Power controlled channel allocation for multiuser multiband UWB systems

Abstract

Abstract-Emerging ultra-wideband (UWB) technology offers a great potential for the design of high-speed short-range communications. However, in order for a UWB device to coexist with other devices, the transmitted power level of UWB is strictly limited by the FCC spectral mask. Such limitation poses a significant design challenge to any UWB system. An efficient management of the limited power is thus a key feature to fully exploit the advantages of UWB. In this paper, a cross layer multiuser multiband UWB scheme is proposed to obtain the optimal subband and power allocation strategy. Optimization criteria involve minimization of power consumption under the constraints on the packet error rate, the data rate, and the FCC limit. To ensure the system feasibility in variable channel conditions, an algorithm to jointly manage the rate assignment of UWB devices, subband allocation, and power control is proposed. A computationally inexpensive suboptimal approach is also developed to reduce the complexity of the problem, which is found to be NP hard. Simulation results under UWB channel model specified in the IEEE 802.15.3a standard show that the proposed algorithm achieves comparable performances to those of the complex optimal full search approach, and it can save up to 61% of transmit power compared to the current multiband scheme in the standard proposal. Moreover, the proposed algorithm can obtain the feasible solutions adaptively when the initial system is not feasible for the rate requirements of the users.Index Terms-Ultra-wideband (UWB), multiband orthogonal frequency-division multiplexing (OFDM), wireless personal area networks (WPANs), power control, channel allocation.

Ultra Wideband Systems with MIMO

“…Another merit of this approach is that the very high sampling rate in the receiver, as required by the IR-based UWB receiver, is greatly relaxed. Other pros and cons of MB-OFDM systems and the treatment of some specific issues existing in MB-OFDM systems can be found in the literature [21,103,144,183,215,223,224,226,227,272,290]. The transmitter (TX) and receiver (RX) structures for a typical MB-OFDM system are illustrated in Figure 4.9a and 4.9b respectively [21].…”

Cross-Layer Resource Allocation for MB-OFDM UWB Systems

“…In (Siriwongpairat et al, 2007), a novel channel allocation scheme is proposed by efficiently allocating power, data rate and sub-bands among all the users. The sub-band and power assignment problem is formulated as an optimization problem whose goal is to minimize the total power under the condition that all users achieve their requested data rates.…”

Spectrum efficiency optimization in multiuser Ultra Wideband cognitive radio networks

“…To maximize the spectrum efficiency in a multiuser cognitive network, the unused spectrums need to be quickly detected and allocated to the cognitive user that can use the detected spectrum as efficiently as possible [7]- [9]. The authors in [7] formulated an OFDM multiuser power minimization problem into a tractable convex optimization problem and used method of Lagrangian multipliers to obtained the solution.…”