fc-pi-5 clause 5 bit error rate test suitev1.0
TRANSCRIPT
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Fibre Channel Consortium
FC-PI-5 Clause 5
Bit Error Rate Test Suite
Version 1.0
Technical Document
Last Updated: September 30, 2014
Fibre Channel Consortium 121 Technology Drive, Suite 2
InterOperability Laboratory Durham, N !"#2$
%niversity o& Ne' ampshire (hone) *1+!"+#2+!!-!
Fa.) *1+!"+#2+$1#1
http)//'''0iol0unh0eu/consortiums/&c
2014 University of New Hampshire InterOperability Laboratory
http://www.iol.unh.edu/consortiums/fchttp://www.iol.unh.edu/consortiums/fc -
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Table of ContentsTable of Contents2
!"#nowle$%ments4Intro$&"tion'
(ro&p 1) *it +rror ,ate-
Test .'11) +le"tri"al *it +rror ,ate /*+,
Test .'12) Opti"al *it +rror ,ate /*+,10!ppen$i !) Test 3et&p12
!ppen$i *) Test atterns15
!ppen$i C) *it +rror ,ate 6eas&rement17
8ibre Channel Consorti&m 2 8C9I9' *it +rror ,ate Test 3&ite v10
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Modification Record !&%&st 14: 2014 ;
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AcknowledgmentsThe University of New Hampshire would like to acknowledge the efforts of the following individuals in the
development of this test suite.
=aniel (ray University of New Hampshire
=aniel ,eynol$s University of New Hampshire
8ibre Channel Consorti&m 4 8C9I9' *it +rror ,ate Test 3&ite v10
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IntroductionOverview
The University of New Hampshire>s InterOperability Laboratory /UNH9IOL is an instit&tion $esi%ne$ to improvethe interoperability of stan$ar$s base$ pro$&"ts by provi$in% an environment where a pro$&"t "an be teste$ a%ainst
other implementations of a stan$ar$ This parti"&lar s&ite of tests has been $evelope$ to help implementers eval&ate
the hysi"al Layer f&n"tionality of their opti"al 8ibre Channel pro$&"ts
These tests are $esi%ne$ to $etermine if a 8ibre Channel pro$&"t "onforms to spe"ifi"ations of the FC-!-"#ev $.%&
8ibre Channel 3tan$ar$ /hereafter referre$ to as ?8C9I9'@ 3&""essf&l "ompletion of all tests "ontaine$ in this
s&ite $oes not %&arantee that the teste$ $evi"e will operate with other $evi"es However: "ombine$ with satisfa"tory
operation in the IOL>s interoperability test be$: these tests provi$e a reasonable level of "onfi$en"e that the $evi"e&n$er test /=UT will f&n"tion properly in many 8ibre Channel environments
Organi'ation of Tests
The tests "ontaine$ in this $o"&ment are or%aniAe$ to simplify the i$entifi"ation of information relate$ to a test an$to fa"ilitate in the a"t&al testin% pro"ess +a"h test "ontains an i$entifi"ation se"tion that $es"ribes the test an$
provi$es "ross9referen"e information The $is"&ssion se"tion "overs ba"#%ro&n$ information an$ spe"ifies why the
test is to be performe$ Tests are %ro&pe$ in or$er to re$&"e set&p time in the lab environment +a"h test "ontains
the followin% information)
Test Num(er
The Test N&mber asso"iate$ with ea"h test follows a simple %ro&pin% str&"t&re Liste$ first is the Cla&se followe$
by the Test (ro&p N&mber followe$ by the testBs n&mber within the %ro&p This allows for the a$$ition of f&t&re
tests to the appropriate %ro&ps of the test s&ite witho&t re&irin% the ren&mberin% of the s&bse&ent tests
urpose
The p&rpose is a brief statement o&tlinin% what the test attempts to a"hieve The test is written at the f&n"tional
level
#eferences
This se"tion spe"ifies all referen"e material externalto the test s&ite: in"l&$in% the spe"ifi" s&b"la&ses referen"es for
the test in &estion: an$ any other referen"es that mi%ht be helpf&l in &n$erstan$in% the test metho$olo%y an$Dor test
res<s +ternal so&r"es are always referen"e$ by a bra"#ete$ n&mber /e%: E1F when mentione$ in the test
$es"ription !ny other referen"es in the test $es"ription that are not in$i"ate$ in this manner refer to elements within
the test s&ite $o"&ment itself /e%: ?!ppen$i 7!@: or ?Table 71191@
#esource #e)uirements
The re&irements se"tion spe"ifies the test har$ware an$Dor software nee$e$ to perform the test This is %enerally
epresse$ in terms of minim&m re&irements: however in some "ases spe"ifi" e&ipment man&fa"t&rerDmo$elinformation may be provi$e$
*ast +odification
This spe"ifies the $ate of the last mo$ifi"ation to this test
,iscussion
The $is"&ssion "overs the ass&mptions ma$e in the $esi%n or implementation of the test: as well as #nown
limitations Other items spe"ifi" to the test are "overe$ here
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Test etup
The set&p se"tion $es"ribes the initial "onfi%&ration of the test environment 3mall "han%es in the "onfi%&ration
sho&l$ be in"l&$e$ in the test pro"e$&re
rocedure
The pro"e$&re se"tion of the test $es"ription "ontains the systemati" instr&"tions for "arryin% o&t the test It
provi$es a "oo#boo# approa"h to testin%: an$ may be intersperse$ with observable res<s
O(serva(le #esults
This se"tion lists the spe"ifi" observable res<s that "an be eamine$ by the tester in or$er to verify that the =UT is
operatin% properly Ghen m<iple val&es for an observable are possible: this se"tion provi$es a short $is"&ssion on
how to interpret them The $etermination of a pass or fail o&t"ome for a parti"&lar test is often base$ on the
s&""essf&l /or &ns&""essf&l $ete"tion of a "ertain observable
ossi(le ro(lems
This se"tion "ontains a $es"ription of #nown iss&es with the test pro"e$&re: whi"h may affe"t test res<s in "ertainsit&ations It may also refer the rea$er to test s&ite appen$i"es an$Dor whitepapers that may provi$e more $etail
re%ar$in% these iss&es
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Group 1: Bit Error Rate
Overview
This %ro&p of tests verifies the +le"tri"al an$ Opti"al *it +rror ,ate /*+,: as $efine$ in Cla&se ' of 8C9I9' These
tests "annot provi$e a %&arantee that the $evi"e "onforms to the *it +rror ,ate: in all "on$itions: as $efine$ in
Cla&se ' of 8C9I9': b&t "an provi$e "onfi$en"e that the $evi"e an$ the *it +rror ,ate Tester /*+,T "onform to
the appli"able *it +rror ,ate
8ibre Channel Consorti&m - 8C9I9' *it +rror ,ate Test 3&ite v10
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Test /".%.% 0lectrical 1it 0rror #ate 210#3
urpose
To verify that the *it +rror ,ate of the =UT is within the "onforman"e limit
#eferences
E1F 8C9I9' 9 Cla&se '1
E2F Ibi$ ; Cla&se 1E5F 8C963J ; !nne !
E4F 8C963J3 ; Cla&se
#esource #e)uirements
+le"tri"al 9*+,T Capable of han$lin% &p to 17(8C si%nalin%
/4 36!D36! "ables
*ast Updated 6ay 04: 200
,iscussion
In or$er to ens&re the overall &ality of the 8ibre Channel lin#: it is important to establish a maim&m allowable
*it +rror ,ate /*+, that $evi"es m&st a"hieve The 8C98395 proto"ol is $efine$ to operate a"ross "onne"tions
havin% a bit error ratio /*+, $ete"te$ at the re"eivin% port of less than 10 912 The *+, obKe"tive is 10912 ! T,
Conne"tion bit error rate /*+, of 10 912as meas&re$ at its re"eiver is s&pporte$ The basis for the *+, is theen"o$e$ serial $ata stream on the transmission me$i&m $&rin% system operation
!ll 8ibre Channel T, Conne"tions $es"ribe$ in referen"e E2F shall operate within the *+, obKe"tive /10 912
atterns for this test are $efine$ by 8C963J E5F for 4(8C an$ 8C963J3 E4F for (8C an$ 17(8C The
implementation of spe"ifi" patterns is mentione$ in the ro"e$&re: an$ is $etermine$ by the spee$ of the $evi"e
&n$er test
Test etup
The =UT sho&l$ be set&p as $efine$ in!ppen$i ! Confi%&re the =UT for the appropriate spee$ The =UTsho&l$ be transitione$ into the monitorin%Da"tive state If the =UT s&pports s"ramblin%) the s"rambler D $e9s"rambler
m&st be $isable$
rocedure
a LMortDNMortD8Mort =evi"e
1 Instr&"t the 9*+,T to transmit a L* to the =UT
2 Instr&"t the 9*+,T to be%in so&r"in% I$le "ontin&o&sly5 6eas&re the *it +rror ,ate over the transmission of 51012transmitte$ bits
4 ,epeat steps 195 for ea"h port
' 8or 4( an$ ( /not s&pportin% s"ramblin% =evi"es
1 ,epeat steps 194 for CT!T: C,!T an$ C3!T7 8or ( =evi"es s&pportin% s"ramblin%
1 ,epeat steps 194 for 3!T an$ T3!T
- 8or 17( =evi"es
1 ,epeat steps 194 &sin% ,*3: ,*351: an$ 3"ramble$ I$le
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b NMortD8Mort =evi"e
1 3et&p the =UT to retransmit &naltere$ traffi" thro&%h the T, Conne"tion2 Instr&"t the 9*+,T to be%in so&r"in% I$le "ontin&o&sly
5 6eas&re the *it +rror ,ate over the transmission of 51012transmitte$ bits
4 ,epeat steps 195 for ea"h port
' 8or 4( an$ ( /not s&pportin% s"ramblin% =evi"es
1 ,epeat steps 194 for CT!T: C,!T an$ C3!T7 8or ( =evi"es s&pportin% s"ramblin%
1 ,epeat steps 194 for 3!T an$ T3!T
- 8or 17( =evi"es
1 ,epeat steps 194 &sin% ,*3: ,*351: an$ 3"ramble$ I$le
O(serva(le #esults
The *it +rror ,ate /*+, over all traffi" shall not e"ee$ 10 912/ie not errors shall be $ete"te$ over the 51012
transmitte$ bits
ossi(le ro(lems None
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Test /".%.4 Optical 1it 0rror #ate 210#3
urpose
To verify that the *it +rror ,ate of the =UT is within the "onforman"e limit
#eferences
E1F 8C9I9' 9 Cla&se '1
E2F Ibi$ ; Cla&se 71E5F 8C963J ; !nne !
E4F 8C963J3 ; Cla&se
#esource #e)uirements
Opti"al 9*+,T Capable of han$lin% &p to 17(8C si%nalin%
/1 8iber Cable
*ast Updated 6ay 04: 200
,iscussion
In or$er to ens&re the overall &ality of the 8ibre Channel lin#: it is important to establish a maim&m allowable
*it +rror ,ate /*+, that $evi"es m&st a"hieve The 8C98395 proto"ol is $efine$ to operate a"ross "onne"tions
havin% a bit error ratio /*+, $ete"te$ at the re"eivin% port of less than 10 912 The *+, obKe"tive is 10912 ! T,
Conne"tion bit error rate /*+, of 10 912as meas&re$ at its re"eiver is s&pporte$ The basis for the *+, is theen"o$e$ serial $ata stream on the transmission me$i&m $&rin% system operation
8ibre Channel lin#s shall not e"ee$ the *+, obKe"tive /10912 &n$er any "ompliant "on$itions atterns for this
test are $efine$ by 8C963J E5F for 4(8C an$ 8C963J3 E4F for (8C an$ 17(8C The implementation of
spe"ifi" patterns is mentione$ in the ro"e$&re: an$ is $etermine$ by the spee$ of the $evi"e &n$er test
Test etup
The =UT sho&l$ be set&p as $efine$ in!ppen$i ! Confi%&re the =UT for the appropriate spee$ The =UT
sho&l$ be transitione$ into the monitorin%Da"tive state
rocedure
a LMortDNMortD8Mort =evi"e
1 Instr&"t the 9*+,T to transmit a L* to the =UT
2 Instr&"t the 9*+,T to be%in so&r"in% I$le "ontin&o&sly
5 6eas&re the *it +rror ,ate over the transmission of 51012transmitte$ bits
4 ,epeat steps 195 for ea"h port' 8or 4( an$ ( /not s&pportin% s"ramblin% =evi"es
1 ,epeat steps 194 for CT!T: C,!T an$ C3!T
7 8or ( =evi"es s&pportin% s"ramblin%
1 ,epeat steps 194 for 3!T an$ T3!T- 8or 17( =evi"es
1 ,epeat steps 194 &sin% ,*3: ,*351: an$ 3"ramble$ I$le
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b NMortD8Mort =evi"e1 3et&p the =UT to retransmit &naltere$ traffi" thro&%h the T, Conne"tion
2 Instr&"t the 9*+,T to be%in so&r"in% I$le "ontin&o&sly
5 6eas&re the *it +rror ,ate over the transmission of 51012transmitte$ bits4 ,epeat steps 195 for ea"h port
' 8or 4( an$ ( /not s&pportin% s"ramblin% =evi"es
1 ,epeat steps 194 for CT!T: C,!T an$ C3!T
7 8or ( =evi"es s&pportin% s"ramblin%
1 ,epeat steps 194 for 3!T an$ T3!T- 8or 17( =evi"es
1 ,epeat steps 194 &sin% ,*3: ,*351: an$ 3"ramble$ I$le
O(serva(le #esults
The *it +rror ,ate /*+, over all traffi" shall not e"ee$ 10 912/ie not errors shall be $ete"te$ over the 51012
transmitte$ bits
ossi(le ro(lems None
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Appendi A: Test !etup
8ibre Channel Consorti&m 12 8C9I9' *it +rror ,ate Test 3&ite v10
Figure % 0lectrical Test etup
I9*+,T
=UT/4ort *ypasse$ orLoopba"# 6o$e
TN TN9
TN TN9
Opti"al 8iber
36!D36! +le"tri"al Cable
*egend
,N ,N9
,N ,N9
Figure 4 Optical Test etup
I9*+,T
=UT/4ort *ypasse$ orLoopba"# 6o$e
TN
TN
Opti"al 8iber
36!D36! +le"tri"al Cable
*egend
,N
,N
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Appendi B: Test "atterns
#eferences
E1F 63J ; Table !: !11: !15
E2F 63J3 ; Cla&se 12: 15
8or 17(8C $evi"es: patterns &se$ are $efine$ by Cla&se of 8C963J3 4(8C an$ (8C patterns &se$ are as
follows)
Table 1 9 CT!T /T!T in a 8C "ompliant frame format
Table 2 9 C,!T /,!T in a 8C "ompliant frame format
Table 5 9 C3!T /3!T in a 8C "ompliant frame format
8ibre Channel Consorti&m 15 8C9I9' *it +rror ,ate Test 3&ite v10
Primitive Count
(Idle) BC 95 B5 B5 6
(SOFn3) BC B5 36 36 1
BE D7 23 47
166B 8F B3 14
5E FB 35 59
(CRC) EE 23 55 16 1
BC B5 D5 D5 1(EOFn)
Primitive Count
(Idle) BC 95 B5 B5 6
(SOFn3) BC B5 36 36 1
7E 7E 7E 7E 41
7E 7E 7E 74 1
7E AB B5 B5 1
B5 B5 B5 B5 12
B5 5E 4A 7E 1
7E 7E 7E FE 1
(CRC) F5 2E F6 DD 1
BC B5 D5 D5 1(EOFn)
Primitive Count
(Idle) BC 95 B5 B5 6
(SOFn3) BC B5 36 36 1
7F 7F 7F 7F 512(CRC) F1 96 DB 97 1
BC 95 D5 D5 1(EOFn)
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8ibre Channel Consorti&m 14 8C9I9' *it +rror ,ate Test 3&ite v10
Figure 5 67T 2scram(led 8itter pattern3 94:
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8ibre Channel Consorti&m 1' 8C9I9' *it +rror ,ate Test 3&ite v10
Figure ; 6T7T 26itter tolerance scram(led pattern3 94:
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Appendi C: Bit Error Rate Measurement
urpose To $evelop a pro"e$&re for bit error rate meas&rement thro&%h the appli"ation of statisti"al metho$s
#eferences
E1F 6iller: Irwin an$ ohn + 8re&n$: robability an$ 3tatisti"s for +n%ineers /3e"on$ +$ition: renti"e9Hall:
1--: pp 149210: 240924'
*ast +odification November 4: 2004 /
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b k ;n , p=Cn , kpk
1p
nk /+&ation *91
Note that in this "ase: a s&""essf&l o&t"ome is a bit error The "oeffi"ient Cn:#
is referre$ to as the binomial
"oeffi"ient or ?n9"hoose9#@ It is the n&mber of "ombinations of # s&""esses in n trials ,et&rnin% to "oin toss
analo%y: there are 5 ways to %et 2 hea$s from 5 "oin tosses) /tails: hea$s: hea$s: /hea$s: tails: hea$s: an$ /hea$s:
hea$s: tails Therefore: C5:2
wo&l$ be 5 ! more pre"ise mathemati"al $efinition is %iven in e&ation *92
cn , k= n !
k ! nk !/+&ation *92
This mo$el refle"ts the fa"t that for a %iven probability: p: a test in whi"h n bits are sent "o&l$ yiel$ manypossible o&t"omes However: some o&t"omes are more li#ely than others an$ this li#elihoo$ prin"iple allows &s to
ma#e "on"l&sions abo&t the *+, for a %iven test res<
*5 ; Hypothesis Test
The statisti"al metho$ of hypothesis testin% will allow &s to establish a val&e of n: the n&mber of bits to be sent:
for the *+, meas&rement Nat&rally: the test be%ins with a hypothesis In this "ase: we will hypothesiAe that theprobability of a bit error: p: for the system is less than some tar%et *+,:
0 This hypothesis is state$ formally in
e&ation *95
H0: pP0 /+&ation *95
Ge now "onstr&"t a test for this hypothesis In this "ase: we will ta#e the obvio&s approa"h of sen$in% n bits
an$ "o&ntin% the n&mber errors: # Ge will interpret the test res<s as shown in table *91
Table *91) !""eptan"e an$ reKe"tions re%ions for H0
Test #esult Conclusion
# Q 0 H0is tr&e
# R 0 H0is false
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Ge now a"#nowle$%e the possibility that o&r "on"l&sion is in error 3tatisti"ians $efine two $ifferent "ate%oriesof error ! type I error is ma$e when the hypothesis is reKe"te$ even tho&%h it is tr&e ! type II error is ma$e when
the hypothesis is a""epte$ even tho&%h it is false The probability of a type I an$ a type II error are $enote$ as aan$
brespe"tively Table *92 $efines type I an$ type II errors in the "ontet of this test
Table *92) =efinitions of type I an$ type II errors
Type ! 0rror # R 0 even tho&%h p *+,
Type !! 0rror # Q 0 even tho&%h p R *+,
! type II error is ar%&ably more serio&s an$ we will $efine n so that the probability of a type II error: b: is
a""eptable The probability of a type II error is %iven in e&ation *94
=1pn1P0n
/+&ation *94
+&ation *94 ill&strates that the &pper bo&n$ on the probability of a type II error is a f&n"tion of the tar%et bit
error rate an$ n *y solvin% this e&ation for n: we "an $etermine the minim&m n&mber of bits that nee$ to sent in
or$er to verify that p is less than a %iven 0for a %iven probability of type II error
nln
ln1P0/+&ation *9'
Let &s now eamine the probability of a type I error The $efinition of ais %iven in e&ation *97
=11pn11P0n
/+&ation *97
+&ation *97 shows that while we in"rease n to ma#e bsmall: we sim<aneo&sly raise the &pper bo&n$ on a
This ma#es sense sin"e the li#elihoo$ of observin% a bit error in"reases with the n&mber of bits that yo& sen$: nomatter how small bit error rate is Therefore: while the hypothesis test is very &sef&l in $eterminin% a reasonable
val&e for n: we m&st be very "aref&l in interpretin% the res<s 3pe"ifi"ally: if we sen$ n bits an$ observe no errors:
we are "onfi$ent that p is less than o&r tar%et bit error rate /o&r level of "onfi$en"e $epen$s on how small we ma$e
b However: if we $o observe bit errors: we "annot be &i"# to ass&me that the system $i$ not meet the *+, tar%et
sin"e the probability of a type I error is so lar%e In the "ase of # R 0: a "onfi$en"e interval "an be &se$ to help &s
interpret #
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*4 ; Confi$en"e Interval
The statisti"al metho$ of "onfi$en"e intervals will be &se$ to establish a lower bo&n$ on the bit error rate %iven
that # R 0 ! "onfi$en"e interval is a ran%e of val&es that is li#ely to "ontain the a"t&al val&e of some parameter of
interest The interval is $erive$ from the meas&re$ val&e of the parameter: referre$ to as the point estimate: an$ the
"onfi$en"e level: /19a: the probability that the parameter>s a"t&al val&e lies within the interval
! "onfi$en"e interval re&ires a statisti"al mo$el of the parameter to be bo&n$e$ In this "ase: we &se thestatisti"al mo$el for # %iven in e&ation *91 If we were to "omp&te the area &n$er the binomial "&rve for some
interval: we wo&l$ be "omp&tin% the probability that # lies within that interval This "on"ept is shown in fi%&re *91
8i%&re *91) Comp&tin% the probability that A 9174' /stan$ar$ normal $istrib&tion
To "omp&te the area &n$er the binomial "&rve: we nee$ a val&e for the parameter p To "omp&te a "onfi$en"e
interval for #: yo& ass&me that #Dn: the point estimate for p: is the a"t&al val&e of p
Note that fi%&re *91 ill&strates the "omp&tation of the lower toleran"e bo&n$ for #: a spe"ial "ase where the
"onfi$en"e interval is E#l: F ! lower toleran"e bo&n$ implies that in a per"enta%e of f&t&re tests: the val&e of #
will be %reater than #l In other wor$s: a"t&al val&e of # is %reater than #
lwith probability e&al to the "onfi$en"e
level Therefore: if #lDn is %reater than
0: we "an say that the system $oes not meet the tar%et bit error rate with
probability /19a *y re$&"in% a: we re$&"e the probability of ma#in% a type I error
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To $etermine the val&e of #l: it is &sef&l to ass&me that the binomial $istrib&tion "an be approimate$ by a
normal /(a&ssian $istrib&tion when n is lar%e The mean an$ varian"e of this e&ivalent $istrib&tion are the mean
an$ varian"e of the "orrespon$in% binomial $istrib&tion /%iven in e&ations *9- an$ *9
k=np /+&ation *9-
k2=np1p /+&ation *9
Now: let abe the probability that S Aawhere S is a stan$ar$ normal ran$om variable ! stan$ar$ ran$om
variable is one whose mean is Aero an$ whose varian"e is one The ran$om variable "an be stan$ar$iAe$ as shown
in e&ation *9
Z=K k k
/+&ation *9
Note that S is %reater than Aawith probability /19a: the "onfi$en"e level Ge apply this ine&ality to e&ation
*9 an$ solve for to %et e&ation *910
K kz k
Knpznp 1p
/+&ation *910
!s mentione$ before: we ass&me that p is #Dn Ge "an now %enerate an epression for #l: the val&e that will
e"ee$ with probability /19a This epression is %iven in e&ation *911
kl=kznk/ n1k/n
n/+&ation *911
8inally: we ar%&e that if e"ee$s #l: then the a"t&al val&e of p m&st e"ee$ #lDn Therefore: we "an %enerate
an epression for pl: the val&e that p will e"ee$ with probability /19a: an$ "ompare it to the tar%et bit error rate *y
applyin% this "omparison /%iven in e&ation *912 the probability of a type I error "an be %reatly re$&"e$ 8or
eample: by settin% Aa
to ;174': the probability of a type I error is re$&"e$ to '
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P0pl=kln=
k
nz
k/n1k/n
n/+&ation *912
*' ; 3ample Test Constr&"tion
Ge now "ompress the theory presente$ in se"tions *92 thro&%h *94 into two ine&alities that may be &se$ to
"onstr&"t a bit error rate test 8irst: we ta#e e&ation *9' an$ ass&me that ln/1-0 is ;
0/vali$ for
0m&"h less
than one The res< is e&ation *915
nln
P0/+&ation *915
3e"on$: we eamine e&ation *912 !ss&min% that /19#Dn is very "lose to 1 an$ s&bstit&tin% ;ln/bD0for n: we
%et e&ation *914
lnkzk /+&ation *914
The lar%est val&e of # that satisfies e&ation *914 is #l The benefit of these two e&ations is that a bit error rate
test is &ni&ely $efine$ by ban$ a an$ that the test s"ales with 0 Table *95 $efines n an$ #
lin terms of ban$ a.
Table *95) n an$ #las a f&n"tion of ban$ a
< -ln2
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(iven that a ' "han"e of a type II error is a""eptable: we fin$ that #lis - If more than - errors are "o&nte$: we
are "onfi$ent that the bit error rate is %reater than 10912 However: what if between 1 an$ - errors are "o&nte$P These
"ases may be han$le$ several $ifferent ways One option is to ma#e a statement abo&t the bit error rate /whether it isless than or %reater than 10912 at a lower level of "onfi$en"e !nother option wo&l$ be to state that the test res< is
s&""ess sin"e we "annot establish with an a""eptable probability of error that the *+, is %reater than 10912 3&"h a
statement implies that we faile$ to meet the b&r$en of proof for the "onKe"t&re that the *+, e"ee$ 10912 Of "o&rse:
the b&r$en of proof "o&l$ be shifte$ to the $evi"e &n$er test whi"h wo&l$ imply that any o&t"ome other than # Q 0
wo&l$ "orrespon$ to fail&re /the $evi"e &n$er test faile$ to prove to &s that the *+, was no more than 10 912 Ifneither of these sol&tions are a""eptable: it is always an option to perform a more vi%oro&s bit error rate test in or$er
to "larify the res<
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