Fractional Frequency Reuse Planning for WiMAX over Frequency Selective Channels

Abstract

Fourth generation broadband wireless access systems based on OFDMA/OFDM techniques operate in pointto-multipoint (PMP) configuration so that conventional cellular planning methods can be used for network design. As an alternative planning method fractional frequency reuse (FFR) strategy has been recently proposed for OFDMA/OFDM cellular systems such as WiMAX. For what concerns the determination of the system outage prediction, planning procedures for multi-carrier systems are usually based on bit error rate curves as a function of the average signal-to-interference plus noise ratio (SINR). Such curves are obtained after simulating the entire transmitter-receiver chain including multipath channel. However these approaches do not explicitly evidence the role of the number of M sub-carriers allocated to each user and are computationally intensive. In order to avoid such inconveniences we express the outage probability as a function of the effective SINR which is a function of the M SINRs (one for each sub-carrier). Such function already includes the decoding effects thus avoiding the re-simulation of the decoder behavior. Furthermore, this approach allows to explicitly evidence the role on planning of the number of subcarriers allocated for one user. For evaluation purposes we apply the procedure in a simple two cell FFR interference scenario. It is shown that the number of sub-carriers can play a significant role in the entire planning process i.e. the reuse distance can be lowered at the expense of an increased number of sub-carriers to be allocated per block.

On the suitability of public mobile networks for supporting train control/management systems

“…as in [6]- [8]) from those in [3] so that coverage requirements could be not guaranteed at all i.e. outage could be over the prescribed limits 1 and coverage holes could be present along the rail track.…”

Generalizing and optimizing fractional frequency reuse in broadband cellular radio access networks

“…In [16], an analytic model for estimating the throughput of FFR is presented. The idea of using analytic models instead of simulation to assess the signal-to-interferenceand-noise ratio (SINR) for FFR is adopted also in [17]. In [18], it is shown that, if FFR is performed in a distributed fashion, and each cell selfishly optimizes the assignment of resource to its own users, the system will converge to a Nash equilibrium.…”

Sequential frequency reuse with power control for OFDMA systems

“…In References 9–11, FFR for Mobile WiMAX is considered, which suggests time division of the available total bandwidth with different FRFs, i.e., cell‐edge bandwidth with FRF of 3 and cell‐center bandwidth with FRF of 1. So, downlink subframe is split into two parts: one for cell‐center users, and the other for cell‐edge users.…”