Coherent frequency hopping multiple access (CFHMA) with multiuser detection for mobile communication systems

Frequency-hop multiple-access systems with limited per-hop multi-user detection

“…Because each symbol is transmitted on multiple hops, a two-stage receiver attempts to use knowledge of the hopping patterns to cancel known interference. An example of a third approach is provided in [8] in which a spreading sequence is applied to the modulation of each hop. Each user has a different spreading sequence, and the receiver uses this knowledge to identify the signals from different users.…”

Reliable Adaptive Modulation and Interference Mitigation for Mobile Radio Slow Frequency Hopping Channels

“…Fading prediction methods for mobile radio channels were shown to enable adaptive modulation AM [1][2][3] in narrowband, Orthogonal Frequency Division Modulation (OFDM), adjacent frequency and Multiple Input Multiple Output (MIMO) fading channels in, e.g., [4][5][6][7][8]10,[25][26][27]. In this letter and [9,11,24], we explore AM aided by the Long range prediction (LRP) for Slow Frequency Hopping (SFH) spread spectrum mobile radio systems that employ coherent detection [13,15]. We propose to predict the channel coefficients in the next hopping frequency of SFH systems based on a number of past fading observations from previous hopping frequencies.…”

Enabling adaptive modulation and interference mitigation for slow frequency hopping communications

“…If σ is 10µs, the frequency separation has to decrease to 10 KHz to obtain good performance. In realistic SFH systems [9], the symbol rate is on the order of tens of Ksps. Thus, the frequency separation of SFH systems is often less than 100 KHz.…”

“…In this paper, we explore adaptive transmission aided by the LRP for slow frequency hopping (SFH) systems that employ coherent detection [9]. By exploiting the correlation between different frequencies, we propose to predict the channel coefficients in the next hopping interval of SFH systems based on a number of past fading observations from previous hopping intervals [7].…”