESYNCHRONIZATION AND CONTROL REGION
`|:|SUB—FRAME
`SUPER FRAME CONTROL REGION
`
`
`13
`
`ZTE/SAMSUNG 1020-0013
`
`ZTE/SAMSUNG 1020-0013
`
`13
`
`

`

`Patent Application Publication Mar. 15, 2007 Sheet 13 of 19
`
`US 2007/0058595 A1
`
`I-
`SYNCHRONIZATION
`>.2= r:c2—u2o,_
`REGION
`
`RADIO FRAME CONSTRUCTED FROM SHORT & LONG FRAMES
`
`
`
`
`
`
`
`
`
`_
`
`05ms
`
`
`
`
`
`
`
`E‘
`
`
`
`
`7
`§§Z§m§§§§ fii
`\\
`\\A
`
`
`
`
`
`
`
`
`F’
`\\\\\\\\\\\\\
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`A
`
`
`\u\\\\\\\\\
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`\
`
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`
`\\\\\\\\\\\\\ \\\\\\\\\\\\\
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`A
`
`
`
`
`Long FRAME
`\\\\\\\\\\\\\
`\\\\\\\\\\\\\
`\\\\\\\\\\\\\
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`/
`
`
`
`/
`
`SHORT FRAMES
`
`\\\\\\\
`.*.
`\\\\
`\\\\\\
`\
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`\\\\\\\\\\\\
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`
`UL
`
`FR
`
`OFFSET
`
`RACH
`
`,/
`
`\
`
`
`
`ONE DOWNLINK AND UPLINK RADIO FRAME STRUCTURE
`
`FIG- 18
`
`RACH
`lzflsnom FRAMES
`
`COMMON PILOT
`|:|LoNc FRAME
`ESYNCHRONIZATION AND CONTROL REGION CONTROL
`I:ISUB—FRAME
`om
`SUPER FRAME CONTROL REGION
`SUPER FRAME k
`
`
`14
`
`ZTE/SAMSUNG 1020-0014
`
`ZTE/SAMSUNG 1020-0014
`
`14
`
`

`

`Patent Application Publication Mar. 15, 2007 Sheet 14 of 19
`
`US 2007/0058595 A1
`
`
`
`\
`\\\\\\\\\\\\
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`
`
`
`
`
`
`
`,1
`
`
`
` \
`
`RADIO FRAME CONSTRUCTED FROM SHORT & LONG FRAMES
`l<
`SYNCHRONIZATION
`
`
`AND CONTROL
`REGION
`%§§_§R§R§§?R§R§§§§§Z§R
`\\\\
`
`
`
`
`LONG RACH LONG FRAME
`EVERY 100ms OTHERWISE
`DATA LONG FRAME
`
`SHORT RACH
`
`ALTERNATIVE UPLINK FRAME sTRucTuRE
`
`RACH
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`
`15
`
`ZTE/SAMSUNG 1020-0015
`
`ZTE/SAMSUNG 1020-0015
`
`15
`
`

`

`Patent Application Publication Mar. 15, 2007 Sheet 15 of 19
`
`US 2007/0058595 Al
`
`
`
`_
`05ms
`
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`
`RADIO FRAME CONSTRUCTED FROM SHORT & LONG FRAMES
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`16
`
`ZTE/SAMSUNG 1020-0016
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`16
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`

`

`Patent Application Publication Mar. 15, 2007 Sheet 16 of 19
`
`US 2007/0058595 A1
`
`I-
`STNCHRONIZATION
`AND CONTROL
`
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`RADIO FRAME CONSTRUCTED FROM SHORT & LONG FRAMES
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`
`17
`
`ZTE/SAMSUNG 1020-0017
`
`ZTE/SAMSUNG 1020-0017
`
`17
`
`

`

`Patent Application Publication Mar. 15, 2007 Sheet 17 of 19
`
`US 2007/0058595 A1
`
`COMMON PILOT SYMBOL
`CONTROL SYMBOL
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`18
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`ZTE/SAMSUNG 1020-0018
`
`ZTE/SAMSUNG 1020-0018
`
`18
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`COMMON PILOT
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`FIG. 23
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`ZTE/SAMSUNG 1020-0019
`
`19
`
`

`

`Patent Application Publication Mar. 15, 2007 Sheet 19 of 19
`
`US 2007/0058595 A1
`
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`20
`
`ZTE/SAMSUNG 1020-D020
`
`ZTE/SAMSUNG 1020-0020
`
`20
`
`
`

`

`US 2007/0058595 A1
`
`Mar. 15, 2007
`
`METHOD AND APPARATUS FOR REDUCING
`ROUND TRIP LATENCY AND OVERHEAD
`WITHIN A COMMUNICATION SYSTEM
`
`RELATED APPLICATIONS
`
`[0001] This application claims priority to U.S. Provisional
`Application Ser. No. 60/666,494 filed Mar. 30, 2005.
`
`FIELD OF THE INVENTION
`
`[0002] The present invention relates generally to commu-
`nication systems and in particular, to a method and apparatus
`for reducing round-trip latency and overhead within a com-
`munication system.
`
`BACKGROUND OF THE INVENTION
`
`[0003] One of the key requirements for wireless broad-
`band system development, such as in the 3rd generation
`partnership project (3GPP) Long Term Evolution (LTE), is
`reducing latency in order to improve user experience. From
`a link layer perspective,
`the key contributing factor to
`latency is the round-trip delay between a packet transmis-
`sion and an acknowledgment of the packet reception. The
`round-trip delay is typically defined as a number of frames,
`where a frame is the time duration upon which scheduling is
`performed. The round-trip delay itself determines the overall
`automatic repeat request (ARQ) design, including design
`parameters such as the delay between a first and subsequent
`transmission of packets, or the number of hybrid ARQ
`channels (instances). A reduction in latency with the focus
`on defining the optimum frame duration is therefore key in
`developing improved user experience in future communica-
`tion systems. Such systems include enhanced Evolved Uni-
`versal Terrestrial Radio Access (UTRA) and Evolved Uni-
`versal Terrestrial Radio Access Network (UTRAN) (also
`known as EUTRA and EUTRAN) within 3GPP, and evolu-
`tions of communication systems within other technical
`specification generating organizations (such ‘Phase 2’ within
`3GPP2, and evolutions of IEEE 802.11, 802.16, 802.20, and
`802.22).
`
`[0004] Unfortunately, no single frame duration is best for
`different traffic types requiring different quality of service
`(QoS) characteristics or offering differing packet sizes. This
`is especially true when the control channel and pilot over-
`head in a frame is considered. For example, if the absolute
`control channel overhead is constant per user per resource
`allocation and a single user is allocated per frame, a frame
`duration of 0.5 ms would be roughly four times less efficient
`than a frame duration of 2 ms. In addition, different frame
`durations could be preferred by different manufacturers or
`operators, making the development of an industry standard
`or compatible equipment difficult. Therefore, there is a need
`for an improved method for reducing both round-trip latency
`and overhead within a communication system.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0005] FIG. 1 is a block diagram of a communication
`system.
`
`[0006] FIG. 2 is a block diagram of circuitry used to
`perform uplink and downlink transmission.
`
`[0007] FIG. 3 is a block diagram of a radio frame.
`
`[0008]
`frames.
`
`[0009]
`frames.
`
`FIG. 4 shows a sequence of consecutive short
`
`FIG. 5 shows a sequence of consecutive long
`
`FIG. 6 shows a table for a 10 ms radio frame and
`[0010]
`subframes of approximately 0.5 ms, 0.55556 ms, 0.625 ms,
`and 0.67 ms.
`
`FIG. 7 shows examples for the third data column of
`[0011]
`Table 1, with 0.5 ms subframes and 6 subframes per long
`frame (3 ms).
`
`FIG. 8 shows two examples of radio frames based
`[0012]
`on a combination of 2 ms long frames and 0.5 ms short
`frames.
`
`FIG. 9 shows a subframe comprised ofj=10 OFDM
`[0013]
`symbols each with a cyclic prefix 901 of 5.56 us which may
`be used for unicast transmission.
`
`FIG. 10 shows a ‘broadcast’ subframe comprised
`[0014]
`ofj=9 symbols each with a cyclic prefix 1001 of 11.11 us
`which may be used for broadcast transmission.
`
`FIG. 11 shows a table having examples of three
`[0015]
`subframe types.
`
`FIG. 12 shows a long frame composed entirely of
`[0016]
`broadcast subframes or composed entirely of normal (uni-
`cast) subframes.
`
`FIG. 13 shows a short frame composed of either a
`[0017]
`normal or a broadcast subframe and one or more broadcast
`
`type short frames.
`
`FIG. 14 shows an example of the radio frame
`[0018]
`overhead.
`
`FIG. 15 shows an alternate Radio Frame structure
`[0019]
`of arbitrary size where the synchronization and control
`(S+C) region is not part of a radio frame but part of a larger
`hierarchical
`frame structure composed of radio frames
`where the (S+C) region is sent with every j Radio Frames.
`
`FIG. 16 and FIG. 17 illustrate a hierarchical frame
`[0020]
`structure where a Super frame is defined to be composed of
`n+1 radio frames.
`
`FIG. 18 shows the uplink subframes to be of the
`[0021]
`same configuration as the downlink subframes.
`
`FIG. 19 through FIG. 21 show 2 ms long frames
`[0022]
`composed of 0.5 ms subframes that are of frame type long
`RACH, Data, or Composite.
`
`FIG. 22 through FIG. 24 show short frame fre-
`[0023]
`quency selective (FS) and frequency diverse (FD) resource
`allocations respectively for several users.
`
`DETAILED DESCRIPTION OF THE DRAWINGS
`
`In order to address the above-mentioned need, a
`[0024]
`method and apparatus for reducing round-trip latency is
`provided herein. During operation radio frames are divided
`into a plurality of subframes. Data is transmitted over the
`radio frames within a plurality of subframes, and having a
`frame duration selected from two or more possible frame
`durations.
`
`[0025] The present invention encompasses a method for
`reducing round-trip latency within a communication system.
`
`21
`
`ZTE/SAMSUNG 1020-0021
`
`ZTE/SAMSUNG 1020-0021
`
`21
`
`

`

`US 2007/0058595 A1
`
`Mar. 15, 2007
`
`The method comprises the steps of receiving data to be
`transmitted over a radio frame, where the radio frame is
`comprised of a plurality of subframes. A frame duration is
`selected from two or more possible frame durations, where
`a frame is substantially equal to a multiple of subframes. The
`data is placed within the multiple subframes to produce
`multiple subframes of data, and the frame is transmitted
`having the multiple subframes of data over the radio frame.
`
`invention additionally comprises a
`[0026] The present
`method comprising the steps of receiving data to be trans-
`mitted to a first user over a radio frame, where the radio
`frame is comprised of a plurality of subframes. A frame
`duration is selected for the first user from two or more
`
`possible frame durations, where a frame is substantially
`equal to a multiple of subframes. The data for the first user
`is placed within the multiple subframes to produce multiple
`subframes of data and then transmitted to the first user
`
`having the multiple subframes of data over the radio frame.
`Second data is received to be transmitted to a second user
`over the radio frame. A second frame duration is selected for
`
`the second user from the two or more possible frame
`durations, where a second frame is substantially equal to
`multiple of subframes. The second data for the second user
`is placed within the multiple subframes to produce second
`multiple subframes of data, and the second frame is trans-
`mitted to the second user having the second multiple sub-
`frames of data over the radio frame.
`
`[0027] The present invention encompasses a method for
`transmitting data within a communication system. The
`method comprises the steps of receiving data to be trans-
`mitted over a radio frame, where the radio frame is com-
`prised of a plurality of subframes. A frame length is selected
`comprising multiple subframes and a subframe type is
`selected from one of two or more types of subframes for the
`multiple of subframes. The data is placed within the multiple
`subframes to produce multiple subframes of data and the
`frame is transmitted having the multiple subframes of data
`and the subframe type over the radio frame.
`
`[0028] The present invention encompasses a method for
`transmitting data within a communication system. The
`method comprises the steps of receiving data to be trans-
`mitted over a radio frame, where the radio frame is com-
`prised of a plurality of subframes. A frame is selected
`wherein the frame is substantially equal to a multiple of
`subframes. The data is placed within the multiple subframes
`to produce multiple subframes of data and a common pilot
`is placed within each subframe of the multiple subframes.
`The frame having the multiple subframes of data is trans-
`mitted over the radio frame.
`
`[0029] The present invention encompasses a method for
`transmitting data within a communication system. The
`method comprises the steps of determining a system band-
`width from two or more system bandwidths and receiving
`data to be transmitted over a radio frame and the system
`bandwidth. The radio frame is comprised of a plurality of
`subframes, and a radio frame duration and a subframe
`duration is based on the system bandwidth. A frame is
`selected, where a frame is substantially equal to a multiple
`of subframes. The data is placed within the multiple sub-
`frames to produce multiple subframes of data and the frame
`is transmitted having the multiple subframes of data and the
`subframe type over the radio frame.
`
`[0030] A method for transmitting data within a commu-
`nication system. The method comprises the steps of deter-
`mining a carrier bandwidth and receiving data to be trans-
`mitted over a radio frame, where the radio frame is
`comprised of a plurality of subframes. A frame is selected,
`where the frame is substantially equal
`to a multiple of
`subframes and each subframe is comprised of resource
`elements, where a resource element comprises multiples of
`sub-carriers such that a carrier bandwidth is divided into a
`
`number of resource elements. The data is placed within the
`multiple subframes to produce multiple subframes of data
`and the frame is transmitted having the multiple subframes
`of data and the subframe type over the radio frame.
`
`[0031] Turning now to the drawings, wherein like numer-
`als designate like components, FIG. 1 is a block diagram of
`communication system 100. Communication system 100
`comprises a plurality of cells 105 (only one shown) each
`having a base transceiver station (BTS, or base station) 104
`in communication with a plurality of remote, or mobile units
`101-103. In the preferred embodiment of the present inven-
`tion, communication system 100 utilizes a next generation
`Orthogonal Frequency Division Multiplexed (OFDM) or
`multicarrier based architecture, such as OFDM with or
`without cyclic prefix or guard interval (e.g., conventional
`OFDM with cyclic prefix or guard interval, OFDM with
`pulse shaping and no cyclic prefix or guard interval (OFDM/
`OQAM with IOTA (Isotropic Orthogonal Transform Algo-
`rithm) prototype filter), or single carrier with or without
`cyclic prefix or guard interval (e.g., IFDMA, DFT-Spread-
`OFDM), or other. The data transmission may be a downlink
`transmission or an uplink transmission. The transmission
`scheme may include Adaptive Modulation and Coding
`(AMC). The architecture may also include the use of spread-
`ing techniques such as multi-carrier CDMA (MC-CDMA),
`multi-carrier direct sequence CDMA (MC-DS-CDMA),
`Orthogonal Frequency and Code Division Multiplexing
`(OFCDM) with one or two dimensional spreading, or may
`be based on simpler time and/or frequency division multi-
`plexing/multiple access techniques, or a combination of
`these various techniques. However,
`in alternate embodi-
`ments communication system 100 may utilize other wide-
`band cellular communication system protocols such as, but
`not limited to, TDMA or direct sequence CDMA.
`
`In addition to OFDM, communication system 100
`[0032]
`utilizes Adaptive Modulation and Coding (AMC). With
`AMC, the modulation and coding format of a transmitted
`data stream for a particular receiver is changed to predomi-
`nantly match a current received signal quality (at
`the
`receiver) for the particular frame being transmitted. The
`modulation and coding scheme may change on a frame-by-
`frame basis in order to track the channel quality variations
`that occur in mobile communication systems. Thus, streams
`with high quality are typically assigned higher order modu-
`lations rates and/or higher charmel coding rates with the
`modulation order and/or the code rate decreasing as quality
`decreases. For those receivers experiencing high quality,
`modulation schemes such as 16 QAM, 64 QAM or 256
`QAM are utilized, while for those experiencing low quality,
`modulation schemes such as BPSK or QPSK are utilized.
`
`[0033] Multiple coding rates may be available for each
`modulation scheme to provide finer AMC granularity,
`to
`enable a closer match between the quality and the transmit-
`ted signal characteristics (e.g., R=%, 1/2, and 3/: for QPSK;
`22
`
`ZTE/SAMSU NG 1020-0022
`
`ZTE/SAMSUNG 1020-0022
`
`22
`
`

`

`US 2007/0058595 A1
`
`Mar. 15, 2007
`
`R=1/2 and R=2/3 for 16 QAM, etc.). Note that AMC can be
`performed in the time dimension (e.g., updating the modu-
`lation/coding every Nt OFDM symbol periods) or in the
`frequency dimension (e.g., updating the modulation/coding
`every NSC subcarriers) or a combination of both.
`
`[0034] The selected modulation and coding may only
`predominantly match the current received signal quality for
`reasons such as charmel quality measurement delay or errors
`or channel quality reporting delay. Such latency is typically
`caused by the round-trip delay between a packet transmis-
`sion and an acknowledgment of the packet reception.
`
`In order to reduce latency, a Radio Frame (RAF)
`[0035]
`and subframe are defined such that the RAF is divided into
`
`a number (an integer number in the preferred embodiment)
`of subframes. Within a radio frame, frames are constructed
`from an integer number of subframes for data transmission,
`with two or more frame durations available (e.g., a first
`frame duration of one subframe, and a second frame dura-
`tion of three subframes).
`
`[0036] For example, a 10 ms core radio frame structure
`from UTRA may be defined, with Nrf subframes per radio
`frame (e.g., Nf20 TSf=0.5 ms subframes, where TSf=dura-
`tion of one subframe). For OFDM transmission, subframes
`comprise an integer number P of OFDM symbol intervals
`(e.g., P=l0 for TSn=5 us symbols, where TSn=duration of one
`OFDM symbol), and one or more subframe types may be
`defined based on guard interval or cyclic prefix (e.g., normal
`or broadcast).
`
`[0037] As one of ordinary skill in the art will recognize, a
`frame is associated with a scheduled data transmission. A
`
`frame may be defined as a resource that is ‘schedulable’, or
`a schedulable unit,
`in that
`it has an associated control
`structure—possibly uniquely associated—that controls the
`usage of the resource (i.e. allocation to users etc.). For
`example, when a user is to be scheduled on a frame, a
`resource allocation message corresponding to a frame will
`provide resources (e.g., for an OFDM system a number of
`modulation symbols each of one subcarrier on one OFDM
`symbol) in the frame for transmission. Acknowledgements
`of data transmissions on a frame will be returned, and new
`data or a retransmission of data may be scheduled in a future
`frame. Because not all resources in a frame may be allocated
`in a resource allocation (such as in an OFDM system), the
`resource allocation may not span the entire available band-
`width and/or time resources in a frame.
`
`[0038] The different frame durations may be used to
`reduce latency and overhead based on the type of traffic
`served. For example, if a first transmission and a retrans-
`mission are required to reliably receive a voice over internet
`protocol (VoIP) data packet, and a retransmission can only
`occur after a one frame delay, allocating resources within a
`0.5 ms frame instead of a 2 ms frame reduces latency for
`reliable reception from 6 ms (transmission,
`idle frame,
`retransmission) to 1.5 ms. In another example, providing a
`resource allocation that will fit a user’s packet without
`fragmentation, such as a 1 ms frame instead of a 0.5 ms
`frame, can reduce overhead such as control and acknowl-
`edgement signaling for multiple fragments of a packet.
`
`aggregation of
`the
`reflecting
`names
`[0039] Other
`resources such as consecutive OFDM symbols may be used
`instead of subframe, frame, and radio frame. For example,
`
`the term ‘slot’ may be used for ‘subframe’, or ‘transmission
`time interval (TTI)’ used for ‘frame’ or ‘frame duration’. In
`addition, a frame may be considered a user transmission
`specific quantity (such as a TTI associated with a user and
`a data flow), and frames therefore need not be synchronized
`or aligned between users or even transmissions from the
`same user (e.g., one subframe could contain parts of two
`data transmissions from a user, the first transmitted in a one
`subframe frame and the second transmitted in a four sub-
`
`frame frame). Of course, it may be advantageous to restrict
`either transmissions with a user or transmissions with mul-
`
`tiple users to have synchronized or aligned frames, such as
`when time is divided into a sequence of 0.5 ms or 2 ms
`frames and all resource allocations must be within these
`
`frames. As indicated above a radio frame can represent an
`aggregati