- WPAN = wireless personal area networks
- POS = personal operating space
- user scenarios
- connection of peripheral devices
- support of ad-hoc networking
- bridging of networks
Bluetooth operates on 79 channels in the 2.4 GHz ISM band with 1 MHz carrier spacing.
apply FHSS for interference mitigation
FH-CDMA for separaton of networks
- piconet
A piconet is a collection of Bluetooth devices which are synchronized to the same hopping sequence.
M = master
one device
determines the hopping pattern in the piconet
S = slave
all the other connected to the master
up to seven simultaneous slaves
AMA = active member address (3-bit)
all active devices are assigned a AMA
P = parked can not actively participate in the piconet, but are known and can be reactivated within some milliseconds
more than 200 devices can be parked
PMA = parked member address (8-bit)
all parked devices use a PMA
SB = standby
do not need an address
the hopping pattern is determined by the device ID, a 48-bit worldwide unique identifier
the phase in the clock pattern is determined by the master’s clock
All users within one piconet have the same hopping sequence and share the same 1 MHz channel.
scatternet
many piconets with overlapping coverage can exist simulaneously
As soon as a master leaves a piconet, all traffic within this piconet is suspended until the master returns.
- protocol stacks
core specifications
radio
specification of the air interface
baseband
description of basic connection establishment, packet formats, timing, and basic QoS parameters
linked manager protocol
link set-up and management between devices including security functions and parameter negotiation
logic link control and adapatation protocol (L2CAP)
adaptation of higher layers to the baseband
service discovery protocol
device discovery in close proximity plus querying of service characteristics
profile specification
cable replacement protocol
RFCOMM = radio frequency comm.
TCS BIN = telephony control protocol specification – binary
HCI = host controller interface
between the baseband and L2CAP
provide a command interface to the baseband controller and link manager
BNEP = Bluetooth network encapsulation protocol
OBEX = Object exchange
Calender and business card objects (vCalender/vCard) can be exchanged using the object exchange protocol
AT = attention sequence
SDP = service discovery protocol
- radio layer
bluetooth transceivers use Gaussian FSK for modulation
Power Class 1 (100mW)
Power Class 2 (2.5mW)
Power Class 3 (1mW)
- baseband layer
TDD
1-slot/3-slot/5-slot packets
baseband packet format (bits)
access code 68(72)
preamble 4
sync. 64
(trailer 4)
packet header 54
AM address 3
type 4
flow 1
ARQN 1
SEQN 1
HEC 8
payload (0-2744) Up to 343 bytes
- physics links
two types
SCO = synchronous connection-oriented link
ACL = asynchronous connectionless link
FEC = forward error correction
CVSD = continuous variable slope delta
payload header
link manager protocal
authentication, pairing and encryption
synchronization
capability negatiation
quality of service negotiation
power control
link supervision
state and transmission mode change
low power state
sniff state
keeps its AMA
hold state
park state
release AMA and recieve PMA
all PDUs sent to parked slaves are broadcast
- L2CAP
L2CAP provides three different types of logical channels that are transported via the ACL between master and slave
connectless
connection-oriented
signaling
CID = channel identifier
PSM = protocol/service multiplexor
1 : SDP
3 : RFCOMM
5 : TCS – BIN
> 4096 : assigned dynamically
IEEE 802.15
Erica--PrettyITGeek 