In this letter, we propose a fast dynamic slot assignment (F-DSA) protocol to reduce timeslot access delay of a newly arrived node in ad hoc networks. As there is no central coordinator, a newly arrived node needs separate negotiation with all the neighboring nodes for assigning slots to itself. Thus, it may result in network join delay and this becomes an obstacle for nodes to dynamically join and leave networks. In order to deal with this issue better, F-DSA simplifies the slot assignment process. It provides frequent opportunities to assign slots by using mini-slots to share control packets in a short time. Numerical analysis and extensive simulation show that F-DSA can significantly reduce the timeslot access delay compared with other existing slot assignment protocols. In addition, we investigate the effect of the mini-slot overhead on the performance.

Bluetooth is a common wireless technology that is widely used as a connection medium between various consumer electronic devices. The receivers mostly adopt the Viterbi algorithm to improve a bit error rate performance but are hampered by heavy hardware complexity and computational load due to a coherent detection and searching for the unknown modulation index. To address these challenges, a non-coherent maximum likelihood estimation detector with an eight-state Viterbi is proposed for Gaussian frequency-shift keying symbol detection against an irrational modulation index, without any knowledge of prior information or assumptions. The simulation results showed an improvement in the performance compared to other ideal approaches.

An AGC Applebaum array, which is a modified Applebaum array employing an automatic gain controller (AGC), is proposed. When the eigenvalues of the input covariance matrix of an array system are spread by orders of magnitude, conventional adaptive arrays are unable to remove all the interference signals quickly. The proposed array increases the cross-correlation between the low-power interference signals at the array input and output through the use of an AGC block in the feedback loop. As a result, the weight vector is adapted for the removal of both low-power and high-power interference signals. Computer simulations were performed to demonstrate that the proposed array can produce high output signal to interference plus noise ratio (SINR) with a fast convergence speed.