Contents
What are the characteristics of DSSS?
Features. DSSS phase-shifts a sine wave pseudorandomly with a continuous string of chips, each of which has a much shorter duration than an information bit. That is, each information bit is modulated by a sequence of much faster chips. Therefore, the chip rate is much higher than the information bit rate.
What is DSSS and OFDM?
DSSS allows data to be spread over a broad band of frequency spectrum, which is resistant to interference while requiring lower power. OFDM multiplexes data onto 52 orthogonal subcarriers using one of several modulation techniques. These subcarriers are then multiplexed into the OFDM carrier.
Why DSSS is considered as resistant to noise?
The DSSS signal gives LPI (a low probability of intercept) because the total signal power is spread over a wide bandwidth and the signal is noise-like, making it hard to detect. This, together with the wide bandwidth of the transmitted signal, makes jamming more difficult than for conventional signals.
What is jamming margin?
jamming margin: The level of interference (jamming) that a system is able to accept and still maintain a specified level of performance, such as maintain a specified bit-error ratio even though the signal-to-noise ratio is decreasing. [
What’s the difference between OFDM, DSSS and DSK?
Hence OFDM offers many benefits for alleviating problems encountered in single carrier systems. This is done by spreading out frequency selective fading over many symbols in OFDM. ➨CCK and DSSS are used for low data rates upto 11 Mbps while OFDM is used for high data rate applications such as 50 to 100 Mbps.
What’s the difference between DSSS and OFDM in 802.11b?
IEEE 802.11b supports four data rates viz. 1 Mbps, 2 Mbps, 5.5 Mbps and 11 Mbps. DSSS is used to provide support for 1 Mbps and 2 Mbps data rate. CCK for 5.5 and 11 Mbps while OFDM is used for higher data rate applications. OFDM is used in IEEE 802.11a, 11g, 11n, 11ac and 11ad versions.
How does a DSSS differ from a FHSS?
Unlike FHSS, DSSS does not hop. It is set to one channel and spreads data across it, and that process is called data encoding. Each bit of data is encoded and transmitted as multiple bits of data. This process of adding the redundant information is known as processing gain .
What kind of data rate does DSSS support?
There are various versions of WLAN standard developed to address different data rate and coverage requirements. IEEE 802.11b supports four data rates viz. 1 Mbps, 2 Mbps, 5.5 Mbps and 11 Mbps. DSSS is used to provide support for 1 Mbps and 2 Mbps data rate.