5- S-CDMA FWA Overview - Ministère de la poste et des ...

S-CDMA Fixed Wireless
Access Overview
Presenter:
Brian Bolon
Director of Marketing
L-3 PrimeWave Communications

S-CDMA Fixed Wireless Access Overview
Overview of S-CDMA
Comparison to Other FWA
Technologies
Applications & Advantages
–Circuit Switched Voice and Data
–Packet Switched Voice & Data
–Internet Access Implementations
–Quality of Service and VoIP

What is S-CDMA
Synchronous
- Code
Division
Multiple
Access
–A Multiple
Access
Technique is a method of
merging multiple data streams into a single
carrier
–Code
Division
is a modern Multiple Access
Technique using PN codes to spread data
–Synchronous
is an improvement to CDMA
which increases capacity and efficiency by
using orthogonal codes

Common FWA Multiple Access Techniques
Fb
TDMA
Fb
FDMA/OFDMA
CDMA
User 1
Cod
e
Frequency
User 1
Guard Band
User 2
Guard Band
User 3
Frequency
Guard Band
User 2
Guard Band
User 3
Fa
Fb
User 1
User 2
Fa
Time
Fa
Time
User 3
• Time Division Multiple
Access
• Divides a channel into
time slices and transfers
different sub-channels
at different times
• (Orthogonal)
Frequency Division
Multiple Access
• Divides a channel
into different subfrequencies
and
transmits subchannels
at
different
frequencies
• Code Division Multiple
Access
• Spreads a sub-channel in
frequency and time, use
multiple PN codes within
same space

Impossible d'afficher l'image. Votre ordinateur
manque peut-être de mémoire pour ouvrir
l'image ou l'image est endommagée. Redémarrez
l'ordinateur, puis ouvrez à nouveau le fichier. Si
le x rouge est toujours affiché, vous devrez peutêtre
supprimer l'image avant de la réinsérer.
Synchronizing the Forward Link in S-CDMA
The basestation adjusts its transmissions so that its signals
arrive at all Subscribers at the same time.
This synchronous timing, if used at the Chip and Symbol
levels, allows all “Codes” to be orthogonal to one another.
Many CDMA systems employ this in the forward link.
S1
S2
Time X & X’
Subscriber
S1
Time Y
S2
Time Y
Basestation
Subscriber

Impossible d'afficher l'image. Votre ordinateur
manque peut-être de mémoire pour ouvrir
l'image ou l'image est endommagée. Redémarrez
l'ordinateur, puis ouvrez à nouveau le fichier. Si
le x rouge est toujours affiché, vous devrez peutêtre
supprimer l'image avant de la réinsérer.
Synchronizing the Reverse Link in S-CDMA
Timing delay information is fed back from the basestation to
each subscriber.
All subscribers adjust their transmissions so that their
signals arrive at the basestation at the same time.
Few systems employ this in the reverse link.
S1
S2
time
Subscriber
S1
time
S2
time
Basestation
Subscriber

S-CDMA Permits Orthogonal PN Codes
By synchronizing at the chip and
symbol level, , it is possible to use
orthogonal spreading codes.
# of spreading codes per carrier
= “Processing Gain”
Code #1
Orthogonality allows for the
elimination of interference thus
the capacity limitation is # of PN
codes (optimal)
Code #2
L-3 PrimeWave’s PW-2000
2000 has
128 codes per 3.5 MHz carrier in
128 dimensional space
Code #3

So What does S-CDMA do for me
S-CDMA is chip and symbol synchronous using orthogonal spreading
codes and offering code-limited performance.
– S-CDMA offers high fade margins and availabilities far higher than
competing approaches
– S-CDMA offers peak rates and system capacities that are among the best
of competing approaches
– With lower frequency reuse, S-CDMA offers a better spectral efficiency than
other approaches
– S-CDMA provides higher range cells than TDMA due to the ability to trade
range for high data rates.
– Equalization and diversity techniques allow S-CDMA to perform as well or
better in multipath environments than any other approach (including OFDM)
– S-CDMA is more robust to jamming than non-spread spectrum competing
technologies.

S-CDMA Fixed Wireless Access Overview
Overview of S-CDMA
Comparison to Other FWA
Technologies
Applications & Advantages
–Circuit Switched Voice and Data
–Packet Switched Voice & Data
–Internet Access Implementations
–Quality of Service and VoIP

Common FWA Multiple Access Techniques
Fb
TDMA
Fb
FDMA/OFDMA
CDMA
User 1
Cod
e
Frequency
User 1
Guard Band
User 2
Guard Band
User 3
Frequency
Guard Band
User 2
Guard Band
User 3
Fa
Fb
User 1
User 2
Fa
Time
Fa
Time
User 3
• Data bursted at peak
system rate
• Time-slot aggregation
and/or increased slot
duration for increased
throughput
• Low data rates in
each frequency bin
• Frequency bin
aggregation and/or
increased bin size
for increased
throughput
• Low to moderate data
rates in each CDMA
channel
• CDMA channel
aggregation for increased
rate or reduced spreading
factor for increased
throughput

Orthogonal Multiplexing Schemes
Orthogonal Frequency Division Multiplexing (OFDM)
Total Data Rate = 4.096 Mbps
• Carrier aggregation
for high rate support.
32 kbps 32 kbps 32 kbps 32 kbps
f 1 f 2
f 127
f 128
Frequency
Total RF Bandwidth = 3.5 MHz
Orthogonal Code Division Multiplexing (OCDM)
c 128
Orthogonal
Spreading
Codes
c 2
c 1
Total Data Rate = 4.096 Mbps
32 kbps
32 kbps
32 kbps
f c
Total RF Bandwidth = 3.5 MHz
• Spreading Code
aggregation for high
rate support.
• Multi-code CDMA
• Multiple, robust
lower rate channels.
Frequency

Range vs Throughput (Assuming The Same Tx Amplifier)
TDMA range is limited by the burst rate
(true for either single-carrier or OFDM-based TDMA systems)
4 Mbps
4 Mbps
CDMA can trade range for rate in the reverse link
4 Mbps
4 Mbps
2 Mbps
512 kbps
32 kbps

Reverse Link Capacity and Margin: A-CDMA vs. S-CDMA
Spreading Factor = 128
E b /N 0 = 20 dB
40
35
S-CDMA:
Orthogonal Codes
with 40 dB of in-sector
code isolation
Reverse Link SNR (dB)
A-CDMA:
15
Non-orthogonal Codes
with 10 log10(128) = 21 dB
10
of in-sector code isolation
30
25
20
5
0
Eb/Io (S-CDMA)
Eb/No
Eb/Io (A-CDMA)
Eb/(Io+No) (A-CDMA)
Eb/(Io+No) (S-CDMA)
Margin against Fading,
Jamming and Adjacent
Cell/sector interference
Typical threshold for
QPSK and BER

Synchronous vs. Asynchronous CDMA
140
120
100
80
Number of Supported Channels per Sector
(Processing Gain 128)
60
40
20
0
Code Limited Region
Asynchronous
CDMA
Synchronous
CDMA
Interference
Limited
Region
0 2 4 6 8 10 12 14
Spreading Factor
Of 128
chips/symbol
Fade Margin (dB)
Asynchronous CDMA is always
interference limited and non-orthogonal
codes mean higher interference & lower capacity

Wire-line Quality Links Possible w/ S-CDMA
Synchronous CDMA permits
– Code-limited performance (high capacity)
– High fade margins and availability
– Wire-line quality service
– Ability to trade data rate for range
Availability (%)
90
99
99.9
99.99
Fading Channel's
Rice Factor
k = 5
k = 7.5
k = 10
0 5 10 15 20 25 30
Fade Margin (dB)
Number of Supported Channels per Sector
(Processing Gain 128)
140
120
100
80
60
40
20
Asynchronous
CDMA
0
0 2 4 6 8 10 12 14
Fade Margin (dB)
Synchronous
CDMA

Measuring Spectral Efficiency with S-CDMA
Spectral Efficiency – Per CDMA channel:
– CDMA Data Rate / Spread Bandwidth
– Typically low
– E.g. 32 kbps / 3.5 MHz = 0.0091 bps/Hz
Spectral Efficiency – Per SU Aggregate Channel:
– SU Aggregate Data Rate / Spread Bandwidth
– Low to moderate depending on modulation and channel aggregation
– E.g. 256 kbps / 3.5 MHz = 0.073 bps/Hz
Spectral Efficiency – Isolated Cell:
– Cell Capacity / Spread Bandwidth
– Comparable to Single-carrier and multi-carrier TDMA approaches
– E.g. 4.096 Mbps / 3.5 MHz = 1.1703 bps/Hz
Spectral Efficiency – Multi-cell/multi
cell/multi-sector:
– Total System Capacity / Total Required RF Bandwidth / Number of Cells
– Much better than single-carrier and multi-carrier TDMA approaches
– E.g. 4.096 / 3.5 = 1.1702 bps/Hz/cell (multi-cell, single-sector, sector, reuse =1)
– E.g. 4.096 * 4 / (3.5 * 2) = 2.3406 bps/Hz/cell (multi-cell, four-sector, reuse=2)

Spectral Efficiency: S-CDMA vs. TDMA
System
Spectral
Efficiency
=
Total System Capacity (bps)
Required RF Bandwidth (Hz) × #Cells
Code-limited S-CDMA
Assuming No Guard Time,
Pilots or Cyclic Preamble
Spectral Efficiency
S-CDMA
QPSK 16-QAM 64-QAM
TDMA (OFDM or Single Carrier)
Freq.
Reuse QPSK 16-QAM 64-QAM
Freq.
Reuse
Waveform
(bits/sym) 2 4 6 NA 2 4 6 NA
Single Cell (bps/Hz) 2 4 6 NA 2 4 6 NA
Multi-cell w/ 1
sector (bps/Hz/Cell) 2 4 6 1 0.5 1 2 4
Multi-cell w/ 4
sector (bps/Hz/Cell) 4 8 12 2 0.8 1.6 2.4 5
* Suppose a 1M baud rate occupying an RF bandwidth of 1 MHz

PrimeWave 2000 vs. other technologies
Prime Wave 2000
IS-95
GSM
Other Synch CDMAs
Core Technology Synch CDMA Async CDMA TDMA Synch CDMA
Frequency (MHz) 2100, 2200, 2600, 3500 800/1900 800/900/1800/1900 1300 - 3600
Services POTS, Data, ISDN POTS POTS, Limited Data POTS, Data, ISDN
RF Bandwidth 3.5 MHz 1.25 MHz 200 KHz 3.5 MHz
Users/Carriers 100(128) @ 32 kb/s 45 4/8 52
Spectral Efficiency
(Bits/Sec/Hz)
1.2 0.4 .13 (4x3 Freq Reuse) 0.68
Bit Error Rate @ Cap. 10 -6 to 10
-9
Voice Coding Rate 32 and 64 Kbps 8/13 Kbps 4.8/13 Kbps 32 - 64 Kb/s ADPCM
Voice Coding Type ADPCM and None QCELP ADPCM and None
Voice Quality Score Wireline 2.7 Wireline
Digital Data Rate 64, 128, and 256 Kbps 9.6 Kbps 32/64/512 Kbps
Analog Modem Rate 56 Kbps 9.6 9.6 Kbps 56 Kbps

S-CDMA Fixed Wireless Access Overview
Overview of S-CDMA
Comparison to Other FWA
Technologies
Applications & Advantages
–Circuit Switched Voice and Data
–Packet Switched Voice & Data
–Internet Access Implementations
–Quality of Service and VoIP

Circuit-Switching Versus Packet-Switching
Competitor's paradigm:
– Carry both packet and circuit-oriented services over packet switched
physical layer
OR
– Carry both packet and circuit-oriented services over a circuit-switched
physical layer
PrimeWave's paradigm:
– Use a physical layer that has both circuit switched S-CDMA channels and
packet switched S-CDMA channels
– Provide each service with unique S-CDMA channels having the desired
latency, jitter and bit error rate
Providing circuit-switched services on a purely packet-switched
physical layer leads to lower quality
PrimeWave's circuit-switching quality will be maintained in the future

Circuit-Switched Telephony Application
Analog
Phones
Fax
Up to 8 discrete
tip and ring
interfaces
Internet
POTS
V.90 modem
at 56 kbps
SU
PSTN
SU
ES4
E1
RBU
NIU
SU

V.35 Application
Internet
Router
Router
V.35
SU
ES4
Router
Or SMS
E1 or 100BaseT
NIU
Rates up to 256 kbps in PW2K
Rates up to 4.096 Mbps in PW4K
RBU
E1
PSTN

Integrated Services Digital Network (ISDN)
ISDN provides circuit-switched
data/voice service
POTS
64 kbps
fax
PSTN
Internet
Data
Terminal
ISDN
PBX
S/T
Interface
2B+D
Rate only
SU
ES4
ISDN
central
office
E1
ISDN
Router/Bridge
Ethernet
LAN
SU
RBU
NIU

S-CDMA Fixed Wireless Access Overview
Overview of S-CDMA
Comparison to Other FWA
Technologies
Applications & Advantages
–Circuit Switched Voice and Data
–Packet Switched Voice & Data
–Internet Access Implementations
–Quality of Service and VoIP

PrimeWave 2000 Data Network Architecture
10BaseT
RJ-45
Ethernet
SU
Ethernet
LAN
Ethernet
SU
IP Router/
Firewall
IP Router/SMS/
VoIP Gateway
Ethernet
Hub/Bridge
Ethernet
SU
10BaseT
RJ-45
Internet
POTS
RJ-11
VoIP
Gateway/
IP Router
10BaseT
RJ-45
10BaseT
RJ-45
Ethernet
SU
PrimeWave
RBU
E1
PrimeWave
NIU
PSTN

PrimeWave 2000 Data Network Architecture
PrimeWave offers packet data services using an Ethernet
10BaseT interface
PrimeWave is a Wireless Ethernet Switch
– Switch: A network device connecting multiple LANs that use identical LAN
protocols. The switch acts as an address filter, switching packets between
between LANs without modifying the contents of the packets.
IP
Switch
Switch
IP
Ethernet/
IEEE
802.3
Ethernet/
IEEE 802.3
Ethernet/
IEEE 802.3
Ethernet/
IEEE
802.3
10BaseT
10BaseT
Prime
Wave
PHY
Prime
Wave
PHY
10/
100BaseT
10/
100BaseT
Internet
Or
Local IP
Network
PC or other
IP-based
LAN device
PrimeWave
SU
PrimeWave
RBU
IP Router/SMS

Bandwidth Allocation and System Loading
Light loading (Load < 25%)
– Connect rate = Provisioned rate
– Connection hold time = Long (60 seconds)
Moderate Loading (25% < Load < 75%)
– Connect rate = Provisioned rate
– Connection hold time = Moderate (5 seconds)
Heavy Loading (Load > 75%)
– Connect rate = min{ Provisioned rate, 128 kbps }
– Connection hold time = Short (2/3 seconds)
Very Heavy Loading (Load > 90%)
– Connect rate = min{ Provisioned rate, 64 kbps }
– Connection hold time = Short (2/3 seconds)

S-CDMA Fixed Wireless Access Overview
Overview of S-CDMA
Comparison to Other FWA
Technologies
Applications & Advantages
–Circuit Switched Voice and Data
–Packet Switched Voice & Data
–Internet Access Implementations
–Quality of Service and VoIP

Internet Access Implementations
IP Router-based:
– IP Router connected to RBU
– Configured for desired QoS and network connectivity
– Router may perform accounting and IP address
management (e.g. NAT or DHCP)
– Wireless authentication via PW2K
– Users always on (e.g. no log-in)
– An external device, such as the Allot
NetEnforcer, could be used for enhanced QoS,
accounting and billing features.
– Perhaps cheaper than VPN approach
– Cisco router vs. Redback SMS

Example: ISP using an IP Router
Ethernet/
802.3
10/100BaseT
Ethernet/
802.3
LAN
SU
Internet
IP Router
SU
Ethernet/
802.3
10/100BaseT
Ethernet/
802.3
10/100BaseT
SU
RBU
IP Router
(Cisco 2600)

Internet Access Implementations
VPN-based:
– Layer 2 VPN (IEEE 802.1Q)
– Layer 3 VPN (PPPoE, PPTP, L2TP or IPSec)
– Requires Management device
Advantages:
– Better control of AAA (Accounting,
Authorization and Authentication)
– More secure
– Industry standard for DSL, cable modems, etc.

Example: Layer 2 VLAN using 802.1Q
VLAN #N
10BaseT
SU
Internet
Or Local IP Network
VLAN #2
10BaseT
SU
10BaseT
VPN Access
Concentrator
VLAN #1
10BaseT
SU
SU
RBU #1
10/100BaseT
10/100BaseT
Or
ATM
Or
FR
Ethernet
Switch
10/100BaseT
VLAN Aware
Ethernet
Switch
Ethernet
LAN
10BaseT
SU
RBU #15
NIU

Virtual Private Networking Using PW2K
Layer 2 VPN:
– Based on IEEE 802.1Q VLAN standard
– Each SU has a VLAN identifier which is inserted
into every packet
– RBU and SU are VLAN aware, switching
packets based solely on VLAN ID
– RBU can switch packets from SU-to-SU
– Ability to define closed user groups based on
VLAN Id (e.g. give multiple SUs the same VLAN
ID)
– Considered for future development

Layer 3 VPN
Use Layer 3 protocols including PPPoE, L2TP,
PPTP and IPSec to create a secure VPN
– Common methodology for DSL and Cable Modems
– Layer 2 transport is Ethernet carried over PW2K wireless
air interface
Requires a subscriber management system (SMS)
or VPN Concentrator along with client software.
– PPPoE Example:
– Redback SMS 500 + WinPoET Client Software by Fine Point
Technologies
– PPTP/L2TP/IPSec Example:
– Cisco 3060 VPN Concentrator + Cisco client Software
Available today

Example: Layer 3 VPN Using PPPoE
10BaseT
10BaseT
SU
Internet
Or Local IP Network
SU
10BaseT
SU
10BaseT
SU
10/100BaseT
Ethernet LAN
Router
RBU #1
10/100BaseT
Redback SMS 500
NIU
RBU #15

S-CDMA Fixed Wireless Access Overview
Overview of S-CDMA
Comparison to Other FWA
Technologies
Applications & Advantages
–Circuit Switched Voice and Data
–Packet Switched Voice & Data
–Internet Access Implementations
–Quality of Service and VoIP

Packet-Switched Voice (VoIP)
Alternative to circuit-switched voice lines carried over IP using SIP
or H.323
Carried over Ethernet Interface in PrimeWave 2000
Customers/operators can trade quality for capacity
– Variable compression from 6 kbps up to 64 kbps voice
– Allow up to 3 times more simultaneous voice calls
– Typical delays up to 150 ms compared to 10 ms for circuit-switching
Local Concentration at the SU
– Access Concentrators convert Analog POTS lines to IP over Ethernet
Allows a single IP-based backbone network for voice and a data
– Potential cost savings
Supported today
Ideal for Apartment Buildings, Businesses

VoIP Using PrimeWave 2000
Components
– POP Gateways
– Located at Network Edge (e.g. RBU)
– Responsible for call control, signalling and
accounting
– Responsible for interaction with PSTN or IP network
– Residential Gateways
– Located at SU
– Allow concentration at the SU
– User Devices:
– Softphone and VoIP Phones
– Companies:
– Mediatrix, Oki, Cisco, etc.

Packet-Switched Telephony Application
Analog
Phone/Fax
802.3
POTS (RJ-11)
Mediatrix
802.3
LAN
SU
PSTN
SU
POTS (RJ-11)
Router/Gateway
w/ QoS
10/100BaseT
Cisco AS-8
IP Phone/Fax
802.3
LAN
RBU
Router/
VoIP Gateway
Router/Gateway
w/ QoS
SU
Internet

Quality of Service
PrimeWave offers QoS appropriate for both circuit
and packet-based applications
Circuit-based QoS Criteria (e.g. telephony)
– Availability
– Bit error rate
– Latency
– Voice quality
Packet-based QoS Criteria
– Throughput or data rate
– Bit or packet error rate
– Packet jitter and latency
– Packet prioritization and bandwidth reservation (for real-
time applications)

Packet-based QoS Today
Packet-based QoS
– Nominal BER

Thank You
Presenter:
Brian Bolon
Director of Marketing
L-3 PrimeWave Communications