Rainbow Electronics AT86RF231 - Manual (Page 137)

137
8111A–AVR–05/08
AT86RF231
11.3 High Data Rate Modes
The main features are:
• High Data Rate Transmission up to 2 Mb/s.
• Support of Basic and Extended Operating Mode
• Support of other features of the Extended Feature Set
11.3.1 Overview
The AT86RF231 also supports alternative data rates, higher than 250 kb/s for applications
beyond IEEE 802.15.4 compliant networks.
The selection of a data rate does not affect the remaining functionality. Thus it is possible to run
all features and operating modes of the radio transceiver in various combinations.
The data rate can be selected by writing to register bits OQPSK_DATA_RATE (register 0x0C,
TRX_CTRL_2).
The High Data Rate Modes occupy the same RF channel bandwidth as the IEEE 802.15.4-
2.4 GHz 250 kb/s standard mode. Due to the decreased spreading factor, the sensitivity of the
receiver is reduced accordingly.
Table 11-8 on page 137 shows typical values of the sensitivity
for different data rates.
By default there is no header based signaling of the data rate within a transmitted frame. Thus
nodes using a data rate other than the default IEEE 802.15.4 data rate of 250 kb/s are to be con-
figured in advance and consistently. Alternatively the configurable start of frame delimiter (SFD)
could be used as an indicator of the PHY data rate, see
Section 11.9 “Configurable Start-Of-
Frame Delimiter” on page 155 .
11.3.2 High Data Rate Packet Structure
In order to allow appropriate frame synchronization, higher data rate modulation is restricted to
the payload octets only. The SHR and the PHR field are transmitted with the IEEE 802.15.4
compliant data rate of 250 kb/s, refer to
Section 8.1.1 “PHY Protocol Layer Data Unit (PPDU)”
on page 79 .
A comparison of the general packet structure for different data rates with an example PSDU
length of 80 octets is shown in
Figure 11-6 on page 138 .
Table 11-8. High Data Rate Sensitivity
High Data Rate Sensitivity Comment
250 kb/s -101 dBm PER
≤ 1%, PSDU length of 20 octets
500 kb/s -97 dBm PER
≤ 1%, PSDU length of 20 octets
1000 kb/s -95 dBm PER
≤ 1%, PSDU length of 20 octets
2000 kb/s -89 dBm PER
≤ 1%, PSDU length of 20 octets