preambles

n.

序( preamble的名词复数 )；绪言；（法令、文件等的）序文；前言

without preamble直截了当地，开门见山地，单刀直入地

Preambles
PREAMBLES
PREAMBLES
Energy-efficient reception of large preambles in MAC protocols for wireless sensor networks
Time and frequency synchronization for OFDM using PN-sequence preambles
Time and frequency synchronization for OFDM using PN-sequence preambles
Method and system for multi-antenna preambles for wireless networks preserving backward compatibility
Performance Evaluation of Impulse Radio UWB Networks Using Common or Private Acquisition Preambles
Maximum Likelihood Timing and Carrier Frequency Offset Estimation for OFDM systems with Periodic Preambles
Maximum Likelihood Timing And Carrier Frequency Offset Estimation For Ofdm Systems With Periodic Preambles