Julien Guillet

Downlink femto-macro ICIC with blind long-term power setting

Inter-cell interference is a major issue in current wireless cellular systems, in particular with the development of femto-cells. Indeed, macro-femto inter-cell interference coordination is not an easy task and should be performed with a minimum communication between macro- and femto-base stations. We propose a blind inter-cell interference coordination approach, in which each femto base station configures its transmission power autonomously. This power setting aims at maintaining a constant macro-cell performance impact of the femto base station, whatever its location in the macro-cell, i.e., it equalises the macro-degradation. In a 3GPP-LTE context, this approach exhibits a good femto-macro performance trade-off compared to fixed femto base station transmission power.

Downlink femto-macro ICIC with location-based long-term power setting

Inter-cell interference is a major issue in current wireless cellular systems, in particular with the development of femto-cells. Efficient macro-femto inter-cell interference coordination (ICIC) is crucial and should be performed with minimum communication between macro and femto base stations. We propose an ICIC approach, in which each femto base station informs a server about its position, obtains relevant information from mobile terminal measurements stored in a database maintained by the server and configures its transmission power according to this information. This power setting aims at maintaining a controlled impact of the femto base station on macro-cell performance, independent of the femto-cell location. In a 3GPP-LTE context, this approach exhibits a good femto-macro performance trade-off and is robust against power and positioning measurement errors.

Uplink femto-macro ICIC with semi-centralized power control

Inter-cell interference is a major issue in current wireless cellular systems, in particular with the development of femto-cells. We propose a semi-centralized uplink femto-macro ICIC approach with low network signalling in which a coordinator defines a power control function for all femto base stations in a given area based on long-term statistics they build. The power control function takes path gains as arguments and the transmit power of each femto mobile terminal is set according to the short-term path gains it reports. The proposed power control function achieves good results in terms of femto-macro performance trade-off and mobile terminal transmit power.

Inter-cell Interference Coordination for Femto Cells Embedded in a Moving Vehicle

This paper deals with inter-cell interference coordination ICIC techniques based on power control for moving femto cells. Power control is tuned depending on the femto cell position in order to take into account the impact of femto base station transmission onto macro base station terminals in the downlink and take into account the impact of femto base station terminal transmission onto macro base stations in the uplink, while maintaining good spectral efficiency within the femto cell. The proposed techniques are evaluated using system level simulations in a tramway scenario and compared with reference performance results without ICIC or with ICIC using orthogonal resources for femto cells and macro cells. In all cases, the proposed techniques outperform reference techniques.

SC-OFDM, a Low-Complexity Technique for High Performance Satellite Communications

Single-Carrier Orthogonal Frequency Division Multiplexing (SC-OFDM) is a transmission technique particularly suitable for satellite transmission due to its low envelope variations and to the advantages brought by its natural compatibility with zero roll-off. Moreover, low complexity per-carrier equalization is possible in the frequency domain. This paper proves the high performance of SC-OFDM transmission over satellite in different use cases and compares this performance with state of the art techniques such as DVB-SX transmission.

Hierarchical Modulations for Two-Level Transmission against Rain Fades in Satellite Broadcasting

A new family of 64ary hierarchical constellations for two level transmission is investigated in this paper. Constellation design is targeted to offer protection against rain fades for satellite broadcasting applications. This new family of constellations, derived from Amplitude Phase Shift Keying (APSK) designs, has low envelope fluctuations compared to other state of the art hierarchical constellations. It is also proven that it has superior performance compared to other types of two level transmissions such as time sharing.