Hardware and Software
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- Date Submitted: 06/25/2014 03:28 PM
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FDMA
FDMA utilizes Frequency Division Modulation (FDM) to separate the given spectrum into individual analog bands or channels. According to (Goleniewski, 2007) each FDMA cell is able to facilitate about 60 users, which is a very low number by standards. FDMA is a critical part of other multiple techniques used to divide spectrums into channels before other modulation techniques are applied.
TDMA
A channel access that is shared and used on medium networks. TDMA is also known as the 2G network, and is being phased out slowly. TDMA allows multiple users to share the same channel within a network. This is done by splitting a single channel into multiple time slots in order to maximize data flow. TDMA is primarily used within the cell phone industry, and has many advantages, including being easily adaptable, provides extended battery life, and being cost effective. The main disadvantage of TDMA is dropped calls.
CDMA
Based on Direct Sequence Spread Spectrum (DSSS), is what makes CDMA unique from FDMA and TDMA, because it will allow users to operate on the same frequency simultaneously. Early CDMA operated at 1.25 MHz, with newer generations, known as Wideband CDMA, operating at 3 MHz, 10 MHz, and 15 MHz (Goleniewski, 2007). The larger channels allow it to carry more calls and implement superior encryption. Compared to FDMA and TDMA, the spectral efficiency of first generation CDMA networks have a better resistance to interference and better security, because DSSS converts each bit into micro pulses called chips. According to Langton (2002), the current standard of CDMA, CDMA 2000, performs modulation three times. The three modulations are known as Short Code, Long Code, and Walsh Code.
OFDM
OFDM divides data pieces into many RF channels, and then sends them over a frequency. In OFDM, each tone is independent to other tones. OFDM eliminates the requirement for guard bands to separate the frequencies and avoid interference from other RF channels. In doing this,...
FDMA utilizes Frequency Division Modulation (FDM) to separate the given spectrum into individual analog bands or channels. According to (Goleniewski, 2007) each FDMA cell is able to facilitate about 60 users, which is a very low number by standards. FDMA is a critical part of other multiple techniques used to divide spectrums into channels before other modulation techniques are applied.
TDMA
A channel access that is shared and used on medium networks. TDMA is also known as the 2G network, and is being phased out slowly. TDMA allows multiple users to share the same channel within a network. This is done by splitting a single channel into multiple time slots in order to maximize data flow. TDMA is primarily used within the cell phone industry, and has many advantages, including being easily adaptable, provides extended battery life, and being cost effective. The main disadvantage of TDMA is dropped calls.
CDMA
Based on Direct Sequence Spread Spectrum (DSSS), is what makes CDMA unique from FDMA and TDMA, because it will allow users to operate on the same frequency simultaneously. Early CDMA operated at 1.25 MHz, with newer generations, known as Wideband CDMA, operating at 3 MHz, 10 MHz, and 15 MHz (Goleniewski, 2007). The larger channels allow it to carry more calls and implement superior encryption. Compared to FDMA and TDMA, the spectral efficiency of first generation CDMA networks have a better resistance to interference and better security, because DSSS converts each bit into micro pulses called chips. According to Langton (2002), the current standard of CDMA, CDMA 2000, performs modulation three times. The three modulations are known as Short Code, Long Code, and Walsh Code.
OFDM
OFDM divides data pieces into many RF channels, and then sends them over a frequency. In OFDM, each tone is independent to other tones. OFDM eliminates the requirement for guard bands to separate the frequencies and avoid interference from other RF channels. In doing this,...