Abstract— We study optimal power allocation for a set of parallel channels when the transmitter has limited knowl-edge of the Channel State Information (CSI). This case is typical for mobile OFDMA systems like LTE and LTE¬A where the transmitter relies on CSI feedback from a receiver that is subject to measurement errors, sparse sam¬pling, quantization errors (especially noticeable in MIMO systems), processing and transmission delays. Based upon per-channel targeted Packet Error Rates (PER) we construct a power allocation scheme that maximizes the sum capacity. The optimal algorithm can be cast into a modiﬁed 3-D (Volu¬metric) version of the Water-Filling algorithm. Additionally, the solution obtained here improves performance of real-time delay sensitive trafﬁc such as voice and real-time video by favoring the trafﬁc with lower target PER. Simulations show that the gain in sum capacity over traditional Water-Filling solution can reach as high 90% in some cases.
Index Terms— Wireless Cellular Networks, 3G, 4G, LTE, WCDMA, HSPA, OFDMA, Radio Resource Management, RRM, Waterﬁlling, CSI.
Cite:Leonid Razoumov and Robert R Miller, "Power Allocation Under Transmitter Channel Uncertainty and QoS Constraints: Volumetric Water-Filling Solution," Journal of Communications, vol. 7, no.9, pp.656-659, 2012. Doi: 10.4304/jcm.7.9.656-659
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