Lee Kai Xuan / mbed-os

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Fork of mbed-os by erkin yucel

features/nanostack/FEATURE_NANOSTACK/sal-stack-nanostack/docs/quick_start_hw.md@1:3deb71413561, 2017-07-20 (annotated)

Committer:
xuaner
Date:
Thu Jul 20 14:26:57 2017 +0000
Revision:
1:3deb71413561
Parent:
0:f269e3021894 
mbed_os

Who changed what in which revision?

UserRevisionLine numberNew contents of line
elessair 0:f269e3021894 1 Configuring hardware
elessair 0:f269e3021894 2 ====================
elessair 0:f269e3021894 3
elessair 0:f269e3021894 4 ## Selecting your radio
elessair 0:f269e3021894 5
elessair 0:f269e3021894 6 6LoWPAN network uses IEEE 802.15.4 radios and therefore, operates on one of the following unlicensed
elessair 0:f269e3021894 7 frequency bands:
elessair 0:f269e3021894 8
elessair 0:f269e3021894 9 * 868.0–868.6 MHz: Europe, allows one communication channel (2003, 2006, 2011[4])
elessair 0:f269e3021894 10 * 902–928 MHz: North America, up to ten channels (2003), extended to thirty (2006)
elessair 0:f269e3021894 11 * 2400–2483.5 MHz: worldwide use, up to sixteen channels (2003, 2006)
elessair 0:f269e3021894 12
elessair 0:f269e3021894 13 The data rate varies from 20 kbit/s to 250 kbit/s. The data rate available per node should be considered
elessair 0:f269e3021894 14 when designing the application. Basically, the data rate is divided between all nodes in the network.
elessair 0:f269e3021894 15 Roughly half of the channel capacity should be allocated for signalling purposes, and each hop requires
elessair 0:f269e3021894 16 retransmisson of the packet.
elessair 0:f269e3021894 17
elessair 0:f269e3021894 18 ![Datarate](img/bw.png)
elessair 0:f269e3021894 19
elessair 0:f269e3021894 20 <span style="background-color:#E6E6E6;border:1px solid #000;display:block; height:100%; padding:10px">**Rule of thumb:** The bandwidth per node is divided by the number of nodes in the network and the number of hops.</span>
elessair 0:f269e3021894 21
elessair 0:f269e3021894 22 ### FHSS
elessair 0:f269e3021894 23
elessair 0:f269e3021894 24 Frequency Hopping Spread Spectrum (FHSS) is a method of transmitting radio signals by rapidly switching the carrier among many frequency channels, using a pseudorandom sequence known to both the transmitter and receiver. It makes the network more tolerant for narrow band interference and is sometimes required by the FCC rules.
elessair 0:f269e3021894 25
elessair 0:f269e3021894 26 In Nanostack, the FHSS implementation utilizes the standard 802.15.4 radios and switches RX/TX channels in a calculated sequence.
elessair 0:f269e3021894 27 It does not modify the 802.15.4 radio frames in any way, and thus, does not require any special support from the RF chip.
elessair 0:f269e3021894 28
elessair 0:f269e3021894 29