Distributed probabilistic-data-association-based soft reception employing base station cooperation in MIMO-aided multiuser multicell systems

Intercell cochannel interference (CCI) mitigation is investigated in the context of cellular systems relying on dense frequency reuse (FR). A distributed base-station (BS)-cooperation-aided soft reception scheme using the probabilistic data association (PDA) algorithm and soft combining (SC) is proposed for the uplink of multiuser multicell MIMO systems. The realistic 19-cell hexagonal cellular model relying on unity FR is considered, where both the BSs and the mobile stations (MSs) are equipped with multiple antennas. Local-cooperation-based message passing is used, instead of a global message passing chain for the sake of reducing the backhaul traffic. The PDA algorithm is employed as a low-complexity solution for producing soft information, which facilitates the employment of SC at the individual BSs to generate the final soft decision metric. Our simulations and analysis demonstrate that, despite its low additional complexity and backhaul traffic, the proposed distributed PDA-aided SC (DPDA-SC) reception scheme significantly outperforms the conventional noncooperative benchmarkers. Furthermore, since only the index of the possible discrete value of the quantized converged soft information has to be exchanged for SC in practice, the proposed DPDA-SC scheme is relatively robust to the quantization errors of the soft information exchanged. As a beneficial result, the backhaul traffic is dramatically reduced at negligible performance degradation

Uplink CoMP under a Constrained Backhaul and Imperfect Channel Knowledge

Coordinated Multi-Point (CoMP) is known to be a key technology for next generation mobile communications systems, as it allows to overcome the burden of inter-cell interference. Especially in the uplink, it is likely that interference exploitation schemes will be used in the near future, as they can be used with legacy terminals and require no or little changes in standardization. Major drawbacks, however, are the extent of additional backhaul infrastructure needed, and the sensitivity to imperfect channel knowledge. This paper jointly addresses both issues in a new framework incorporating a multitude of proposed theoretical uplink CoMP concepts, which are then put into perspective with practical CoMP algorithms. This comprehensive analysis provides new insight into the potential usage of uplink CoMP in next generation wireless communications systems.Comment: Submitted to IEEE Transactions on Wireless Communications in February 201

Path Loss Modeling for V2V Communication on a Slope

Path loss modeling for both regular and irregular terrains is still gaining significant attention from researchers. A sloped terrain is one specific kind of an irregular terrain that-as far as we are aware-has not been completely studied. Although some results have been published for slope path loss modeling in cellular communication, an adequate model for the case when the transmitter (Tx) and the receiver (Rx) both have low-height antennas and are located on or near a slope does not exist. In this paper, for complete analysis of such conditions, we consider four scenarios: 1) two vehicles are located at opposite ends of the slope; 2) one vehicle is on the slope, and the other vehicle is beyond the slope crest; 3) one vehicle is on the slope, and the other is away from the slope at the bottom; 4) both vehicles are on the slope. For scenarios 1 and 2, we have developed analytical path loss models. We have also made some corroborating measurements for scenario 1. Scenarios 3 and 4 are addressed by models already in the literature. Simulation results for two vehicles traveling toward, on, and then beyond a slope (a sequence of our scenarios) are also shown to illustrate how sloped-terrain path loss varies in contrast to the typical flat-earth condition. Our models for scenarios 1 and 2 add to the literature and can be used to numerically estimate path losses for vehicle-to-vehicle (V2V) communication over a slope