Bluetooth and WAP Push Based Location-Aware Mobile Advertising Syst

em

Lauri Aalto Nicklas Göthlin Jani Korhonen Timo Ojala

MobiSys’04, June 6-9, 2004, Boston, Massachusetts, USA.

Outline

Introduction B-MAD (mobile advertisement )system Filed trail and evaluation Discussion and conclusion

Introduction

Mobile advertisement - bus , train - mobile phone , PDA Specific customer for nearby stores focus on permission-based advertising, ruling out unsoli

cited advertising Based on bluetooth positioning A new location-aware mobile advertising system

B-MAD System

B-MAD System

Bluetooth Sensor discovers the globally unique Bluetooth device addresses (BD_ADDRs) of nearby end user devices.

Bluetooth Sensor sends the addresses over a WAP connection to the Ad Server, together with a location identifier.

Ad Server maps the addresses to the user phone numbers (MSISDNs) and checks from the database .

The undelivered advertisements are sent to Push Sender for delivery.

Push Sender delivers the advertisements to end user.

Bluetooth feature

Low power and short distance transmission Operates in the 2.4 GHz unlicensed ISM (industrial, science,

medical ) band Max data rate 723.2k bps Max transmission distance 10m~30m (1mW~3mW)

Piconet - Collection of devices connected in an ad – hoc network One unit acts as master and the others as sl

aves for the piconet - Master : device that initiates a data exchange - Slave : device that responds to the master Slaves have to synchronize Each piconet has one master and up to 7 si

multaneous slaves

M

M

SS

S

S

P

sb

sb

P

P

M=Master SB=Standby

P=Parked S=Slave

Bluetooth Network Topology

Master connected many slaves - polling

A lot of Slaves transmit to master - round robin

Bluetooth Network Topology

Active mode: Bluetooth device receiving for master transmission. Shortest response time but large power consumption Periodic master transmissions used for sync.

Sniff mode: device periodically exchange Active mode to receive

from master transmission and sleep Save power

Bluetooth connection state

Hold mode Master and slave agree on a time duration for which the

slave is not connection Park mode

Slave gives up AM_ADDR Listens periodically for a beacon packet transmission to

synchronize and uses PM_ADDR/AR_ADDR for unparking

Save max power

Bluetooth connection state

Bluetooth Addressing BD_ADDR: Bluetooth Device Address AM_ADDR: Active Member Address PM_ADDR: Parked Member Address AR_ADDR: Access Request Address

Bluetooth Addressing

Packet Format

Access Code: timing synchronization, offset compensation, paging and inquiry. Three types : Channel Access Code (CAC), Device

Access Code (DAC) and Inquiry Access Code (IAC). Header: information for packet acknowledgement, packet

numbering for out-of-order packet reordering, flow control, slave address and error check for header.

Bluetooth packet

Bluetooth feature

FHSS (Frequency hopping spread spectrum communication 跳頻式展頻通訊技術 )

- Frequency hopping cycle =625 us (1600 times per seconds) - 每隔一段時間切換傳送頻率 - 避免訊號干擾　 - 保密性 　

Frequency Hopping & Time Division

fk+2

625 sSlot 3

fk+3

Frame 2

Slot4

t

fk+1

Frame 1

Slot2

Master

Slave1

fk

625 sSlot 1

Fk (frequency channel=79)

Multi-Slot Framing

Frame

fk+3

Slot4

t

• To increase bandwidth Bluetooth can aggregate multiple slots in one direction

of the transmission

• Bluetooth supports 1/1, 3/1, and 5/1 framing (example above is 3/1)• 5/1 framing supports up to 721Kbps, Bluetooth’s maximum capacity

Master

Slave1

fk

625 ms

Slot 1 Slot2

fk

Slot 3

fk

Bluetooth Sensor operation

Bluetooth Sensor - inquiry state it continuously transmits inquiry packets carrying an access code and hops frequencies 3200 times a second - Bluetooth Sensor periodically scans for nearby Bluetooth devices - Run the Bluetooth Sensor software on the mobile phone eg. Nokia 3650 or PDA. - implemented the Bluetooth Sensor in the Symbian OS and Nokia Series 60 version environment

Bluetooth Sensor operation

When it(end user) receives an inquiry packet, it first waits for a random period of time. Then it listens for another inquiry packet and responds to it

This packet carries all necessary information for establishing a connection between the devices

random delay is to avoid all nearby devices responding simultaneously to the first inquiry packet

In order to discover all discoverable devices in an error-free environment, the device must spend at least 10.24 seconds in the inquiry mode

Series 60 Developer platform

Nokia Series 60 Developer platform feature - is a purpose-built operating system for smart phones - Minimum 176 x 208-pixel color screen - keypad layout - Digital camera - Advanced telephony features - Messaging - Internet browsing

Series 60 Developer platform

Series 60 Developer platform technologies

- communications Telephony Infrared (IR) Bluetooth wireless technology - Messaging Short Messaging Service (SMS). Multimedia Messaging Service (MMS). E-mail - Internet browsing WAP

WAP Operation

The Bluetooth Sensor sends the unique Bluetooth device addresses (BD_ADDR) of discovered phones to the Ad Server over a WAP connection

OPEN WAP (wireless application protocol)

Apply to mobile phone or wireless device Internet’s data deliver to end user WML (wireless markup language) - Limited . Small screen . I/O capability . Memory . CPU calculation capability . Network Bandwidth . Latency - efficiently

WAP (wireless application protocol)

Difference of HTML and WML

WAP (wireless application protocol)

Translator

WAP (wireless application protocol)

Advertisement Server Operation

Architecture of Ad Server - Linux + Apache + PHP + Mysql When an end user subscribes to the mobile advertisement service,

end user phone number (MSISDN) and Bluetooth device address (BD_ADDR) is stored in a database

When the Ad Server receives a request from a Bluetooth Sensor, Ad server scans the database for known BD_ADDRs in the request that can be mapped to user accounts

if there are then sends advertisements to Push Sender

Push Sender Operation

Sending WAP message Transmit messages to a proxy

gateway use a short message service to

deliver it

Qualitative Evaluation With A Field Trial

Experiment environment 35 test user Data was collected via a

questionnaire Usually the receiving

distance was some 15–20 m

Qualitative Evaluation With A Field Trial

Discussion And Conclusion

Privacy and security - Device address data sent from a Bluetooth Sensor to the Ad Server is not encrypted - The Ad Server and the Push Sender send Push messages as plain HTTP requests - information Must not be disclosed to third parties

WAP (wireless application protocol)

Bearers ( 底層數據服務 )Support service. Error detection. Segmentation and assemble. Addressing. Routing

OPEN WAP (wireless application protocol)

Transport Layer (wireless datagram protocol) - define different port form different function or program - like IP layer Security Layer (wireless transport layer security) - encryption - compress Transaction Layer - class 0 : like UDP - class 1 : like 2-way handshake - class 2 : like 3-way handshake

OPEN WAP (wireless application protocol)

Session Layer (wireless session protocol) - support two service for transaction layer - connection oriented - connection-less oriented