  The coexistence of heterogeneous sub-networks in 6G poses new security and
trust concerns and thus calls for a perimeterless-security model. Blockchain
radio access network (B-RAN) provides a trust-building approach via repeated
interactions rather than relying on pre-established trust or central
authentication. Such a trust-building process naturally supports dynamic
trusted services across various service providers (SP) without the need for
perimeter-based authentications; however, it remains vulnerable to
environmental and system unreliability such as wireless channel uncertainty. In
this study, we investigate channel unreliability in the trust-building
framework based on repeated interactions for secure wireless services. We
derive specific requirements for achieving cooperation between SP and client
via a repeated game model and illustrate the implications of channel
unreliability on sustaining trusted access services. We consider the framework
optimization to guarantee SP-client cooperation, given a worst-case channel
condition. Furthermore, we introduce the concept of cooperation region to
represent the robustness of the trust-building process and explore the maximum
cooperation area to enhance service resilience. Finally, we present simulations
to demonstrate the system performance over fading channels and verify our
results.
