Deploying LTE networks in unlicensed spectrum requires us to move beyond coexistence mechanisms and understand the suitability of LTE's synchronous operation in a spectrum that is governed by asynchronous access principles. Our study reveals a fundamental conflict in LTE uplink access that arises between the scheduled nature of LTE's multi-user transmissions -- critical for leveraging the diversity (OFDMA) and multiplexing (multi-user MIMO) gains -- and the asynchronous nature of interference on the clients. The result is a significant loss in spectrum utilization and throughput that scales with the number of interfering terminals. To tackle this critical challenge on the LTE uplink, we propose Blu. Blu transforms today's LTE schedulers into speculative schedulers that leverage interference diversity across clients to intelligently over-schedule clients on the same spectral resources to prevent this utilization loss. Blu's challenges lie in how to over-schedule appropriate clients on the same resources without paying the penalty of collisions, while containing the exponential overhead incurred in measuring the required interference dependencies between clients. The under-pinning of Blu's design includes a novel mechanism to blue-print the very source of interference on LTE clients along with their dependencies, which allows for a constant, significantly reduced overhead. Blu can be realized in today's LTE base stations. Its realization in an enterprise environment with SDRs (hosting LTE release 10) reveals appreciable gains of 1.5-2x in both utilization and throughput over existing schemes for SISO and MU-MIMO transmissions in unlicensed spectrum.