20-10-2014, 12:14 PM
Abstracts: In this work, the performance of CDMA (Code Division Multiple Access) schemes applied to optical networks is analyzed in terms of the bit error probability. Several types of spreading sequences are studied and performance expressions are derived and confirmed by computational simulation. The types of spreading sequences analyzed are Gold sequences, maximum-length sequences and optical orthogonal sequences. A new optical CDMA receiver with bipolar spreading and optical processing is presented. Additionally, a study on the optical beat interference in optical CDMA systems is performed. It is observed that this type of interference is negligible in such systems. In an IEEE 802.11 system, RSSI is the relative received signal strength in a wireless environment, in arbitrary units. RSSI is an indication of the power level being received by the antenna. Therefore, the higher the RSSI number, the stronger the signal. RSSI can be used internally in a wireless networking card to determine when the amount of radio energy in the channel is below a certain threshold at which point the network card is clear to send (CTS). Once the card is clear to send, a packet of information can be sent. The end-user will likely observe a RSSI value when measuring the signal strength of a wireless network through the use of a wireless network monitoring tool like Wire shark, Kismet or Insider. As an example, Cisco Systems cards have a RSSI_Max value of 100 and will report 101 different power levels, where the RSSI value is 0 to 100. Another popular Wi-Fi chipset is made by Atheros.