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Abstract. Heterogeneous cellular networks, due to its multi-tier topological structure, provide significant improvements in terms of increased data rates and cell coverage. However, there are important intra-tier and inter-tier interference management problem to be solved. In this paper, we model a two-tier uplink heterogeneous network, which include a macrocell and K overlaid femtocells. Meanwhile we constitute a heterogeneous configuration that each femto BS is equipped with two antennas and the macro BS is equipped with 2 2antennas. We proved that the sum-DoF outer bound of the network is 2 4 4 K K A , and the DoF outer bound for the femtocell and macrocell is 2 4 K A K A and 4 A K A respectively. Moreover, we present the achievable scheme, which is based on interference alignment. The simulation results show that the sum rate of the whole HetNet increases as the number of macro BS's antennas increases.

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This paper analyzed the development course, present situation and trend of traditional satellite communication system which can provide internet broadband access and emerging satellite internet constellation. Considering the unique advantages of the geostationary earth orbit (GEO) and low earth orbit (LEO) satellite system and our country's national conditions, the concept of GEO-LEO hybrid satellite internet constellation is put forward, which provides the construction suggestions for our country's development of satellite internet constellation.

In this paper, a Mobility Pattern Adaptive Resource Combinatorial Optimization (MPARCO) algorithm is developed for mobility-aware STDMA MAC protocols in multi-hop wireless networks. The underlying problem entails the optimal joint link scheduling combined with the simultaneous assignment of transmit power levels and data rates across active mobile links. We develop a mathematical formulation for maximizing throughput and/or power efficiency under corresponding constrains. Then, we solve the problem with Discrete Dynamic Programming (DDP) depending on different mobility patterns. Finally, based on the solution, we propose our low complexity distribute MPARCO strategy which can be generically embedded into any existing mobility-aware STDMA MAC protocol.