Propagation-delay based interference alignment with extra time-slot for 3×3 X channel

Abstract

For 3×3 X channels, the theoretical degree of freedom of 9/5 can only be achieved by asymptotic interference alignment, which requires infinite resources to approximate, which is impossible to implement in practice. In a single antenna node scenario, the interference alignment scheme can be designed in the time domain. In order to minimize the transmission delay, it is considered to implement the transceiving processing of the message by increasing the cost of one extra time-slot. The 3×3 X channel message transmission is realized by reasonably scheduling the transmission time slot of the message and matching the propagation delay between the selected transmitter and the receiver. The specific transmission and reception schemes are given by the representation method of the cyclic polynomial, and the degree of freedom reaches 3/2. And comparing the total number of successfully transmitted messages, the result transmission efficiency is better than the time division multiple access scheme. Further, the feasibility conditions of the scheme in Euclidean space are derived, and the range requirements of each node arrangement are indicated.

Keywords

• interference alignment
• degree of freedom
• propagation-delay
• 3×3 X channel
• extra time-slot