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An analytical formulation of the mean detection time and the distribution of the detection time of a wireless microphone (primary user) in an IEEE 802.22 wireless regional area network (WRAN) is presented. The IEEE 802.22 WRAN has a number of customer-premises equipments (CPEs) in the coverage area of its base station. Out of this number of CPEs, a number of them are within the coverage area of the...
In this paper, a low complexity a posterior probability (APP) detector based on breadth-first tree search algorithm is purposed for coded interleaved frequency division multiple access (IFDMA) system. The proposed detector combines the principles of the M-algorithm with QR decomposition (QRD-M) to generate soft decision statistics in place of the full APP detector which has a high computational cost...
This paper proposes a frequency domain decision feedback data receiver for the uplink transmission of broadband single carrier cyclic prefix-assisted CDMA systems. The optimum data detection problem based on the maximal-likelihood criteria for this system is addressed as a combinatorial optimization problem. A sequential quadratic programming approach is proposed to solve this problem. The parallel...
Active interference cancellation (AIC) is an effective technique to provide interference avoidance feature for an ultrawideband (UWB) OFDM transmitter. Partial transmit sequence-AIC (PTS-AIC), which was recently proposed as an improvement of AIC, requires high computational complexity by doing the exhaustive search of all possible weighting factors whose number grows exponentially with the number...
IEEE 802.15.4b is an enhanced standard to the IEEE 802.15.4, addressing the needs for high-data rate transmission using 868 or 915MHz band in the wireless personal area networks. This paper details a modulation and code mapping scheme designed specifically for the standard's high rate transmission schemes operating in the 868MHz and 915MHz bands; which leads to efficient transmission and low implementation...
Non-coherent ultra-wideband (UWB) impulse radio systems are easier to implement than their coherent counterparts, because the strict synchronization requirements are relaxed. The trade-off for simplicity is a loss in performance. The pulse-repetition interval (PRI) for non-coherent UWB schemes is limited by the maximum channel delay, to avoid intersymbol interference (ISI). This affects the maximum...
Multi-band ultra-wideband (MB-UWB) divides the available spectrum into multiple subbands, in which certain bands may be turned off to eliminate possible interference and coexistence problems with other wireless services using the same spectrum. Another possibility arising from MB-UWB is the assignment of different time-frequency subband hopping patterns to support simultaneously operating piconets...
The Automatic Repeat Request (ARQ) scheme makes use of error detection to identify if retransmission is required. Hybrid ARQ (HARQ) uses an error control code in conjunction with ARQ and can reduce the number of transmissions required, thus giving a better goodput performance. When packet combining (PC) is carried out in the HARQ scheme, PER can be greatly improved. This paper investigates the performance...
In this paper, detection of digital TV signals is studied since there is strong motivation to better utilize the idle TV channels to improve spectral efficiency, as seen in the efforts of IEEE 802.22 Wireless Regional Area Networks (WRAN) international standard activities. Cyclostationary feature of DVB signals is explored so that the robust single-cycle detector (SCD) can be employed to handle the...
Recent research have shown that spectrum can be utilized more efficiently through secondary usage of frequency bands which has been occupied by an existing system. In the future, the secondary radio operator may also want to provide Grade-of-Service (GoS) guarantee to its users. Our model assumes a primary and a secondary system, with both having GoS requirement, and another secondary system with...
An improved recursive algorithm for BLAST is proposed. The speedups of the improved recursive algorithm over the original recursive algorithm in the number of multiplications and additions are 1.47 and 1.2 respectively.
This paper addresses cyclic delay diversity (CDD) in an ultra-wideband communication system based on orthogonal frequency division multiplexing (OFDM) technique. Symbol error rate and outage probability have been derived. It is shown that with only two transmit antennas, CDD effectively improves SER performance and reduces outage probability significantly especially when the channel delay spread is...
This paper evaluates enhanced space time coded diversity feature proposed in IEEE 802.16e (Amendment of 802.16-2004 standard for combined Fixed and Mobile Broadband Wireless Access operation in licensed band), under 2048 points orthogonal frequency division multiple access (OFDMA) mode of operation. It is shown that the current transmit diversity matrix does not fully exploit selection gain available,...
In this paper, enhanced space time coded diversity feature of IEEE 802.16e (amendment of 802.16-2004 standard for combined fixed and mobile broadband wireless access operation in licensed band), under 2048 points orthogonal frequency division multiple access (OFDMA) mode of operation, are evaluated. It is shown that the current transmit diversity matrix does not fully exploit selection gain available,...
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