Abstract
The Ultra Wide-Band Multi Band-Orthogonal Frequency Division Multiplexing (UWBMB-OFDM) systemis a low power (– 41.3 dBm/MHz); short-range (less than 10 m); high speed (53.3 - 480 Mbps) wireless technology with spectral band widthfrom 3.1GHz to 10.6 GHz allocated by Federal Communications Commission (FCC) according to IEEE 802.15.3a standard. The UWB spectrum is divided into 14 subbands, each with 528 MHz bandwidth . Each OFDM symbol is transmitted / received a cross each subband using a single 128-point radix2 IFFT/FFT. In this paper a simulation software is written using Matlab version 10 to evaluate the Bit Error Rate (BER) of the system using the traditional 128-point IFFT/FFT algorithm, and the proposed 4-parallel 32-point radix2 IFFT/FFT algorithm. It has been shown that a time saving is 28.7 % , and that the BER is better off 5dB using the proposed method as compared to traditional method.
Highlights
A substantial change occurred in February 2002 when the U.S Federal Communications Commission (FCC) issued a Report & Order that authorizes the commercial and unlicensed deployment of UWB in the USA [1]
Where N is the number of subcarriers (N =128) and is the modulation input at subcarrier k. This signal is converted from parallel to serial (P/S) and from digital to analog (D/A), added in the first of symbol time of cyclic prefix (TCP) and in the end of it added time of guard interval (TGI)
The simulation results obtained for 128-point IFFT/FFT shown in Fig. (12) in CM1 for different code rates are compared with those obtained from reference [14] shown in Fig. (13) and reference [15] shown in Fig. (14) for a Bit Error Rate (BER) level of as given in table (3)
Summary
A substantial change occurred in February 2002 when the U.S Federal Communications Commission (FCC) issued a Report & Order that authorizes the commercial and unlicensed deployment of UWB in the USA [1]. : IFFT/FFT period : Cyclic prefix duration : Guard interval duration : Symbol duration These subcarriers are configured as shown in Fig. Where N is the number of subcarriers (N =128) and is the modulation input at subcarrier k This signal is converted from parallel to serial (P/S) and from digital to analog (D/A), added in the first of symbol time of cyclic prefix (TCP) and in the end of it added time of guard interval (TGI). The switching is assigned to different users in order to gain frequency diversity while minimizing the multiple access interference These symbols, are transmitted over Sahel-Valenzuela (S-V) channel model [11] which are received by the receiver shown in Fig. For the proposed 4-parallel 32-point described in section III , the OFDM symbols are interleaved in time and frequency for TFC code {1 3 2} as shown in Fig. Channel models (CM) are classified into four types CM1 to CM4 for distances in the range up to 10 m, as given in table (2) [10]
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