(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2002/0141355 A1
`(43) Pub. Date:
`Oct. 3, 2002
`Struhsaker et al.
`
`US 20020141355A1
`
`(54)
`
`WIRELESS ACCESS SYSTEM AND
`ASSOCIATED METHOD USING MULTIPLE
`MODULATION FORMATS IN TDD FRAMES
`ACCORDING TO SUBSCRIBER SERVICE
`TYPE
`
`(76) Inventors: Paul F. Struhsaker, Plano, TX (US);
`Robert R. Nelson, Dallas, TX (US);
`Russell C. McKoWn, Richardson, TX
`(Us)
`Correspondence Address:
`William A. Munck, Esq.
`NOVAKOV DAVIS & MUNCK, RC.
`900 Three Galleria Tower
`13155 Noel Road
`Dallas, TX 75240 (US)
`
`(21)
`(22)
`
`Appl. No.:
`
`09/839,456
`
`Filed:
`
`Apr. 20, 2001
`
`Related US. Application Data
`
`(60) Provisional application No. 60/262,712, ?led on Jan.
`19, 2001. Provisional application No. 60/262,825,
`?led on Jan. 19, 2001. Provisional application No.
`60/262,698, ?led on Jan. 19, 2001. Provisional appli
`cation No. 60/262,827, ?led on Jan. 19, 2001. Pro
`visional application No. 60/262,826, ?led on Jan. 19,
`2001. Provisional application No. 60/262,951, ?led
`on Jan. 19, 2001. Provisional application No. 60/262,
`824, ?led on Jan. 19, 2001. Provisional application
`No. 60/263,101, ?led on Jan. 19, 2001. Provisional
`application No. 60/263,097, ?led on Jan. 19, 2001.
`Provisional application No. 60/273,579, ?led on Mar.
`
`5, 2001. Provisional application No. 60/262,955, ?led
`on Jan. 19, 2001. Provisional application No. 60/262,
`708, ?led on Jan. 19, 2001. Provisional application
`No. 60/273,689, ?led on Mar. 5, 2001. Provisional
`application No. 60/270,378, ?led on Feb. 21, 2001.
`Provisional application No. 60/270,385, ?led on Feb.
`21, 2001. Provisional application No. 60/270,430,
`?led on Feb. 21, 2001.
`
`Publication Classi?cation
`
`(51) Int. Cl? .............................. .. H04J 3/00; H04Q 7/00
`(52) US. Cl. .......................................... .. 370/280; 370/328
`
`(57)
`
`ABSTRACT
`
`There is disclosed a radio frequency (RF) modem shelf for
`use in a ?xed Wireless access network comprising a plurality
`of base stations capable of bidirectional time division duplex
`(TDD) communication With Wireless access devices dis
`posed at a plurality of subscriber premises. The radio
`frequency (RF) modem shelf comprises: 1) a ?rst RF
`modem capable of communicating With a plurality of the
`Wireless access devices using TDD frames, each TDD frame
`having an uplink for receiving data and a doWnlink for
`transmitting data; and 2) a modulation controller associated
`With the RF modem shelf capable of determining an opti
`mum modulation con?guration for each of the plurality of
`Wireless access devices communicating With the ?rst RF
`modem, Wherein the modulation controller causes the ?rst
`RF modem to transmit ?rst doWnlink data to a ?rst Wireless
`access device in a ?rst data block having a ?rst optimum
`modulation con?guration and to transmit second doWnlink
`data to the ?rst Wireless access device in a second data block
`having a different second optimum modulation con?gura
`tion.
`
`100 /
`
`132
`
`122
`
`CENTRAL OFFICE
`
`165
`
`Aggggs I
`'
`
`- 166
`
`PSTN/
`IPNETWORK
`
`= 150
`
`133
`
`513123
`
`‘P
`160
`
`167
`Q“
`
`ERIC-1021
`Ericsson v. IV, IPR2015-01664
`Page 1 of 24
`
`

`
`Patent Application Publication
`
`Oct. 3, 2002 Sheet 1 0f 8
`
`US 2002/0141355 A1
`
`/ 100
`
`132
`
`133
`
`123
`
`H
`
`F|GURE1
`
`PSTN/ IP NETWORK
`
`ERIC-1021
`Page 2 of 24
`
`

`
`Patent Application Publication
`
`Oct. 3, 2002 Sheet 2 0f 8
`
`US 2002/0141355 A1
`
`140C
`
`6-1405
`
`2%
`
`140A
`
`1108
`
`110A
`
`1605
`
`150
`
`FIGURE 2
`
`ERIC-1021
`Page 3 of 24
`
`

`
`Patent Application Publication
`
`Oct. 3, 2002 Sheet 3 0f 8
`
`US 2002/0141355 A1
`
`lL|—————— X MILLISECOND TDD HYPERFRAME —————i;l 310
`311 l 312 i 313 |
`.
`3
`0
`i 314 | 315 i 316
`/
`\\\\\
`
`\\\
`r/
`,<1__—- 20 MILLISECOND TDD SUPERFRAME A
`
`/
`/
`/
`/
`
`\ \ \
`\\ \
`\ \
`\ \ \
`
`TDD
`TDD
`TDD
`FRAME 0 FRAME 1 FRAME 2
`
`.
`
`.
`
`.
`
`TDD
`FRAME 9
`
`,
`4
`320 //
`/
`/
`/
`/
`/
`
`4
`321
`
`\1\\\
`322
`\\\\
`\\ \
`\\\
`\\
`\ \
`\ \ \
`
`4
`324
`
`l
`§F—-——— 2 MSEO TDD FRAME
`k1” DOWNLINK —_-——il<;——g UPLINK
`FRAME
`‘
`HEADER
`\
`
`CONTENTION
`
`o o I
`
`3
`————i>|
`
`{
`
`i
`
`A
`330
`
`11> A 4
`341342343
`
`6_ D9
`F“?
`350
`
`1 ‘P 4
`1
`360 361362363
`
`FIGURE3
`
`ERIC-1021
`Page 4 of 24
`
`

`
`Patent Application Publication
`
`Oct. 3, 2002 Sheet 4 0f 8
`
`US 2002/0141355 A1
`
`FRONT PANEL INTERFACE
`
`410
`
`MASTER ExTER.
`SESJEE'E SOURCE 1 SEC.
`A
`OUT
`CLOCK
`1114411 I134 412
`1
`L
`
`421
`4 LP
`
`422
`< ‘P
`423
`
`T
`
`ExTER.
`SOURCE
`B
`413 1+ 414
`
`4'? EXTERNAL SOURCE A (BITS)
`
`4
`
`V EXTERNAL SOURCE B (GPS)
`
`424
`‘I7
`
`425
`67
`
`41> EXTERNAL1 SECOND CLOCK
`NETWORK REF. (A/B)
`
`MASTER CLOCK BUS
`
`V
`
`L
`1/0
`
`‘
`
`471
`
`ICP
`
`‘F
`470
`
`F
`
`4 450
`
`Y _
`
`PLL/CLK
`GENER.
`
`s
`
`453
`
`v M
`U ___
`\______B X
`TE *7‘ 452
`
`451
`
`V0
`
`451
`
`v0
`
`L?
`
`ICP
`
`‘F
`460
`
`MASTER ICP
`
`SPARE ICP
`
`<1~ 480
`
`140
`
`FIGURE 4
`
`ERIC-1021
`Page 5 of 24
`
`

`
`Patent Application Publication
`
`Oct. 3, 2002 Sheet 5 0f 8
`
`US 2002/0141355 A1
`
`ERIC-1021
`Page 6 of 24
`
`

`
`Patent Application Publication
`
`Oct. 3, 2002 Sheet 6 0f 8
`
`US 2002/0141355 A1
`
`RF MODEM SHELF RECEIVES NEW ACCESS REQUESTS FROM
`SUBSCRIBER ACCESS DEVICES AND DETERMINES TRAFFIC
`REQUIREMENTS FOR EACH NEW AND EXISTING SUBSCRIBER <P 605
`IN EACH SECTOR OF A SINGLE CELL SITE
`
`RF MODEM SHELF DETERMINES FROM SUBSCRIBER TRAFFIC
`REQUIREMENTS THE LONGEST DOWNLINK PORTION OF ANY <- 610
`TDD FRAME IN EACH SECTOR OF A SINGLE CELL SITE
`
`I
`
`ACCESS PROCESSOR (OR RF MODEM SHELF) DETERMINES
`ALLOCATION OF DOWNLINK AND UPLINK PORTIONS OF TDD
`FRAMES FOR A SINGLE CELL SITE IN ORDER TO MINIMIzE
`OR ELIMINATE INTERFERENCE WITHIN THE CELL SITE.
`
`6“ 615
`
`I
`
`ACCESS PROCESSOR DETERMINES THE LONGEST DOWNLINK
`PORTION OF ANY TDD FRAME ACROSS SEVERAL CLOSELY
`LOCATED CELL SITES
`
`<1- 620
`
`7
`ACCESS PROCESSOR DETERMINES ALLOCATION OF UPLINK
`AND DOWNLINK PORTIONS OF TDD FRAMES ACROSS SEVERAL
`CLOSELY LOCATED CELL SITES IN ORDER TO MINIMIZE
`T 625
`OR ELIMINATE CELL-TO-CELL INTERFERENCE.
`
`I
`
`DOWNLINK PORTIONS OF TDD FRAMES ARE LAUNCHED
`SIMULTANEOUSLY USING DISTRIBUTED TIMING ARCHITECTURE 6
`
`630
`
`600
`
`CONTINUE I
`
`FIGURE 6
`
`ERIC-1021
`Page 7 of 24
`
`

`
`Patent Application Publication
`
`Oct. 3, 2002 Sheet 7 0f 8
`
`US 2002/0141355 A1
`
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`
`RF MODEM SHELF MONITORS DATA TRAFFIC BETWEEN SUBSCRIBERS
`AND BASE STATION AND DETERMINES FOR EACH SUBSCRIBER THE
`MOST EFFICIENT COMBINATION OF MODULATION FORMAT, FEC CODE.
`AND/OR ANTENNA BEAM FORMING FOR THE UPLINK AND DOWNLINK. Q" 705
`DIFFERENT MODULATION FORMAT AND FEC CODE MAY BE USED FOR
`DIFFERENT SERVICES (e.g., vOICE, DATA) USED BY A SUBSCRIBER
`
`I
`
`RF MODEM SHELF ASSIGNS SUBSCRIBERS TO MODULATION
`GROUPS IN DOWNLINK AND TO SUB-BURST GROUPS IN UPLINK.
`
`<1- 710
`
`I
`BASE STATION TRANSMITS MEDIA ACCESS FIELDS (e.g., SIGNALING,
`ACK & NACK) USING LOWEST MODULATION FORMAT/FEC CODE
`COMPLEXITY. BASE STATION TRANSMITS MODULATION GROUPS
`TO SUBSCRIBERS IN INCREASING ORDER OF MODULATION FORMAT/
`FEC CODE COMPLEXITY
`
`<1- 715
`
`BI
`
`BASE STATION RECEIVES REGISTRATION & CONTENTION MINISLOTS T
`USING LOWEST MODULATION FORMAT/FEC CODE COMPLEXITY. BASE
`STATION RECEIVES SUB-BURST GROUPS FROM SUBSCRIBERS IN
`INCREASING ORDER OF MODULATION FORMAT/ FEC CODE
`COMPLEXITY
`
`<I_ 720
`
`I
`l I
`I I
`
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`
`700
`
`<2
`CONTINUE
`
`FIGURE 7
`
`ERIC-1021
`Page 8 of 24
`
`

`
`Patent Application Publication
`
`Oct. 3, 2002 Sheet 8 0f 8
`
`US 2002/0141355 A1
`
`I
`‘
`I
`I
`I
`I
`I
`I
`I
`
`I
`I
`I
`I
`I
`I
`I
`I
`I
`:
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`
`RF MODEM SHELF ASSIGNS CONNECTION ID VALUES TO THE UPLINK
`AND TO THE UPLINK CONNECTIONS USED BY A SUBSCRIBER. IF
`SUBSCRIBER USES MORE THAN ONE SERVICE (e.g., TWO VOICE,
`ONE DATA), RF MODEM SHELF ASSIGNS SEPARATE CID VALUES TO
`EACH UPLINK AND SEPARATE CID VALUES TO EACH DOWNLINK
`
`<I- 805
`
`I
`
`RF MODEM SHELF MONITORS DATA TRAFFIC BETWEEN SUBSCRIBER
`AND BASE STATION AND DETERMINES FOR EACH CONNECTION THE
`MOST EFFICIENT COMBINATION OF MODULATION FORMAT, FEC CODE,
`AND/OR ANTENNA BEAM FORMING FOR THE UPLINK AND DOWNLINK.
`
`A,
`
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`I
`RF MODEM SHELF ASSIGNS EACH SUBSCRIBER CONNECTION TO A
`MODULATION GROUP IN DOWNLINK AND TO A SUB-BURST GROUP IN 6» 815 |
`UPLINK
`I
`I
`I
`
`I
`BASE STATION TRANSMITS MEDIA ACCESS FIELDS (e.g., SIGNALING,
`ACK & NACK) USING LOWEST MODULATION FORMAT/FEC CODE
`COMPLEXITY. BASE STATION TRANSMITS MODULATION GROUPS
`TO SUBSCRIBERS IN INCREASING ORDER OF MODULATION FORMAT/
`FEC CODE COMPLEXITY
`
`6- 820
`
`I
`
`BASE STATION RECEIVES REGISTRATION & CONTENTION MINISLOTS
`USING LOWEST MODULATION FORMAT/FEC CODE COMPLEXITY. BASE
`STATION RECEIVES SUB-BURST GROUPS FROM SUBSCRIBERS IN
`INCREASING ORDER OF MODULATION FORMAT/ FEC CODE
`COMPLEXITY
`
`<I_ 825
`
`/@
`
`800
`
`CONTINUE
`
`FIGURE 8
`
`I
`
`I
`I
`I
`l
`I
`I
`I
`I
`I
`I
`I
`I
`I
`
`ERIC-1021
`Page 9 of 24
`
`

`
`US 2002/0141355 A1
`
`Oct. 3, 2002
`
`WIRELESS ACCESS SYSTEM AND ASSOCIATED
`METHOD USING MULTIPLE MODULATION
`FORMATS IN TDD FRAMES ACCORDING TO
`SUBSCRIBER SERVICE TYPE
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`
`[0001] The present invention is related to those disclosed
`in the following United States Provisional and Non-Provi
`sional Patent Applications:
`
`[0002] 1) Ser. No. 09/713,684, ?led on Nov. 15, 2000,
`entitled “SUBSCRIBER INTEGRATED ACCESS DEVICE
`FOR USE IN WIRELESS AND WIRELINE ACCESS SYS
`TEMS”;
`[0003] 2) [Docket No. WEST14-00005] ?led concurrently
`hereWith, entitled “WIRELESS COMMUNICATION SYS
`TEM USING BLOCK FILTERING AND FAST EQUAL
`IZATION-DEMODULATION AND METHOD OF
`OPERATION”;
`[0004] 3) [Docket No. WEST14-00014], ?led concur
`rently hereWith, entitled “APPARATUS AND ASSOCI
`ATED METHOD FOR OPERATING UPON DATA SIG
`NALS RECEIVED AT A RECEIVING STATION OF A
`FIXED
`
`[0005] WIRELESS ACCESS COMMUNICATION SYS
`TEM”;
`[0006] 4) [Docket No. WEST14-00015], ?led concur
`rently hereWith, entitled “APPARATUS AND METHOD
`FOR OPERATING A SUBSCRIBER INTERFACE IN A
`FIXED WIRELESS SYSTEM”;
`
`[0007] 5) [Docket No. WEST14-00016], ?led concur
`rently hereWith, entitled “APPARATUS AND METHOD
`FOR CREATING SIGNAL AND PROFILES AT A
`RECEIVING STATION”;
`
`[0008] 6) [Docket No. WEST14-00017], ?led concur
`rently hereWith, entitled “SYSTEM AND METHOD FOR
`INTERFACE BETWEEN A SUBSCRIBER MODEM AND
`SUBSCRIBER PREMISES INTERFACES”;
`
`[0009] 7) [Docket No. WEST14-00018], ?led concur
`rently hereWith, entitled “BACKPLAN E ARCHITECTURE
`FOR USE IN WIRELESS AND WIRELINE ACCESS SYS
`TEMS”;
`[0010] 8) [Docket No. WEST14-00019], ?led concur
`rently hereWith, entitled “SYSTEM AND METHOD FOR
`ON-LINE INSERTION OF LINE REPLACEABLE UNITS
`IN WIRELESS AND WIRELINE ACCESS SYSTEMS”;
`
`[0011] 9) [Docket No. WEST14-00020], ?led concur
`rently hereWith, entitled “SYSTEM FOR COORDINATION
`OF TDD TRANSMISSION BURSTS WITHIN AND
`BETWEEN CELLS IN A WIRELESS ACCESS SYSTEM
`AND METHOD OF OPERATION”;
`
`[0012] 10) [Docket No. WEST14-00021], ?led concur
`rently hereWith, entitled “REDUNDANT TELECOMMU
`NICATION SYSTEM USING MEMORY EQUALIZA
`TION APPARATUS AND METHOD OF OPERATION”;
`
`[0013] 11) [Docket No. WEST14-00022], ?led concur
`rently hereWith, entitled “WIRELESS ACCESS SYSTEM
`
`FOR ALLOCATING AND SYNCHRONIZING UPLINK
`AND DOWNLINK OF TDD FRAMES AND METHOD
`OF OPERATION”;
`[0014] 12) [Docket No. WEST14-00023], ?led concur
`rently hereWith, entitled “TDD FDD AIR INTERFACE”;
`[0015] 13) [Docket No. WEST14-00024], ?led concur
`rently hereWith, entitled “APPARATUS, AND AN ASSO
`CIATED METHOD, FOR PROVIDING WLAN SERVICE
`IN A FIXED WIRELESS ACCESS COMMUNICATION
`SYSTEM”;
`[0016] 14) [Docket No. WEST14-00026], ?led concur
`rently hereWith, entitled “WIRELESS ACCESS SYSTEM
`USING MULTIPLE MODULATION”];
`[0017] 15) [Docket No. WEST14-00028], ?led concur
`rently hereWith, entitled “APPARATUS FOR ESTABLISH
`ING A PRIORITY CALL IN A FIXED WIRELESS
`ACCESS COMMUNICATION SYSTEM”;
`
`[0018] 16) [Docket No. WEST14-00029], ?led concur
`rently hereWith, entitled “APPARATUS FOR REALLO
`CATING COMMUNICATION RESOURCES TO ESTAB
`LISH A PRIORITY CALL IN A FIXED WIRELESS
`ACCESS COMMUNICATION SYSTEM”;
`
`[0019] 17) [Docket No. WEST14-00030], ?led concur
`rently hereWith, entitled “METHOD FOR ESTABLISHING
`A PRIORITY CALL IN A FIXED WIRELESS ACCESS
`COMMUNICATION SYSTEM”;
`
`[0020] 18) [Docket No. WEST14-00033], ?led concur
`rently hereWith, entitled “SYSTEM AND METHOD FOR
`PROVIDING AN IMPROVED COMMON CONTROL
`BUS FOR USE IN ON-LINE INSERTION OF LINE
`REPLACEABLE UNITS IN WIRELESS AND WIRELINE
`ACCESS SYSTEMS”;
`
`[0021] 19) Ser. No. 60/262,712, ?led on Jan. 19, 2001,
`entitled “WIRELESS COMMUNICATION SYSTEM
`USING BLOCK FILTERING AND FAST
`
`[0022] EQUALIZATION-DEMODULATION
`AND
`WEST14
`METHOD OF OPERATION”[Docket No.
`00005];
`[0023] 20) Serial No. 60/262,825, ?led on Jan. 19, 2001,
`entitled “APPARATUS AND ASSOCIATED METHOD
`FOR OPERATING UPON DATA SIGNALS RECEIVED
`AT A RECEIVING STATION OF A FIXED WIRELESS
`ACCESS COMMUNICATION SYSTEM”[Docket No.
`WEST14-00014];
`[0024] 21) Serial No. 60/262,698, ?led on Jan. 19, 2001,
`entitled “APPARATUS AND METHOD FOR OPERATING
`A SUBSCRIBER INTERFACE IN A FIXED WIRELESS
`SYSTEM”[Docket No. WEST14-00015];
`[0025] 22) Serial No. 60/262,827, ?led on Jan. 19, 2001,
`entitled “APPARATUS AND METHOD FOR CREATING
`SIGNAL AND PROFILES AT A RECEIVING STATION”
`[Docket No. WEST14-00016];
`[0026] 23) Serial No. 60/262,826, ?led on Jan. 19, 2001,
`entitled “SYSTEM AND METHOD FOR INTERFACE
`BETWEEN A SUBSCRIBER MODEM AND SUB
`SCRIBER PREMISES INTERFACES”[Docket No.
`WEST14-00017];
`
`ERIC-1021
`Page 10 of 24
`
`

`
`US 2002/0141355 A1
`
`Oct. 3, 2002
`
`[0027] 24) Serial No. 60/262,951, ?led on Jan. 19, 2001,
`entitled “BACKPLANE ARCHITECTURE FOR USE IN
`WIRELESS AND WIRELINE ACCESS SYSTEMS”
`[Docket No. WEST14-00018];
`[0028] 25) Serial No. 60/262,824, ?led on Jan. 19, 2001,
`entitled “SYSTEM AND METHOD FOR ON-LINE
`INSERTION OF LINE REPLACEABLE UNITS IN WIRE
`LESS AND WIRELINE ACCESS SYSTEMS”[Docket No.
`WEST14-00019];
`[0029] 26) Serial No. 60/263,101, ?led on Jan. 19, 2001,
`entitled “SYSTEM FOR COORDINATION OF TDD
`TRANSMISSION BURSTS WITHIN AND BETWEEN
`CELLS IN A WIRELESS ACCESS SYSTEM AND
`METHOD OF OPERATION”[Docket No. WEST14
`00020];
`[0030] 27) Serial No. 60/263,097, ?led on Jan. 19, 2001,
`entitled “REDUNDANT TELECOMMUNICAT ION SYS
`TEM USING MEMORY EQUALIZATION APPARATUS
`AND METHOD OF OPERATION”[Docket No. WEST14
`00021];
`[0031] 28) Serial No. 60/273,579, ?led Mar. 5, 2001,
`entitled “WIRELESS ACCESS SYSTEM FOR ALLOCAT
`ING AND SYNCHRONIZING UPLINK AND DOWN
`LINK OF TDD FRAMES AND METHOD OF OPERA
`TION”[Docket No. WEST14-00022];
`[0032] 29) Serial NO. 60/262,955, ?led Jan. 19, 2001,
`entitled “TDD FDD AIR INTERFACE”[D0cket NO.
`WEST14-00023];
`[0033] 30) Serial No. 60/262,708, ?led on Jan. 19, 2001,
`entitled “APPARATUS, AND AN ASSOCIATED
`METHOD, FOR PROVIDING WLAN SERVICE IN A
`FIXED WIRELESS ACCESS COMMUNICATION SYS
`TEM”[Docket No. WEST14-00024];
`[0034] 31) Serial NO. 60/273,689, ?led Mar. 5, 2001,
`entitled “WIRELESS ACCESS SYSTEM USING MUL
`TIPLE MODULATION”[D0cket NO. WEST14-00026];
`[0035] 32) Serial NO. 60/270,378, ?led Feb. 21, 2001,
`entitled “APPARATUS FOR ESTABLISHING A PRIOR
`ITY CALL IN A FIXED WIRELESS ACCESS COMMU
`NICATION SYSTEM”[D0cket NO. WEST14-00028];
`[0036] 33) Serial No. 60/270,385, ?led Feb. 21, 2001,
`entitled “APPARATUS FOR REALLOCATING COMMU
`NICAT ION RESOURCES TO ESTABLISH A PRIORITY
`CALL IN A FIXED WIRELESS ACCESS COMMUNICA
`TION SYSTEM”[Docket No. WEST14-00029]; and 34)
`Serial No. 60/270,430, ?led Feb. 21, 2001, entitled
`“METHOD FOR ESTABLISHING APRIORITY CALL IN
`A FIXED WIRELESS ACCESS COMMUNICATION SYS
`TEM”[Docket No. WEST14-00030].
`[0037] The above applications are commonly assigned to
`the assignee of the present invention. The disclosures of
`these related patent applications are hereby incorporated by
`reference for all purposes as if fully set forth herein.
`
`TECHNICAL FIELD OF THE INVENTION
`
`[0038] The present invention is directed, in general, to
`wireless access systems and, more speci?cally, to a burst
`packet transmission media access system for use in a ?xed
`wireless access network.
`
`BACKGROUND OF THE INVENTION
`[0039] Telecommunications access systems provide for
`voice, data, and multimedia transport and control between
`the central of?ce (CO) of the telecommunications service
`provider and the subscriber (customer) premises. Prior to the
`mid-1970s, the subscriber was provided phone lines (e.g.,
`voice frequency (VF) pairs) directly from the Class 5
`switching equipment located in the central of?ce of the
`telephone company. In the late 1970s, digital loop carrier
`(DLC) equipment was added to the telecommunications
`access architecture. The DLC equipment provided an analog
`phone interface, voice CODEC, digital data multiplexing,
`transmission interface, and control and alarm remotely from
`the central of?ce to cabinets located within business and
`residential locations for approximately 100 to 2000 phone
`line interfaces. This distributed access architecture greatly
`reduced line lengths to the subscriber and resulted in sig
`ni?cant savings in both wire installation and maintenance.
`The reduced line lengths also improved communication
`performance on the line provided to the subscriber.
`[0040] By the late 1980s, the limitations of data modem
`connections over voice frequency (VF) pairs were becoming
`obvious to both subscribers and telecommunications service
`providers. ISDN (Integrated Services Digital Network) was
`introduced to provide universal 128 kbps service in the
`access network. The subscriber interface is based on 64 kbps
`digitization of the VF pair for digital multiplexing into high
`speed digital transmission streams (e.g., T1/T 3 lines in
`North America, E1/E3 lines in Europe). ISDN was a logical
`extension of the digital network that had evolved throughout
`the 1980s. The rollout of ISDN in Europe was highly
`successful. However, the rollout in the United States was not
`successful, due in part to arti?cially high tariff costs which
`greatly inhibited the acceptance of ISDN.
`[0041] More recently, the explosion of the Internet and
`deregulation of the telecommunications industry have
`brought about a broadband revolution characteriZed by
`greatly increased demands for both voice and data services
`and greatly reduced costs due to technological innovation
`and intense competition in the telecommunications market
`place. To meet these demands, high speed DSL (digital
`subscriber line) modems and cable modems have been
`developed and introduced. The DLC architecture was
`extended to provide remote distributed deployment at the
`neighborhood cabinet level using DSL access multiplexer
`(DSLAM) equipment. The increased data rates provided to
`the subscriber resulted in upgrade DLC/DSLAM transmis
`sion interfaces from T1/E1 interfaces (1.5/2.0 Mbps) to high
`speed DS3 and OC3 interfaces. In a similar fashion, the
`entire telecommunications network backbone has undergone
`and is undergoing continuous upgrade to wideband optical
`transmission and switching equipment.
`[0042] Similarly, wireless access systems have been
`developed and deployed to provide broadband access to both
`commercial and residential subscriber premises. Initially,
`the market for wireless access systems was driven by rural
`radiotelephony deployed solely to meet the universal service
`requirements imposed by government (ie the local tele
`phone company is required to serve all subscribers regard
`less of the cost to install service). The cost of providing a
`wired connection to a small percentage of rural subscribers
`was high enough to justify the development and expense of
`small-capacity wireless local loop (WLL) systems.
`
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`[0043] Deregulation of the local telephone market in the
`United States (e. g., Telecommunications Act of 1996) and in
`other countries shifted the focus of ?xed Wireless access
`(FWA) systems deployment from rural access to competitive
`local access in more urbaniZed areas. In addition, the age and
`inaccessibility of much of the older Wired telephone infra
`structure makes FWA systems a cost-effective alternative to
`installing neW, Wired infrastructure. Also, it is more eco
`nomically feasible to install FWA systems in developing
`countries Where the market penetration is limited (i.e., the
`number and density of users Who can afford to pay for
`services is limited to small percent of the population) and the
`rollout of Wired infrastructure cannot be performed pro?t
`ably. In either case, broad acceptance of FWA systems
`requires that the voice and data quality of FWA systems must
`meet or exceed the performance of Wired infrastructure.
`
`[0044] Wireless access systems must address a number of
`unique operational and technical issues including:
`[0045] 1) Relatively high bit error rates (BER) compared
`to Wire line or optical systems; and
`[0046] 2) Transparent operation With netWork protocols
`and protocol time constraints for the folloWing protocols:
`[0047] a) ATM;
`[0048] b) Class 5 sWitch interfaces (domestic
`GR-303 and international V5.2);
`[0049] c) TCP/IP With quality-of-service QoS for
`voice over IP (VOIP) (i.e., RTP) and other H.323
`media services;
`[0050] d) Distribution of synchroniZation of netWork
`time out to the subscribers;
`
`[0051] 3) Increased use of voice, video and/or media
`compression and concentration of active traf?c over
`the air interface to conserve bandWidth;
`
`[0052] 4) SWitching and routing Within the access system
`to distribute signals from the central of?ce to multiple
`remote cell sites containing multiple cell sectors and one or
`more frequencies of operation per sector; and
`[0053] 5) Remote support and debugging of the subscriber
`equipment, including remote softWare upgrade and provi
`sioning.
`[0054] Unlike physical optical or Wire systems that oper
`ate at bit error rates (BER) of 10'11 Wireless access systems
`have time varying channels that typically provide bit error
`rates of 10'3 to 10_6. The Wireless physical (PHY) layer
`interface and the media access control (MAC) layer inter
`face must provide modulation, error correction and ARQ
`(automatic request for retransmission) protocol that can
`detect and, Where required, correct or retransmit corrupted
`data so that the interfaces at the netWork and at the sub
`scriber site operate at Wire line bit error rates.
`
`[0055] The Wide range of equipment and technology
`capable of providing either Wireline (i.e., cable, DSL, opti
`cal) broadband access or Wireless broadband access has
`alloWed service providers to match the needs of a subscriber
`With a suitable broadband access solution. HoWever, in
`many areas, the cost of cable modem or DSL service is high.
`Additionally, data rates may be sloW or coverage incomplete
`due to line lengths. In these areas and in areas Where the high
`
`cost of replacing old telephone equipment or the loW density
`of subscribers makes it economically unfeasible to introduce
`either DSL or cable modem broadband access, ?xed Wireless
`broadband systems offer a viable alternative. Fixed Wireless
`broadband systems use a group of transceiver base stations
`to cover a region in the same manner as the base stations of
`a cellular phone system. The base stations of a ?xed Wireless
`broadband system transmit forWard channel (i.e., doWn
`stream) signals in directed beams to ?xed location antennas
`attached to the residences or of?ces of subscribers. The base
`stations also receive reverse channel (i.e., upstream) signals
`transmitted by the broadband access equipment of the sub
`scriber.
`
`[0056] Media access control (MAC) protocols refer to
`techniques that increase utiliZation of tWo-Way communica
`tion channel resources by subscribers that use the channel
`resources. The MAC layer may use a number of possible
`con?gurations to alloW multiple access. These con?gura
`tions include:
`
`[0057] 1. FDMA—frequency division multiple access. In
`a FDMA system, subscribers use separate frequency chan
`nels on a permanent or demand access basis.
`
`[0058] 2. TDMA—time division multiple access. In a
`TDMA system, subscribers share a frequency channel but
`allocate spans of time to different users.
`
`[0059] 3. CDMA—code division multiple access. In a
`CDMA system, subscribers share a frequency but use a set
`of orthogonal codes to alloW multiple access.
`
`[0060] 4. SDMA—space division multiple access—In a
`SDMA system, subscribers share a frequency but one or
`more physical channels are formed using antenna beam
`forming techniques.
`[0061] 5. PDMA—polariZation division multiple access—
`In a PDMA system, subscribers share a frequency but
`change polariZation of the antenna.
`
`[0062] Each of these MAC techniques makes use of a
`fundamental degree of freedom (physical property) of a
`communications channel. In practice, combinations of these
`degrees of freedom are often used. As an example, cellular
`systems use a combination of FDMA and either TDMA or
`CDMA to support a number of users in a cell.
`
`[0063] To provide a subscriber With bi-directional (tWo
`Way) communication in a shared media, such as a coaxial
`cable, a multi-mode ?ber (optical), or an RF radio channel,
`some type of duplexing technique must be implemented.
`Duplexing techniques include frequency division duplexing
`(FDD) and time division duplexing (TDD). In FDD, a ?rst
`channel (frequency) is used for transmission and a second
`channel (frequency) is used for reception. To avoid physical
`interference betWeen the transmit and receive channels, the
`frequencies must have a separation knoW as the duplex
`spacing. In TDD, a single channel is used for transmission
`and reception and speci?c periods of time (i.e., slots) are
`allocated for transmission and other speci?c periods of time
`are allocated for reception.
`
`[0064] Finally, a method of coordinating the use of band
`Width must be established. There are tWo fundamental
`methods: distributed control and centraliZed control. In
`distributed control, subscribers have a shared capability With
`or Without a method to establish priority. An example of this
`
`ERIC-1021
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`Oct. 3, 2002
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`is CSMA (carrier sense multiple access) used in IEEE802.3
`Ethernet and IEEE 802.11 Wireless LAN. In centralized
`control, subscribers are allowed access under the control of
`a master controller. Cellular systems, such as IS-95, IS-136,
`and GSM, are typical examples. Access is granted using
`forms of polling and reservation (based on polled or demand
`access contention).
`[0065] A number of references and overvieWs of demand
`access are available including the folloWing:
`
`[0066] 1. Sklar, Bernard. “Digital Communications Fun
`damentals and Applications,” Prentice Hall, EngleWood
`Cliffs, N.J., 1988. Chapter 9.
`[0067] 2. Rappaport, Theodore. “Wireless Communica
`tions, Principles and Practice,” Prentice Hall, Upper Saddle
`River, N.J., 1996. Chapter 8.
`
`[0068] 3. TR101-173V1.1. “Broadband Radio Access Net
`Works, Inventory of Broadband Radio Technologies and
`Techniques,” ETSI, 1998. Chapter 7.
`[0069] The foregoing references are hereby incorporated
`by reference into the present disclosure as if fully set forth
`herein.
`
`[0070] In 1971, the University of HaWaii began operation
`of a random access shared channel ALOHA TDD system.
`The lack of channel coordination resulted in poor utiliZation
`of the channel. This lead to the introduction of time slots
`(slotted Aloha) that set a level of coordination betWeen the
`subscribers that doubled the channel throughput. Finally, the
`researchers introduced the concept of a central controller
`and the use of reservations (reservation Aloha). Reservation
`techniques made it possible to make trade-offs betWeen
`throughput and latency.
`
`[0071] This Work Was fundamental to the development of
`media access control (MAC) techniques for dynamic ran
`dom access and the use of ARQ (automatic request for
`retransmission) to retransmit erroneous packets. While the
`Work at the University of HaWaii explored the fundamentals
`of burst transmission and random access, the Work did not
`introduce the concept of a frame and/or super-frame struc
`ture to the TDD/TDMA access techniques. One of the more
`sophisticated systems developed in the 1970s and in current
`use is Joint Tactical Information Distribution System
`(JTIDS). This system Was based on the joint use of TDMA
`and time duplexing over frequency-hopping spread-spec
`trum channels. This Was the culmination of research to alloW
`?exible allocation of bandWidth to a large group of users.
`The key aspect of the JTIDS system Was the introduction of
`dynamic allocation of bandWidth resources and explicit
`variable symmetry (doWnlink vs. uplink bandWidth) in the
`link.
`
`[0072] IEEE 802.11 Wireless LAN equipment provides
`for a centrally coordinated TDD system that does not have
`a speci?c frame or slotting structure. IEEE 802.11 did
`introduce the concept of variable modulation and spreading
`inherent in the structure of the transmission bursts. A sig
`ni?cant improvement Was incorporated in US. Pat. No.
`6,052,408, entitled “Cellular Communications System With
`Dynamically Modi?ed Data Transmission Parameters.” This
`patent introduced speci?c burst packet transmission formats
`that provide for adaptive modulation, transmit poWer, and
`antenna beam forming and an associated method of deter
`
`mining the highest data rate for a de?ned error rate ?oor for
`the link betWeen the base station and a plurality of subscrib
`ers assigned to that base station. With the exception of
`variable spreading military systems and NASA space com
`munication systems, this Was one of the ?rst commercial
`patents that address variable transmission parameters to
`increase system throughput.
`[0073] Another example of TDD systems are digital cord
`less phones, also referred to as loW-tier PCS systems. The
`Personal Access Communications (PAC) system and Digital
`European Cordless Telephone (DECT, as speci?ed by ETSI
`document EN 300-175-3) are tWo examples of these sys
`tems. Digital cordless phones met With limited success for
`their intended use as pico-cellular ?xed access products. The
`systems Were subsequently modi?ed and repackaged for
`Wireless local loop (WLL) applications With extended range
`using increased transmission (TX) poWer and greater
`antenna gain.
`
`[0074] These TDD/TDMA systems use ?xed symmetry
`and bandWidth betWeen the uplink and the doWnlink. The
`TDD frame consists of a ?xed set of time slots for the uplink
`and the doWnlink. The modulation index (or type) and the
`forWard error correction (FEC) format for all data transmis
`sions are ?xed in these systems. These systems did not
`include methods for coordinating TDD bursts betWeen sys
`tems. This resulted in inefficient use of spectrum in the
`frequency planning of cells.
`[0075] While DECT and PAC systems based on ?xed
`frames With ?xed and symmetric allocation of time slots (or
`bandWidth) provides excellent latency and loW jitter, and can
`support time bounded services, such as voice and Nx64
`Kbps video, these systems do not provide efficient use of the
`spectrum When asymmetric data services are used. This has
`lead to research and development of packet based TDD
`systems based on Internet protocol (IP) or asynchronous
`transfer mode (ATM), With dynamic allocation of TDD time
`slots and the uplink-doWnlink bandWidth, combined With
`ef?cient algorithms to address both best efforts and real-time
`loW-latency service for converged media access (data and
`multi-media).
`[0076] One example of a TDD system With dynamic slot
`and bandWidth assignment is the ETSI HYPERLAN II
`speci?cation based on the Dynamic Slot Assignment algo
`rithm described in “Wireless ATM: Performance Evaluation
`of a DSA++ MAC Protocol With Fast Collision resolution by
`Probing Algorithm,” D. Petras and A. Kramling, Interna
`tional Journal of Wireless Information NetWorks, Vol. 4, No.
`4, 1997. This system alloWs both contention-based and
`contention-free access to the physical TDD channel slots.
`This system also introduced the broadcast of resource allo
`cation at the start of every frame by the base station
`controller. Other Wireless standards, including IEEE 802.16
`Wireless metropolitan netWork standards, use this combina
`tion of an allocation MAP of the uplink and doWnlink at the
`start of the dynamic TDD frame to set resource use for the
`next TDD frame.
`
`[0077] An further improvement to this TDD system Was
`described in “Multiple Access Control Protocols for Wire
`less AT