Articles » 6G MAC Security: Intelligent Scheduling & Resource Allocation

6G MAC Security: Intelligent Scheduling & Resource Allocation

6g resource allocation scheduling mac security wireless security physical layer physical layer security

Introduction : In the architecture of 6G security, the Physical Layer (PHY) provides the raw tools for protection like beamforming and artificial noise. However, it is the MAC Layer that acts as the “Brain” or “Gatekeeper.”

Through Intelligent Resource Allocation (RA) and Scheduling, the MAC layer decides who gets to transmit, when they transmit and how much power they use. By optimizing these decisions specifically for secrecy rather than just speed, the network can physically isolate eavesdroppers. This is known as the Cross Layer Security approach.

Following some of the techniques implemented by MAC layer to provide physical layer security (PLS) in 6G networks.

Security aware scheduling

  • In this technique, Base Station estimates channel quality of legitimate user and if possible, nearby eavesdropper’s channel quality too.

  • For example, if there are multiple users say user-A and user-B. Also assume there is an eavesdropper by name “Eve”.

    • Even if user-A signal is strong enough but there is an eavesdropper detected nearby or has correlated channel, Scheduler might deny them resources.
    • Instead, it schedules user-B whose channel is uncorrelated with Eve’s channel.

  • By scheduling transmission only when the legitimate link is mathematically superior to the wiretap link, the network guarantees a positive Secrecy Rate.

  • Traditional scheduler asks : “Who has the best channel?”

  • In 6G Scheduler asks : “Who has the best channel relative to the eavesdropper?”

Intelligent Power Allocation

  • In traditional power allocation , power is provided to best channels. In Secure Power Allocation, power is provided to channels where gap between legitimate receiver (Bilal) and eavesdropper (Eva) is wide enough. This will ensure that power is not picked up by Eve.
  • MAC layer decides power split ratio as per threat level. For example, 70% power to data signal and 30% to artificial noise planned to be injected towards Eve.

Subcarrier Allocation in OFDMA

  • 6G relies on Orthogonal Frequency Division Multiple Access (OFDMA) which splits the signal into many sub channels (i.e. subcarriers).
  • As we know wireless channel suffers from frequency selective fading in which some frequencies are received in good signal strength where as some are faded due to attenuation.
  • 6G adjusts frequency assignments due to OFDMA nature such that legitimate receiver always get good subcarriers with higher strength while eavesdropper receives poor signal subcarriers. Due to this, eavesdropper will not be able to decode the symbols.

Optimization metrics for 6G

To make decisions, MAC layer of 6G optimizes certain 6G specific parameters as follows.

  • Maximizing secrecy rate
  • Minimizing secrecy outage probability
  • Maximizing secure energy efficiency

Handling heterogenity of 6G

The biggest challenge in 6G is the diversity of services. A secure scheduling algorithm in the MAC layer must handle conflicting requirements.

  • For IoT (mMTC): The scheduler prioritizes low power consumption over high data rates, using lightweight hopping patterns to avoid jammers.
  • For Autonomous Driving (uRLLC): The scheduler prioritizes latency. It cannot wait for the “perfect” secure channel, so it may aggressively allocate power to artificial noise to create immediate security bubbles.

Conclusion: By moving security logic into the MAC Layer, 6G networks stop treating security as an afterthought (encryption) and start treating it as a resource. Through Intelligent Scheduling, the network ensures that data is only transmitted when physics of the environment favors the legitimate user. This process effectively keeps the eavesdropper out of conversation before single bit is decoded.