Cypress CY62167EV18 Bedienungsanleitung PDF herunterladen (Seite 19)

US

2012/0147184

A1

energy

consumption

in

the

Wireless

camera.

These

techniques

are

listed

and

explained

in

further

detail

below:

[0107]

1.

Move

the

camera

Web

server

to

the

base

station

and

re-deploy

it

as

a

virtual

Web

server.

[0108]

2.

Cycle

the

image/

sensor

bulk,

high-bandWidth

data

transmission

radio

based

on

the

needs

of

the data

rate

and

channel

capacity.

[0109]

3.

Cycle

the

image

capture

module

(hardWare

or

software)

based

on

the

most

ef?cient

use

of

the

module

vs.

latency,

start-up/

shut

doWn

time

and

storage

capacity

needs.

[0110]

4.

Cycle

the

compression

module

(hardWare

or

soft

Ware)

based

on

the

most

ef?cient

use

of

the

module

vs.

latency,

start-up/

shut

doWn

time

and

storage

capacity

needs.

[0111]

5.

Use

of

a

secondary

loW-bandWidth

radio

With

a

longer

range

than

the

bulk

radio

for

camera

control

and

status

report

and

triggering

signals.

[0112]

6.

Activation

of

the

camera

functions

based

on

vari

ous

triggering

events.

[0113]

7.

Use

of

environmental

energy

sources.

[0114]

8.

Use

of

pulsed

high

e?iciency

light

emitting

diode

(LED)

devices

to

illuminate the

?eld

of

vieW.

[0115]

Energy

Saving

Technique

1:

Move

the

camera

Web

server

to

the

base

station

and

re-deploy

it

as

a

virtual

Web

server.

[0116]

One

notable

feature

of

the

Wireless

camera

described

in

this

speci?cation

is

that

the

Wireless

camera

does

not

directly

service

requests

for

data

received

via a

Web

server

or

a

relay

server

mechanism.

This

is

because

there

is

no

need

for

a

Web

server

to

be

running

in

the

Wireless

camera.

Instead,

data

transmission

can

be

initiated

and

controlled

by

the

burst

transmission

store/control

block

of

the

Wireless

camera.

A

substantial

poWer

saving

can

be

achieved

through

this

tech

nique

because

it

eliminates

the

need

for

Web

server

function

ality

to

be

present

in

the

camera

and

alloWs

the

link

radio

to

poWer

doWn

until

sensor

and image

data

has

to

be

transferred,

not

When

the

client

application

needs

data.

(See

poWer

saving

technique

2

beloW

for

further

discussion.).

HoWever,

through

the

use

of

the

Web

server

mechanism

the

camera

data

can

be

available

to

client

applications

using

standard

netWork

means

such

as

IP,

HTTP,

HTTPS,

TCP,

ICMP,

UDP,

SMTP,

FTP,

DHCP,

UPnPTM,

Bonjour,

ARP,

DNS,

DynDNS,

802.1X,

and

NTP.

[0117]

Energy

Saving

Technique

2:

Cycle

the

image/

sensor

data

transmission

radio

based

on

the

needs

of

the data

rate

and

channel

capacity.

[0118]

Technique

2

cycles

a

high-bandWidth

radio

bursting

data

on

a

periodic

basis

determined

by

a

burst

period.

BetWeen

the

burst

transmissions

the

high-bandWidth

radio

can be

poWered

doWn.

On

average,

the

energy

needed

to

transfer

data

can be

optimiZed

In

one

implementation,

an

802.11

based

physical

layer

technology

can

be

used

to

trans

fer

the

bulk

data.

The

physical

layer

technology

used

can

include

broadband

high

ef?ciency

OFDM

modulation

archi

tectures.

The

OFDM

modulation

technique

can

exhibit

loW

energy

per

bit

transferred

per

unit

of

range

vs.

other

com

monly

used

radio

link

architectures,

such

as

the

802154

OOC/FSK

modulation

techniques.

[0119]

The

Wireless

camera

can

include

a

high-bandWidth

radio

transceiver,

Which

can

operate

under

a

steady

state

communication

condition.

For

example,

the

Wireless

camera

media

access

control

(MAC)

for

the

high-bandwidth

radio

can

be

programmed

to

setup/tear

doWn

connections

as

deter

mined

by

the

Transmission

Store/Control

Block.

This

alloWs

Jun.

14,

2012

the

high-bandwidth

bulk

data

transmission

radio

to

poWer

doWn

completely

for

extended

periods

of

time.

[0120]

When

the

radio

is

sWitched

on

it

can

be

instantly

assumed

to

be

logically

linked

With

the

base

station.

A

primi

tive

MAC

layer

can

be

used,

but

this

may

not

be

the

preferred

implementation.

Thus,

the

radio

can

avoid

the

usual

discovery

period,

and

advance

to

the

authentication

request

and

reply,

folloWed

by

the

associated

request

and

reply

messages

in

a

three-Way

handshaking

process.

This

differs

from

the

regular

beacon

behavior

of

802.11

When

operating

in

a

rendeZvous

mode.

Discovery

sequences

can

be

suppressed

except during

initialiZation/

installation

conditions.

A

very

light

OS

can run

on

the

Wireless

camera

to

bring

up

the

MAC

With

the

minimal

con?guration.

This

can

reduce

the

need

for

the

poWer

and

time

consuming

mechanisms

associated

With

current

Wireless

link

technologies.

In

certain

implementations,

the

MAC

layer

can

almost

be

entirely

eliminated

from

the

camera and

a

rudimentary

slave

response

can

be

implemented

Which

responds

to

control

signals

received

from

a

secondary,

loW

poWer,

loW-bandWidth

radio

channel.

[0121]

The

algorithm

for

the

burst

transmission

processing

is

a

timing

loop

Where

data

is

transmitted

based

on

the

data

rate

used

and

the

available

channel

characteristics.

A

calcu

lation

is

done

to

determine

the

optimum

timing

for

the

burst

transmission

and

the

system

is

then

set

up

to

match

this

as

closely

as

possible.

During

non-transmission

periods

the

high-bandwidth

radio

can

be

completely

poWered

doWn.

This

can be

different

from

“doZe”

or

“standby”

modes

often

pro

vided

by

commercial

integrated

circuits.

These

modes

often

dissipate

energy

at

levels

that

can

defeat

the

possibility

of

extremely

long

term

battery

life.

During

this

non

transmission

time

the

high-bandWidth

radio

can

use

less

than

tens

of

micro

Watts

of

poWer.

[0122]

The

timing

to

transmit

for

the

burst

transmission

is

based

on

the

folloWing

parameters:

Average

Maximum

Chan

nel

BandWidth

is

represented

by

Bm

in

M

bits

per

second

(Mbps).

Channel

bandWidth

is

the

average

bandWidth

that

can be

achieved

by

the

high-bandWidth

link.

Average

sus

tained

Data

Rate

is

represented

by Bs

in

Mbps,

Which

is

the

data

rate

of

captured

audio/video

data.

The

higher

the

rate,

the

better

the ?delity

and

frame

rate

of

the

transmitted

informa

tion.

[0123]

FIG.

4

is

a

diagram

shoWing

the

burst

data

transmis

sion,

according

to

some

implementations.

To

take

advantage

of

the

fact

that

the

sustained

data

rate

Bs

is

much

smaller

than

the

capability

of

the

bulk

radio;

the

transmission

Will

be

on

for

a

brief

period

of

time

to

burst

the

data.

This

period

can

be

designated

by

Tx

(sec),

and

the

time

period

betWeen

bursts

can

be

represented

by

Tc

(sec).

[0124]

Hence

[0125]

Tx.Bm

[0126]

TcIBs

[0127]

Referring

to

the

bottom

of

FIG.

4,

there

canbe

a

time

associated

With

setting

up

the

link

and

terminating

the

link.

For

example,

the

time

to

set

up

link

is

represented

by

Tsu

(see),

and

the

time

to

tear

doWn

link

is

represented

by

Ttd

(sec).

Therefore

the

aggregate

time

to

set-up

and

tear

doWn

link

TW:Tsu+Ttd

(sec).

To

obtain

maximum

poWer

saving

ef?ciency

on

the

bulk,

high-bandWidth

radio,

ideally

the

ratio

of

the

transmit

time

Tx

to

poWer

doWn

time

should

be

equal

to

the

ratio

betWeen

Bs

and

Bm.

[0128]

During

the

Tx

period,

the

poWer

draWn

by

the

high

bandWidth

radio

can

be

very high

relative

to

the

poWer

doWn

periods.

For

example,

the

Wireless

camera

in

the

802.1

in

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