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Firm technological responses to regulatory changes: A longitudinal study in the Le Mans Prototype racing
Despite the critical role of regulations on competition and innovation, little is known about firm responses and related effects on performance under regulatory contingencies that are permissive or restrictive. By longitudinally investigating hybrid cars competing in the Le Mans Prototype racing (LMP1), we counter-intuitively suggest that permissive regulations increase technological uncertainty and thus decrease the firms’ likelihood of shifting their technological trajectory, while restrictive regulations lead to the opposite outcome. Further, we suggest that permissive regulations favour firms that innovate their products by sequentially upgrading core and peripheral subsystems, while restrictive regulations—in the long term— favour firms upgrading them simultaneously. Implications for theory and practice are discussed
Interference Management in Heterogeneous Networks with Blind Transmitters
Future multi-tier communication networks will require enhanced network
capacity and reduced overhead. In the absence of Channel State Information
(CSI) at the transmitters, Blind Interference Alignment (BIA) and Topological
Interference Management (TIM) can achieve optimal Degrees of Freedom (DoF),
minimising network's overhead. In addition, Non-Orthogonal Multiple Access
(NOMA) can increase the sum rate of the network, compared to orthogonal radio
access techniques currently adopted by 4G networks. Our contribution is two
interference management schemes, BIA and a hybrid TIM-NOMA scheme, employed in
heterogeneous networks by applying user-pairing and Kronecker Product
representation. BIA manages inter- and intra-cell interference by antenna
selection and appropriate message scheduling. The hybrid scheme manages
intra-cell interference based on NOMA and inter-cell interference based on TIM.
We show that both schemes achieve at least double the rate of TDMA. The hybrid
scheme always outperforms TDMA and BIA in terms of Degrees of Freedom (DoF).
Comparing the two proposed schemes, BIA achieves more DoF than TDMA under
certain restrictions, and provides better Bit-Error-Rate (BER) and sum rate
performance to macrocell users, whereas the hybrid scheme improves the
performance of femtocell users.Comment: 30 pages, 18 figure
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