Comparison between pico and wifi ap

@pfesto /yuvi-syamsiana

HetNet with WLAN AP or Pico

Cell


Outline

1. HetNet Introduction

2. Comparing WLAN AP & Pico Cell

a. System Setup

b. Performance Comparison

c. Product Price

3. EAP Authentication

4. Home Agent

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What is HetNet

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Macro BTS

Pico Cell

+WLAN Access Point

Small BTS

• Pico cell is a small BTS which is usually planted in building to extend coverage. The form is small and easily disguised as building accessory.

• WLAN Access Point is the device which broadcast WiFisignal

• HetNet, short from Heterogeneous Network is a network which is a combination of macro BTS (the big tower transmitting 3G/LTE signal) and small BTS


Comparing WLAN AP & PICO CELLSource : http://www.qualcomm.com/media/documents/files/qualcomm-research-a-comparison-of-lte-advanced-hetnets-and-wifi.pdf


System Simulation SetupEach setup will consist of 1 or 4 small cells within 1 macro cell

LTE Advanced Setup• # of macro cells : 57

– D3 (ISD : 1732 m, 700 MHz)– D1 (ISD : 500 m, 2.1 GHz)

• Antenna configuration : 2Tx/2Rx• Antenna Gain:

– Macro : 14 dBi– Pico : 5 dBi

• Penetration Loss : fix 20 DB• Bandwidth : 10 Mhz• Traffic Model : Downlink full buffer• # of UE : 30 per macro (total : 1710)• TX Power

– Macro : 46 dBm– Pico : 30 dBm– UE : 23 dBm

• Scheduler : Proportional fair• Pico Density per macro : Fixed : 0/1/4

WiFi Setup• Carrier frequency : 5.5 GHz

• Antenna Configuration

– AP : 2 Tx/ 2Rx

– Client : 1 Tx / 1 Rx

• Antenna Gain : 3 dBi

• Penetration loss : Fix 20 dB

• Bandwidth : 20 MHz

• Traffic Model : Downlink full buffer +12.5%

• TX Power:

– AP : 24 dBm

– Client : 18 dBm

• Scheduler : Round Robin

• Maximum TxOP : 3 ms

• Packet Size : 1500 bytes

• RTS/CTS : None

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Performance Metrics & Distribution

Measurement Metrics

• Cell Edge Throughput– Defined as the lowest 5th

percentile throughput

– Displayed in multiplication factor (x times increased)

• Median Throughput– Defined as the median

value of the test sample

– Displayed in multiplication factor (x times increased)

Load Distribution Setup

• Uniform Distribution– User end devices are

evenly distributed in the small BTS coverage area

• Hotspot Distribution– Using 30 devices, 20 are in

coverage area of small BTS, and the other 10 are not in coverage

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Performance Comparison - Low

Density AreaHotspot Distribution Uniform Distribution

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4.1

2.8

10.2

4

1.8 1.7

3.3

2.1

0

2

4

6

8

10

12

Median Cell Edge Median Cell Edge

1 Small Cell 4 Small Cells

X times increase

Pico Wifi AP

1.4 1.2

2.82

1 1.1 1.1 1.2

0

2

4

6

8

10

12



X times increased

Pico Wifi AP

Pico cells outperform Wifi AP by min of 1.1x to 6.9x higher throughput



Performance Comparison – High

Density AreaHotspot Distribution Uniform Distribution

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2.11.9

4.2

3

1.81.6

3.5

2.5

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5



X times increased

Pico Wifi AP

1.4 1.4

2.5

2

1.1 1.2

1.7 1.6

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5



X times increased

Pico Wifi AP




Performance Comparison

Summary

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0.00%

20.00%

40.00%

60.00%

80.00%

100.00%

120.00%

0

1

2

3

4

5

6

7

8

9

0.5 1 2 1.5 2.5 7 3 3.5 4 4.5 5 5.5 6 6.5 More

Frequency

Bin

Frequency Cumulative %

This histogram shows the frequency of how many times Pico cell outperform WifiAP by how many multiplication


Mobility Comparison

Picocell

+ Well defined handover procedures as part of 3GPP standard

Wifi AP+ Using Home Agent and Dual

Stack Mobile IP will allow handover from 3GPP network to another non secure RAT

- May interfere with other Wifinetworks

- WAN does not aware of Wifinetworks, thus require UE to perform network discovery

- Wifi does not guarantee connectivity to the strongest AP, it will only switch to other AP when the connection becomes too weak

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Quality of Service Comparison

Picocell

+ Integrated QoS functionality to the macro cell

+ Can use range expansion and resource partitioning to enable equitability in distributing air link resources

Wifi AP

- Four QoS classes (Best Effort, Video, Voice and Background) which is not integrated with 3GPP

- Wifi operates in unlicensed spectrum and rather difficult to ensure no interfering other Wifinetworks which can harm QoS

11-Feb-13 11


Security Comparison

Picocell

+ Using same standard as macro cell (no issue)

Wifi AP

- Require username and password which can negatively impact User Experience (this may be resolved using EAP-AKA/SIM which requires Wifi UE to support EAP-SIM/AKA authentication)

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SON (Self Organizing Network)

Picocell

+ All SON features is fully supported, i.e.

– Mobility Load Balancing

– Automatic Neighbor Relation

– Mobility Robustness Optimization

Wifi AP

- Does not available for inter RAT

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Product Pricing

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Pico Cell

Carrier Grade WLAN

Access Point

• Price Range : USD 7,500.00 – USD 15,000.00

• End User 3G Chipset : USD 30.00

• Approximate Price : USD 2,000.00

• End User Wifi Chipset : USD 5.00

3 – 7 times

6 times


EAP-AKA/SIM

Authentication used in i-WLAN

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EAP-AKA/SIM IntroductionExtensible Authentication Protocol – Authentication and Key Agreement

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2G

3G

EAP-SIM

EAP-AKABased on challenge mechanism and symmetric cryptography

The USIM:• Verifies that AUTN is correct and hereby authenticates the network• If AUTN is correct, the USIM computes RES, IK, CK and provides those

values to the terminal• If AUTN is incorrect, the terminal rejects the authentication.• If the sequence number is out of synchronization, terminal initiates a

synchronization procedure

The terminal• Derives new required keying material from CK and IK• Decrypts the new temporary identifier and saves it to be used on next

authentication• Sends EAP Response/AKA-challenge containing RES to WLAN


EAP-SIM Full AuthenticationBased on RFC-4186

PEER(mobile client)

AUTHENTICATOR(WLAN-AP)

EAP SERVER(RADIUS Server)

EAP-Request/Identity

EAP-Response/Identity

EAP-Request/SIM/Start (AT_VERSION_LIST)

EAP-Response/SIM/Start (AT_NONCE_MT, AT_SELECTED_VERSION)

AuC

Obtain GSM TripletsEAP-Request/SIM/Challenge (AT_RAND, AT_MAC)

Runs GSM algorithms, verifies AT_MAC and derives session keys

EAP-Response/SIM/Challenge (AT_MAC)

EAP-Success

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Attributes Explanation

Generated by Peer1. AT_IDENTITY (IMSI for GSM

Subscribers and NAI for AAA Protocols)

– NAI Format:

• Permanent Username

• Pseudonym Username

• Fast-ReAuth ID

2. AT_NONCE_MT, 2 reserved bytes (all 0) followed by a random number freshly generated by the peer

3. AT_MAC, calculated from HMAC-SHA1-128(K_aut,EAP packet| n*SRES)

Generated by Server1. AT_VERSION_LIST, contains

version numbers supported by the EAP-SIM server (currently there is only version 1 for EAP-SIM)

2. AT_RAND, contains 2 reserved bytes (all 0) followed by n GSM RANDs (generated by HSS/AuC)

3. AT_MAC, short from Message Authentication Code, calculated from HMAC-SHA1-128(K_aut, EAP packet| NONCE_MT)

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Note: MasterKey = SHA1(Identity|n*Kc| NONCE_MT| Version List| Selected Version)


Home Agent and Dual Mobile IP

Stack

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Home Agent Definition

Based on TS 24-304, Home Agent is a mobile IPv4 router on a UE’s home network which tunnels datagrams for delivery to the UE while it is registered on a visited network as

described in IETF RFC 5944.


DMIPSv6 Definition

• Definition : Mobility protocol specified in IETF that provides IP address preservation for IPv4 and IPv6 sessions, allowing the user to roam independently in IPv4 and IPv6

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Handover from GE/UTRAN to I-

WLAN1. UE perform I-WLAN automatic network selection procedure

2. UE perform automatic PLMN selection after receiving PLMN list from WLAN

3. UE initiate tunnel establishment towards PDG

4. Perform Home Link detection

– If UE is still on home link : send Binding Update with lifetime set to 0 to remove binding in Home Agent

– If UE is on not on home link :

• Perform Home Agent Discovery

• H1 PDN attach to Home Agent

• Send Binding Update to Home Agent of its Care-of-Address (UE is still in GERAN or UTRAN during handover)

5. Start detach procedure of GE/UTRAN

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Handover from I-WLAN to

GE/UTRAN1. Start attach procedure

– SGSN will use APN sent by UE to determine the GGSN allocated to the UE

2. Start PDP context activation or GPRS attach

– UE will receive PDP address (Care-of-Address)

3. Start Home Link detection

– If UE is not on home link :

• Initiate Home Agent discovery

• H1 PDN attach (after GPRS attach) or perform Binding Update if already attached

– If UE is on home link :

• Send Binding Update message to Home Agent with lifetime set to 0 to remove binding

4. Start disconnect tunnel procedure

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H1 PDN Attach

1. Discovery of the Home Agent address in IPv6 and IPv4, this is why the DSMIP is required

2. Security association establishment, using IPsec if UE is not in the home link. IKEv2 is used to establish the IPsec

3. IPv6 home network prefix assignment and home link detection

4. IPv4 home address assignment

5. Initial binding registration

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Glossary

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Glossary

1. Home Link : In 3GPP environment, an UE is considered to be in the home link if the UE is connected to one of 3GPP Access Network, for example, GERAN, UTRAN or E-UTRAN. EPS should allow operator to configure which access network is considered as home link for certain UE

2. H1 : Reference point for signaling and user data transfer between UE and Home Agent3. ISD (Inter Site Distance) : distance from one macro site (BTS) to another. Usually, ISD is

less than the diameter of a site to provide an overlapping area to handover4. SON (Self Organizing Network) : it is a feature in LTE by which LTE network can adjust

its parameters based on certain observation made by itself5. ANR (Automatic Neighbor Relation) : feature of SON by which it can automatically find

adjacent neighbors6. MLB (Mobility Load Balancing) : feature to automatically reselect or handover UE in the

edge cells to cope with unequal traffic load7. MRO (Mobility Robustness Optimizations) : feature to automatically adjust thresholds

related to cell reselection and handover in order to eliminate unnecessary handover and to provide appropriate handover timing

8. 2Tx/2Rx : A condition where there are 2 transmitters in the BTS and 2 receivers in UE to accelerate performance

9. Penetration Loss : Reduce of power when the signal transmitted is blocked by concrete wall


Glossary - 2

1. TxOP (Transmit Opportunity) : a bounded time interval during which a station can send as many frames as possible

2. RTS/CTS (Request to Send/Clear to Send) : An additional method to avoid collision caused by hidden node problem in CSMA/CA

3. UE : User Equipment, any user device used to communicate in the network4. I-WLAN : short from Interworking WLAN, when user roams from 3G access to non 3G

access such as WLAN/WiFi5. PLMN : short from Public Land Mobile Network, any network which exist and known

publicly6. PDG : PDN Gateway, the gateway (router) used to communicate with outside network7. GE/UTRAN : technical naming for GPRS/3G8. Care-of-Address (CoA) : temporary IP address for a mobile device. This allows a home

agent to forward messages to the mobile device. A separate address is required because the IP address of the device that is used as host identification is topologically incorrect. The CoA splits the dual nature of an IP address, that is, its use is to identify the host and the location within the global IP network

9. PDP context : session when a UE attach to GPRS network


References

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References

• http://paginas.fe.up.pt/~mricardo/08_09/cmov-mieic/slides/dsmip+802-21.pdf

• http://www.qualcomm.com/media/documents/files/qualcomm-research-a-comparison-of-lte-advanced-hetnets-and-wifi.pdf

• http://news.ycombinator.com/item?id=4229305• http://wireless.agilent.com/rfcomms/refdocs/1xevdo/1xevdola_dc_eap_

aka.html• http://www.3gpp.org/ftp/tsg_sa/WG3_Security/TSGS3_26_Oxford/Doc

s/PDF/S3-020650.pdf• http://www.greenpacket.com/technology_Solutions_Authentication.html• http://agsm.sourceforge.net/talk/EAP-SIM.ppt• http://wifidataoffload.files.wordpress.com/2010/12/3gwifi-seamless-

offload.pdf• http://www.nec.com/en/global/solutions/nsp/lte/pdf/son.pdf• http://www.3gpp.org/• http://www.etsi.org/

Technology

Comparison between pico and wifi ap