Residue number system assisted fast frequency-hopped synchronous ultra-wideband spread-spectrum multiple-access: a design alternative to impulse radio

Abstract

Abstract-Ultra-wideband (UWB) systems having a bandwidth on the order of gigahertz have recently received wide attention both in the U.S. and in Europe. The family of UWB systems may communicate either by generating ultra-wideband signals or with the aid of innovatively combining conventional narrowband, wideband, or broadband signals. At the time of writing, UWB systems have only been implemented using ultra-wideband signals, such as those known from impulse radio systems. Hence, in this paper, UWB systems using narrowband signals are explored as a design alternative, which are based on the well-known family of frequency-hopping (FH) spread-spectrum multiple-access techniques. In the proposed UWB system, FH is implemented using multistage frequency-hpping multiple access (MS/UWB FHMA). We highlight the principles of the synchronous MS/UWB FHMA communication system, investigate the associated spectrum assignment, and the residue number system (RNS) based FH strategy. Detection of the received signal can be achieved with the aid of existing fast FH signal detection schemes. Our study shows that the RNS assisted FH strategy is capable of efficiently dividing the huge number of users supported by the synchronous MS/UWB FHMA system into a number of reduced-size user groups, where the multiuser interference only affects the users within the same group. Since the number of users in each group is only a small fraction of the total number of users supported by the synchronous MS/UWB FHMA system, advanced multiuser detection algorithms can be employed for achieving near-single-user performance at an acceptable complexity. Our results show that MS/UWB FHMA is capable of supporting an extremely high number of users, while employing relatively simple receivers.Index Terms-Frequency-hopping (FH), multiuser detection (MUD), residue number system (RNS), spread-spectrum multiple access (SSMA), ultra-wide bandwidth radio.

Spectral efficient IR-UWB communication design for low complexity transceivers

“…The algorithm is initialized with X and Y, denoting the TDC resolution and diode recovery time [18,39]. The method generateRFPulse in line 6 of the algorithm is used to generate the train of RF pulses as shown in (9). In the in-house prototype UWB platform, this is accomplished by generating a trigger control signal from FPGA to the step recovery diode in transmitter [18].…”

“…n ← n + 1 9: end while 10: end procedure The signaling employed above has a fixed gap, T ms in every symbol, as given in (9). This ensures that minimum separation between pulses is greater than or equal to the recovery time of the diode.…”

Limitantes para a decodificação iterativa de sistemas MFSK multi-usuário

“…Sistemas FH-CDMA(do inglês: Frequency Hopped Code Division Multiple Access) foram introduzidos em [1] e foram propostos para sistemas de banda ultra larga (UWB -do inglês: ultrawideband) em [2]. Este sistema pode ser visto como a concatenação de um canal de acesso múltiplo com N freqüências e T usuários [3] com um código de espalhamento (com saltos em freqüências) para permitir o acesso múltiplo.…”