Fundamentals of dynamic frequency hopping in cellular systems

Abstract

We examine techniques for increasing spectral efficiency of cellular systems by using slow frequency hopping (FH) with dynamic frequency-hop (DFH) pattern adaptation. We first present analytical results illustrating the improvements in frequency outage probabilities obtained by DFH in comparison with random frequency hopping (RFH). Next, we show simulation results comparing the performance of various DFH and RFH techniques. System performance is expressed by cumulative distribution functions of codeword error rates. Systems that we study incorporate channel coding, interleaving, antenna diversity, and power control. Analysis and simulations consider the effects of path loss, shadowing, Rayleigh fading, cochannel interference, coherence bandwidth, voice activity, and occupancy. The results indicate that systems using DFH can support substantially more users than systems using RFH. Index Terms-Cellular, code-division multiple access (CDMA), dynamic channel allocation (DCA), dynamic channel assignment, EDGE, frequency hopping, orthogonal frequency-division multi-plexing (OFDM), spectral efficiency, wireless.

Minimum Cell Size for Information Capacity Increase in Cellular Wireless Network

“…The number of co-channel interfering cells in the first and second tier has been given [43,44], but there are no explanations or proof for how they were derived. Currently, conventional cellular system analysis is based on the assumption of first tier co-channel interference cells being active with other tier co-channel interfering cells being assumed to be negligible, because of the assumption of a large basic path loss exponent, lower microwave carrier frequency and bigger cell size radius [7].…”

Resource Allocation Algorithm with Dynamic Subcarrier Assignment in OFDMA-based Wireless Networks

“…As FH is done exclusively among the same quality subcarriers, there is no reduction in throughput and transmission rate of the system. Hopping pattern for FH is not pre-defined because it is determined dynamically based on the subcarriers' quality [14][15][16], [18]. The algorithm of subcarrier allocation is described in Section 3 in more details.…”

“…Additional frequency diversity is achieved with FH between subcarriers of the same quality to prevent system capacity degradation. Unlike other papers, FH is not limited to the pre-defined set of subcarriers only and hopping pattern is determined dynamically based on the subcarriers' quality [14][15][16].…”

“…The benefits of dynamic FH are compared to pseudorandom FH, assuming perfect signal measuring and no delay in signaling [15,16].…”

Double Hopping: A new approach for Dynamic Frequency Hopping in Cognitive Radio networks

“…Hopping sequence design for GSM is studied in [8], [9]. Dynamic frequency hopping in GSM is studied and compared to random hopping in [10]. Here, the frequency hopping pattern of a mobile is adapted based on measurements made at the base station and the mobile.…”