What essential technology must be deployed to enable reliable communication for a lander on the Moon's far side?

A dedicated relay satellite positioned at the Earth-Moon Lagrange point L2

Landing a spacecraft on the far side introduces a major technical obstacle related to communications because the Moon itself blocks the direct line-of-sight radio transmissions necessary to communicate with mission control on Earth. To overcome this inherent communication blackout, future missions require an orbital relay system. This relay is specifically proposed to be a dedicated satellite situated at the Earth-Moon Lagrange point L2. This orbital intermediary position allows the satellite to maintain constant visibility of both the lander on the far side and mission control on Earth, effectively bouncing signals between the two points.