ISO/IEC 17568:2013
(Main)Information technology — Telecommunications and information exchange between systems — Close proximity electric induction wireless communications
Information technology — Telecommunications and information exchange between systems — Close proximity electric induction wireless communications
ISO/IEC 17568:2012 specifies a connection layer (CNL) and a physical layer (PHY) for transferring data between two close proximity entities using electric induction coupling.
Technologies de l'information — Téléinformatique — Communications sans fil à induction électrique de proximité rapprochée
General Information
Standards Content (Sample)
INTERNATIONAL ISO/IEC
STANDARD 17568
First edition
2013-03-01
Information technology —
Telecommunications and information
exchange between systems — Close
proximity electric induction wireless
communications
Technologies de l'information — Téléinformatique — Communications
sans fil à induction électrique de proximité rapprochée
Reference number
©
ISO/IEC 2013
© ISO/IEC 2013
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any
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Published in Switzerland
ii © ISO/IEC 2013 – All rights reserved
Contents Page
Foreword .vi
Introduction.vii
1 Scope.1
2 Conformance .1
3 Normative references.1
4 Terms and definitions .1
5 Abbreviations and acronyms .2
6 Overview.3
6.1 Introduction.3
7 Transmit signal .4
7.1 Modulation scheme parameters .4
7.2 Transmitter functional block diagram .4
7.2.1 Supported Rate Settings and rate dependent parameters.5
7.2.2 Reed-Solomon encoder .6
7.2.3 Convolutional encoder.7
7.2.4 ECS .8
7.2.5 Spreader .9
7.2.6 Sync sequence .9
7.2.7 Scrambler .10
7.2.8 Scrambling sequence generator.11
7.2.9 Pi/2 shift BPSK mapper.12
7.2.10 Mathematical framework of the Up Converter and the Baseband Waveform Generator.13
7.2.11 Baseband waveform.13
7.3 Frame format.14
7.3.1 PPDU format .14
7.3.2 PHY Header format.15
7.4 Transmitter.17
7.4.1 Measurement points.17
7.4.2 Transmit frequency .17
7.4.3 Transmit clock rate requirement.17
7.4.4 Transmit Constellation Error (EVM) .17
8 Receiver.17
8.1 Measurement point.17
8.2 Reference sensitivity.17
8.3 Blocking.17
9 Electric Induction Field.18
10 CNL service definition.19
10.1 Overview of CNL services .19
10.1.1 Connection control service .19
10.1.2 Data service .19
10.1.3 Security service .19
10.2 CNL service access point.19
10.2.1 Initialize.22
10.2.2 Close.22
10.2.3 Connect and accept .22
10.2.4 Connection release .24
10.2.5 Power save.25
© ISO/IEC 2013 – All rights reserved iii
10.2.6 Data transfer.26
10.3 CPDU formats.27
10.3.1 Conventions .27
10.3.2 Acknowledgement (ACK) CPDU.28
10.3.3 CNL data CPDUs.32
10.3.4 Management CPDUs (Link control message) .34
10.4 CNL function description.42
10.4.1 Segmenting/Reassembling.42
10.4.2 Medium state sensing .43
10.4.3 CNL-Level acknowledgements.43
10.4.4 Interframe space (IFS) .48
10.4.5 Access procedure.49
10.4.6 Multirate support.51
10.4.7 UID filter .51
10.5 CNL state .51
10.5.1 Close state.52
10.5.2 Search state.52
10.5.3 Connection request state.53
10.5.4 Accept waiting state .53
10.5.5 Response waiting state.53
10.5.6 Responder response state.54
10.5.7 Initiator connected state .54
10.5.8 Responder connected state.54
10.5.9 Sub-states within the Initiator connected state or Responder connected state.55
10.6 Numerical parameters .57
Annex A (normative) UID Specification .59
A.1 UID Composition.59
A.1.1 Specifier ID .59
A.1.2 Reserved.59
A.1.3 Extension Identifier.59
Annex B (informative) Coupler.60
Annex C (informative) Coupler measurement .61
Annex D (informative) Reference Coupler .63
Annex E (informative) Sample Data Sequences.65
E.1 Reed-Solomon Encoder .65
E.2 Convolutional Encoder .65
E.3 PHY Header HCS.67
E.4 Common CNL Header HCS.67
E.5 Sub CNL Header HCS.67
E.6 Scrambling sequence generator.67
Annex F (informative) CNL frame exchange sequences.70
F.1 CNL frame exchange sequences .70
F.1.1 Connection setup procedure.70
F.1.2 CSDU exchange procedure .70
F.1.3 Connection sleep procedure .71
F.1.4 Connection wakeup procedure .72
F.1.5 Connection confirmation procedure.73
F.1.6 Connection release procedure.73
Annex G (informative) CNL service operation.74
G.1 Initialize operation .74
G.2 Close operation.74
G.3 Connect request.75
G.3.1 Connect request operation .75
G.3.2 Accept receive operation .75
G.3.3 Accept response operation .76
G.3.4 Connect release operation.76
iv © ISO/IEC 2013 – All rights reserved
G.3.5 Accept release operation.76
G.4 Connect accept.77
G.4.1 Request receive operation.77
G.4.2 Accept request operation .77
G.4.3 Accept acknowledge operation .78
G.4.4 Accept release operation.78
G.4.5 Connect release operation .79
G.4.6 Request crossover operation.79
G.4.7 Accept request operation .80
G.4.8 Accept release operation.80
G.5 Release .81
G.5.1 Release request receive operation .81
G.5.2 Release receive operation .81
G.6 Transfer data.82
G.6.1 Data send operation .82
G.6.2 Data receive operation.83
G.6.3 Resend timeout operation .84
G.6.4 Target wake operation .85
G.7 Power save.86
G.7.1 Power save request operation .86
G.7.2 Sleep receive operation .87
G.8 Wakeup.88
G.8.1 Wakeup request operation .88
G.8.2 Wakeup acknowledge operation.88
G.8.3 Wakeup receive operation.89
G.8.4 Data send request operation.89
G.8.5 Wakeup data send operation .89
G.8.6 Wakeup timeout operation .90
G.9 Probe.90
G.9.1 Probe send operation.91
G.10 Probe ACK receive operation.91
G.10.1 Probe receive operation.91
G.10.2 Probe timeout operation.92
© ISO/IEC 2013 – All rights reserved v
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees
established by the respective organization to deal with particular fields of technical activity. ISO and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information
technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as
an International Standard requires approval by at least 75 % of the national bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
ISO/IEC 17568 was prepared by Ecma International (as ECMA-398) and was adopted, under a special “fast-
track procedure”, by Joint Technical Committee ISO/IEC JTC 1, Information technology, in parallel with its
approval by national bodies of ISO and IEC.
vi © ISO/IEC 2013 – All rights reserved
Introduction
Today’s typical consumer uses digital files to store multimedia content such as music, photos, and videos. But
these files are quickly becoming larger in number and size. A continual demand for higher quality results in
larger file sizes. And proliferation of smaller, portable devices makes it easier to generate more content in less
time. But the desire to store, share, and enjoy that content remains strong. And this usually requires
transferring the content from one device to another. For example, storing might involve transferring the
content from a video camera to an external disk drive. Sharing photos might involve transferring the contents
from one mobile phone to another mobile phone. And enjoying content might involve streaming content from a
video camera to a TV using a special video cable.
But with today’s available technology, these activities present difficulties to the average consumer. The
transfer process may take a long time due to the large file sizes. Or it may involve special cables or complex
setup. Therefore, a need exists to make it faster and simpler to transfer large multimedia files. This
International Standard specifies a technology that addresses this need by using close proximity electric
induction to transfer large files quickly and easily.
© ISO/IEC 2013 – All rights reserved vii
INTERNATIONAL STANDARD ISO/IEC 17568:2013(E)
Information technology — Telecommunications and information
exchange between systems — Close proximity electric
induction wireless communications
1 Scope
This International Standard specifies a connection layer (CNL) and a physical layer (PHY) for transferring data
between two close proximity entities using electric induction coupling.
2 Conformance
Implementations conforming to this International Standard implement both the CNL and the PHY. All
Conforming implementations support a centre frequency of 4,48 GHz and all rate settings specified in Table 2.
3 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO/IEC 7498-1:1994, Information technology — Open System Interconnection — Basic Reference Model:
The Basic Model
ITU-T Z.120, Series Z: Languages and General Software Aspects for Telecommunication Systems, Formal
description techniques (FDT) – Message Sequence Chart (MSC)
4 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
4.1
chip
shortest duration digital unit that is transmitted and used to spread the spectrum
4.2
chip rate
rate at which chips are transmitted
4.3
coupler
antenna used to transmit and receive an electric induction field
4.4
electric induction field
electric field with strength inversely proportional to the distance squared
© ISO/IEC 2013 – All rights reserved 1
4.5
initiator
sender of a connection request
4.6
PHY rate
chip rate / spreading factor
4.7
responder
receiver of a connection request
4.8
spreading factor
number of duplications
4.9
symbol
modulation pulse in a single I or Q channel as expressed as a baseband waveform
4.10
symbol rate
rate at which symbols are transmitted in each I or Q channel
4.11
target
peer entity
4.12
unique ID
code uniquely identifying each implemented unit
5 Abbreviations and acronyms
ACK Acknowledgement
BPSK Binary Phase Shift Keying
CCF Convolutional Coding Factor
CNL CoNnection Layer
CPCI CNL Protocol Control Information
CPDU Connection layer Protocol Data Unit
CSDU Connection layer Service Data Unit
C-Acc “Connection Accept” message management frame
C-Probe “Connection Probe” message management frame
C-Req “Connection Request” message management frame
C-Rls “Connection Release” message management frame
C-Sleep “Connection Sleep” message management frame
C-Wake “Connection Wakeup” message management frame
ECS Error Check Sequence
EVM Error Vector Magnitude
FCS Frame Check Sequence
FEC Forward Error Collection
HCS Header Check Sequence
ImACK Immediate Acknowledgement required
LFSR Linear Feed-back Shift Register
LiCC Link Control Command
MSC Message Sequence Chart
MUX Multiplexer
NoACK No Acknowledgement required
2 © ISO/IEC 2013 – All rights reserved
PDU Protocol Data Unit
PHY Physical Layer
PPCI PHY Protocol Control Information
PPDU Phy layer Protocol Data Unit
PSD Power Spectral Density
PSDU PHY SDU
SAP Service Access Point
SDU Service Data Unit
UID Unique ID
6 Overview
6.1 Introduction
This International Standard specifies the bottom 2 layers of a close proximity wireless transfer technology. By
touching (or bringing very close together) two electronic entities, this technology allows high speed exchange
of data. The basic concept consists of a touch-activated multi-purpose interface designed for applications
requiring high-speed data transfer between two entities in a point-to-point (1:1) mode, without the need for
external physical connectors.
The physical layer has a maximum transmission rate of 560 Mbps, adjusting the data rate downward
according to the wireless environment to maintain a robust link even when the surrounding wireless condition
fluctuates.
The RF transmit power is kept at a very low level to cause negligible interference with other nearby wireless
systems, including other close proximity electric induction systems.
Implementations transmit and receive by means of an electric induction field suitable for near field data
exchange. This approach is fundamentally different from traditional wireless systems using microwave
radiation.
Entities establish a link to enable data transfer and serve as initiator and responder respectively. These two
roles have no relation to the actual direction of data transfer as illustrated in Figure 1.
Close Proximity
Data
Electric Induction
InInInInitiaitiaitiaitiatotototorrrr
Wireless
RRRReeeesponsponsponspondededederrrr
Communication Data
Figure 1 — Connection between Initiator and Responder
The initiator sends a “connection request”, and the responder is its peer that receives a “connection request”.
Entities can assume either of these roles.
As specified in Figure 2, this International Standard uses the OSI Basic Reference Model specified in
ISO/IEC 7498-1.
© ISO/IEC 2013 – All rights reserved 3
Figure 2 — OSI Basic Reference Model used in this International Standard
7 Transmit signal
7.1 Modulation scheme parameters
The modulation scheme uses Pi/2 shift BPSK and a chip rate (R ) of 560 Mcps, as illustrated in Table 1. Here,
c
the chip rate refers to the shortest duration digital units that are transferred over the air as well as the digital
bits that are used to spread the transmitted bandwidth. Since the modulation scheme uses Pi/2 shift BPSK,
the reciprocal number of the chip rate (1/R ) represents the interval between samples of an envelope
c
concatenated along the time axis and the symbol rate (R ) on one channel (Ich or Qch) is half the occupied
s
bandwidth (R ) of the envelope. Hence, the relationship of R = R /2 is established.
c s c
Table 1 — Tx signal parameters
Chip Rate: R 560 Mcps
c
Chip duration: Tc = 1/R 1,786 nsec
c
Symbol Rate: R 280 Msps
s
Carrier Center Frequency: F 4,48 GHz
c
Modulation Pi/2 shift BPSK + DSSS
FEC 1/2 Convolutional code + Reed Solomon code
7.2 Transmitter functional block diagram
The transmitter functional block diagram is illustrated in Figure 3. Data from the CNL is first encoded by the
Reed-Solomon encoder and the Convolutional encoder. Whether the Convolutional encoder is on or off is
determined by the Rate Setting in use, as defined in Table 2.
4 © ISO/IEC 2013 – All rights reserved
The spreader spreads the encoded data by duplicating symbols by the spreading factor or process gain G .
SF
The spread data is then scrambled by the scrambler. Scrambling is accomplished using a pseudo random
sequence generated by the Linear Feedback Shift Register (LFSR) in the Scrambler Sequence Generator. Of
the fields of the frame format specified in Figure 14, the Preamble, PHY Header and Payload are scrambled
using different random seeds.
The Pi/2 shift BPSK mapper spreads a binary sequence into complex number signals by multiplying the input
signal by a rotator whose rotation angle differs by 90 degrees for each sample.
The baseband waveform generator illustrated in Figure 3 is a filter that uses the baseband waveform specified
in Figure 12 as the impulse response. The generated baseband signal S (t) is then up-converted to centre
BB
frequency F by the RF module.
c
Figure 3 — Transmitter functional block diagram
7.2.1 Supported Rate Settings and rate dependent parameters
Table 2 specifies the rates used by the PHY. For rate control, the PHY manipulates the following parameters:
• Spreading factor (G ) = 1, 2, 4, 8, or 16
SF
• Convolutional code factor (G ):
CC
o G = ½ if Convolutional code is used
CC
o G = 1 otherwise
CC
• Reed-Solomon Factor (G ):
RS
o G = 224/240 if Reed-Solomon coding is used
RS
o G = 1 otherwise
RS
From the above parameters, the rates are calculated as follows.
• Chip Rate = 560 Mcps
• Symbol Rate = 280 Msps
© ISO/IEC 2013 – All rights reserved 5
• PHY Rate (Mbps) = Chip Rate (Mcps) / G
SF
• Data Rate (Mbps) = PHY Rate (Mbps) x CCF x G
RS
Table 2 — Rates (Data Rate is rounded down to the nearest 1 Mbps)
Rate Chip Symbol PHY Data Spreading Convolutional Reed-
Settings Rate Rate Rate Rate Factor: Code Used? Solomon
(Mcps) (Msps) (Mbps) (Mbps) G Code
SF
Used?
Rate 522 560 280 560 522 1 No Yes
Rate 261 560 280 560 261 1 Yes Yes
Rate 130 560 280 280 130 2 Yes Yes
Rate 65 560 280 140 65 4 Yes Yes
Rate 32 560 280 70 32 8 Yes Yes
PHY 560 280 35 17 16 Yes No
Header
7.2.2 Reed-Solomon encoder
Table 3 specifies the parameters of the Reed-Solomon encoder. Reed-Solomon code is employed for the
CPDU inner coding.
Table 3 — Reed-Solomon encoder parameters
Function Description
Galois field GF (2 )
8 4 3 2
Primitive polynomial p(X) = X +X +X +X + 1
Primitive element MSB LSB
α =[]00000010
Generating polynomial 15
i
g(X) = ()X −α
∏
i=0
Code length 240 Bytes
Data length 224 Bytes
PSDU data shall be Reed-Solomon encoded as follows.
1) Starting with Byte 00 (see Figure 18), each block of 224 bytes shall be transferred to the Reed-
Solomon encoder to generate the 16 parity bytes. The bit-ordering of each byte and each Galois field
symbol shall be identical. Simultaneously, the same 224 bytes shall be transferred unchanged in the
same order to the next stage of processing. These 224 bytes are referred to as message bytes.
2) After each block of message bytes are transferred to the next stage of processing, the 16 bytes of
Reed-Solomon parity shall be transferred to the next stage of processing in the order of MSB first of
each parity byte. The parity bytes shall be transferred starting from higher order to lower order.
6 © ISO/IEC 2013 – All rights reserved
Note that the Reed-Solomon encoder transfers and processes data in byte-by-byte order. See Annex E for
examples of Reed-Solomon Encoder data values.
7.2.3 Convolutional encoder
Table 4 specifies the parameters of the Convolutional encoder. Convolutional code is employed for the PHY
Header and the CPDU outer coding.
Table 4 — Convolutional encoder parameters
Function Description
Constraint length K=3
Polynomial G0=7oct, G1=5oct
Table 5 specifies the relation between the Rate Setting and the number of convolutional encoders.
Figure 4 and Figure 5 specify the input/output relationship for the convolutional encodings. The input signal in
both Figure 4 and Figure 5 is the RS-Encoded data as specified in Figure 14.
Table 5 — Rate Settings and number of convolutional encoders
Rate Setting Num. of Conv. Enc. Input/Output bit ordering
Rate 522 No convolutional code
Rate 261 2 See Figure 4
Rate 130 1 See Figure 5
Rate 65 1 See Figure 5
Rate 32 1 See Figure 5
PHY Header 1 See Figure 5
Figure 4 — Convolutional encoder for Rate 261
© ISO/IEC 2013 – All rights reserved 7
D5
D4
D3
D2
D1
D0
D5 D4
D3 D2
D1 D0
bG12 bG02 aG12 aG02
bG11 bG01 aG11 aG01
bG10 bG00 aG10 aG00
bG11
bG01
aG11
aG01
bG10
bG00
aG10
aG00
Figure 5 — Convolutional encoder for Rate 130 to Rate 32 and PHY Header
Figure 4 and Figure 5 show each storage element as a box labelled Tb where Tb is the bit duration of the
Input data. The storage elements shall have value=0 at t=0. See Annex E for examples of Convolutional
Encoder data values.
In Figure 4 and Figure 5, the data is transferred and processed bit by bit starting with the MSB of S (t).
CI
7.2.4 ECS
Figure 6 and Equation (1) specify the 16-bit ECS. The notation [n2:n1] means sequence of bits ordered from
bit n2 to bit n1 where bit n2 is the most significant bit (MSB) and bit n1 is the least significant bit (LSB).
Figure 6 — 16-bit ECS generator
16-bit ECS calculation:
q [15:0]=0x FFFF
st
In [7:0] is the 1 byte in the ECS target field to be sent.
“^” denotes the XOR (exclusive OR) operator in Equation (1).
q [15] = q [8] ^ q [0] ^ In [0] ^ q [4] ^ In [4]
t+1 t t t t t
q [14] = q [9] ^ q [1] ^ In [1] ^ q [5] ^ In [5]
t+1 t t t t t
q [13] = q [10] ^ q [2] ^ In [2] ^ q [6] ^ In [6]
t+1 t t t t t
q [12] = q [11] ^ q [0] ^ In [0] ^ q [3] ^ In [3] ^ q [7] ^ In [7]
t+1 t t t t t t t
q [11] = q [12] ^ q [1] ^ In [1]
t+1 t t t
8 © ISO/IEC 2013 – All rights reserved
q [10] = q [13] ^ q [2] ^ In [2]
t+1 t t t
q [9] = q [14] ^ q [3] ^ In [3]
t+1 t t t
q [8] = q [15] ^ q [0] ^ In [0] ^ q [4] ^ In [4]
t+1 t t t t t
q [7] = q [0] ^ In [0] ^ q [1] ^ In [1] ^ q [5] ^ In [5]
t+1 t t t t t t
q [6] = q [1] ^ In [1] ^ q [2] ^ In [2] ^ q [6] ^ In [6]
t+1 t t t t t t
q [5] = q [2] ^ In [2] ^ q [3] ^ In [3] ^ q [7] ^ In [7]
t+1 t t t t t t
q [4] = q [3] ^ In [3]
t+1 t t
q [3] = q [0] ^ In [0] ^ q [4] ^ In [4]
t+1 t t t t
q [2] = q [1] ^ In [1] ^ q [5] ^ In [5]
t+1 t t t t
q [1] = q [2] ^ In [2] ^ q [6] ^ In [6]
t+1 t t t t
q [0] = q [3] ^ In [3] ^ q [7] ^ In [7] (1)
t+1 t t t t
See Annex E for examples of 16-bit ECS data values.
7.2.5 Spreader
Figure 7 and Table 6 specify the function of the spreader.
x
f (x)
S (t)
SP
SP
S (t)
CO
G
SF
Figure 7 — Spreader
Table 6 — Input and output relationship of the Spreader
Spreading Factor: G Input: x (a = 1 or 0) Output: S (t)
SF SP
1 a a
2 a a,a
4 a a,a,a,a
8 a a, … ,a : Repeat 8 times
16 a a, … …,a : Repeat 16 times
7.2.6 Sync sequence
Table 7 specifies the Sync sequence, C (t), used for packet synchronization. C (t) consists of 128 chips and
SY SY
expects the transmission to start with the 0th index.
© ISO/IEC 2013 – All rights reserved 9
Table 7 — Sync sequence C (t)
SY
0 1 16 1 32 1 48 0 64 0 80 0 96 0 112 1
1 1 17 0 33 0 49 1 65 1 81 1 97 1 113 0
2 0 18 0 34 1 50 0 66 0 82 1 98 1 114 0
3 1 19 0 35 0 51 0 67 0 83 0 99 0 115 1
4 1 20 1 36 0 52 0 68 1 84 0 100 0 116 0
5 1 21 1 37 1 53 0 69 1 85 0 101 0 117 0
6 1 22 1 38 0 54 1 70 1 86 0 102 1 118 0
7 0 23 1 39 1 55 0 71 0 87 0 103 0 119 0
8 1 24 0 40 1 56 0 72 1 88 1 104 0 120 0
9 1 25 0 41 0 57 1 73 1 89 1 105 0 121 0
10 1 26 0 42 1 58 1 74 0 90 1 106 1 122 1
11 0 27 1 43 0 59 1 75 0 91 0 107 0 123 0
12 0 28 1 44 1 60 1 76 1 92 1 108 0 124 1
13 0 29 0 45 1 61 0 77 1 93 0 109 0 125 1
14 0 30 1 46 1 62 1 78 0 94 1 110 1 126 0
15 1 31 1 47 1 63 1 79 1 95 1 111 0 127 0
7.2.7 Scrambler
Figure 8 specifies the configuration of the scrambler. Table 8 specifies the scrambler truth table which uses an
inverted XOR of the spread signal S (t) and the LFSR-generated signal.
SP
Figure 8 — Scrambler
Table 8 — Truth table of Scrambler
x Y S (t)
SC
0 0 1
0 1 0
1 0 0
1 1 1
10 © ISO/IEC 2013 – All rights reserved
As specified in Table 9 the scrambler uses scrambling sequences C (t), C (t), and C (t) for the Preamble,
PR HE PA
PHY Header, and Payload parts of the transmit packet, respectively. These sequences are generated by the
scrambling sequence generator specified in 7.2.8. Note the Preamble and Sync parts use a constant 1 data
input. Therefore C (t) and C (t) pass through the scrambler unmodified.
PR SY
Table 9 — Input of Scrambler
Part of Packet x Input of f (x,y) y Input of f (x,y)
SC SC
Preamble 1 C (t) = C (t)
SC PR
Sync 1 C (t)
SY
PHY Header S(t) C (t) = C (t)
SP SC HE
Payload S(t) C (t) = C (t)
SP SC PA
7.2.8 Scrambling sequence generator
Figure 9 illustrates the configuration of the LFSR used to generate the scrambling sequence. Equation (2)
specifies the polynomial equation for LFSR generation. Table 10 specifies the relationship between LFSR
seeds and scrambling sequences. The scrambling sequence generator expects the register value to be
initialized by the scrambling seed [17:0] at the beginning of each part of the packet (Preamble, PHY Header,
and Payload).
18 10 7 5
G(x) = x +x +x +x +1 (2)
Figure 9 — Block diagram of Scrambling sequence generator LFSR
Table 10 — Scrambling sequence generator seeds and outputs
Part of Packet Scrambling Seed [17:0] Output of Scrambling
Sequence Generator: C (t)
SC
Preamble 0x011A0 C (t)
PR
Header 0x27BFA C (t)
HE
Payload 0x3C859 C (t)
PA
See Annex E for examples of Scrambling sequences.
© ISO/IEC 2013 – All rights reserved 11
7.2.9 Pi/2 shift BPSK mapper
Figure 10 specifies the configuration of the Pi/2 shift BPSK mapper. The Pi/2 shift BPSK mapper converts an
input binary sequence to a complex output sequence.
Figure 10 — Pi/2 shift BPSK mapper
Figure 11 illustrates the concept of Pi/2 shift BPSK modulation. Pi/2 shift BPSK expects the modulation axis
for BPSK modulation to rotate by 90 degrees for each consecutive symbol. This implementation rotates the
phase by 90 degrees for each new bit or chip from the scrambler. For each 4 chips, the modulation axis is
rotated by a complete 360 degree cycle.
Qch Qch Qch Qch
+ -
- + + -
Ich Ich Ich Ich
- +
Figure 11 — Concept of Pi/2 shift BPSK
Table 11 specifies the input and output relationship of the Pi/2 shift BPSK mapper. The variable “n” represents
a chip number. It can be seen that the values in the "n mod 4" column correspond to a unique phase rotator
value.
Input signal S (t ) indicates the scrambler binary output at time t = n*T . The function (2* S (t )-1) in the
SC n n c SC n
Output of Table 11 specifies the binary (0,1) to real (-1,1) transformation.
After the binary value is converted to a real value, the output sequence S (x) is multiplied by the rotator value
PI
+1, +j, -1, or -j.
Table 11 — Input and output relation of Pi/2 shift BPSK mapper
n mod 4 Rotator Input:S (t) Output:S (x)
SC PI
0 1 S (t) (2*S (t )-1)
SC 0 SC 0
1 j S (t ) j * (2*S (t )-1)
SC 1 SC 1
2 -1 S (t) - (2*S (t )-1)
SC 2 SC 2
3 -j S (t ) - j * (2*S (t )-1)
SC 3 SC 3
12 © ISO/IEC 2013 – All rights reserved
7.2.10 Mathematical framework of the Up Converter and the Baseband Waveform Generator
S (t) =Re()S (t)⋅exp(j2πFt)
(3)
TX BB c
N −1
chip
S (t) =S (t) ⊗ S (t −n ⋅T )
(4)
BB BW ∑ PI c
n=0
Equation (3) specifies the Up Converter. Equation (4) specifies the Baseband Waveform Generator.
In Equation (3), S (t) represents the transmission baseband sequence, which is illustrated in (Figure 13). F
BB c
is the centre frequency, and Re(x) an operation that calculates the real part of a complex number.
In Equation (4), S (t) represents the transmission baseband waveform, S (t) a complex number delta
BW PI
function, N the number of transmit chips in the packet, and ⊗ convolution. Note that S (t) has weight +1,
chip PI
+j, -1, or –j depending on the Pi/2 shift BPSK modulation.
7.2.11 Baseband waveform
Figure 12 specifies a transmission baseband waveform S (t) using discrete values. In Figure 12, one cycle of
BW
the waveform is represented by 8 samples, with the normalized sample numbers shown along the horizontal
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