This paper proposes the use of inter-cell transmission power control (TPC) with overload indicator (OLI) signaling to user equipment (UE) in addition to intra-cell TPC for the Evolved UTRA uplink. In the proposed inter-cell OLI transmission method, a cell site (Node B) selects UEs offering high-level interferences to the cell site based on the measured path loss difference, and then, the cell site transmits the OLI signal to the selected UEs. The simulation results show that the inter-cell TPC improves both the average user throughput and cell-edge user throughput at 5% in the cumulative distribution function (CDF) curve, assuming the same sector throughput. For instance, when the sector throughput is 1 Mbps using 1.08 MHz bandwidth, the inter-cell TPC with the proposed UE-common OLI scheme increases the average user throughput and the 5%-cell edge user throughput by approximately 41% and 53%, respectively, compared to the case with intra-cell TPC only. Furthermore, when the inter-cell TPC with the proposed UE-individual OLI is employed, the corresponding average user throughput and the 5% user throughput are increased by approximately 87% and 94%, respectively.

This paper presents the optimum control interval for intra-cell fractional transmission power control (TPC) for a shared data channel employing frequency domain channel-dependent scheduling and adaptive modulation and coding (AMC) in the Evolved UTRA uplink using single-carrier (SC)-FDMA radio access. The simulation results show that the best attenuation factor in the fractional TPC is approximately 0.6 for achieving the maximum user throughput when the maximum target received signal power, P0 is -60 dBm. Then, we show that the optimum averaging interval for the desired signal level, which corresponds to a substantial control interval for the fractional TPC, is approximately 100-200 msec regardless of the maximum Doppler frequency up to 222 Hz and the distance at the shadowing correlation of 0.5. Throughout the simulation results, we verify that slow intra-cell fractional TPC associated with fast AMC is effective in achieving the maximum cell throughput and cell-edge user throughput.

In Long-Term Evolution (LTE)-Advanced, heterogeneous networks where femtocells and picocells are overlaid onto macrocells are being extensively discussed in addition to traditional well-planned macrocell deployment to improve further the system throughput. In heterogeneous networks, cell range expansion (CRE), which is a technique for expanding the cell radius of picocells by biasing the handover criteria, e.g., the downlink received signal power, is applied so that the UEs will more frequently select the picocells. This paper investigates a fractional transmission power control (TPC) method suitable for the heterogeneous networks that employ CRE in the LTE-Advanced uplink and evaluates the cell-edge user throughput and cell throughput performance. Simulation results (2-8 picocells and 25 (30) UEs are located within one macrocell with a uniform (cluster) distribution, the difference in transmission power between the macro and picocells is 16 dB, and the Typical Urban and Pedestrian-A channel models are employed) show that almost the same cell-edge user throughput is obtained by setting an appropriate difference in the target received signal power between the macro and picocells according to the CRE offset value.