Uplink MIMO Heterogeneous Network Interference Alignment Algorithm

In recent years, communications industry penetration into the user's daily life from all aspects, number of mobile phones, computers and other intelligent terminals show rapid growth. However, the traditional cellular network has been unable to meet the needs of a large number of intelligent terminals for access to the network, Therefore, by deploying a smaller transmit power and coverage of micro base stations within the coverage of the macro base station to increase capacity, Such regions consisting of different sizes, and have overlapping coverage areas called hybrid network of heterogeneous networks(Het Net). Heterogeneous networks can effectively achieve spatial multiplexing and expand system capacity cellular networks, and gradually become the mainstream of network deployment structure.With the rapid development of communication technology, the user demand for data transfer rate increasing, in addition to the introduction of heterogeneous network to increase system capacity, it is also an urgent need corresponding interface technology to enhance network data transfer speed as much as possible, Thus, the multi-antenna systems MIMO technology MIMO(Multiple-Input Multiple-Output) has been a great concern, MIMO antenna technology by simultaneously increasing the number of the transmitter and the receiver increases, in order to fully utilize space resources, greatly improve the system channel capacity, and does not change the premise of the spectrum resource usage and improve antenna transmit power down the communication quality. However, when multiple users share the channel resources at the receiving end user will be interference from other neighboring cells, these losses would seriously interfere with the communication quality of the user, thereby reducing the performance of the entire communication system, MIMO network in order to solve the serious interference problems, all kinds of interference alignment scheme came into this program by transmitting and receiving ends of the signal processing to the interference alignment to a smaller subspace, and the remaining space for the larger child transmission of the useful signal, to achieve the user high-speed data transmission needs.For uplink MIMO heterogeneous network, we use technology to improve the capacity of interference alignment system and the concept of freedom to measure the capacity of thesystem. This paper proposes a progressive interference alignment scheme, the interference alignment scheme can increase the degree of freedom of the system up, you can reach the lower bound of maximum freedom, and to be proved by the simulation results. Subsequently, this paper proposes a system up to maximum freedom upper bound. Since the lower and upper bounds of this article does not coincide up to maximum freedom, so the specific value of the uplink MIMO heterogeneous network up to the maximum degree of freedom is still an open problem.