An important aspect of any channel assignment algorithm should be balancing the performance of uplink and downlink. Differences in receiver performance, diversity and transmit power used at mobiles and base stations are potential sources of imbalance. In addition, there is a fundamental asymmetry between uplink and downlink interference caused by the locations of mobiles and base statiams. We i...

We further describe an implementation of this system that uses an array of 32 antennas to communicate with 32 single-antenna clients simultaneously on the same frequencies between 512-608 and 614-698 MHz. At close range, all 32 links achieve the full PHY data rate, both uplink and downlink, with less than 1% Block Error Rate on each link. The total system rate is 3.8 Gb/s. The system spectral e...

As a mainstream technology in the 4G systems, TD-LTE (Time Division-Long Term Evolution) introduces Femto nodes to improve spectral efficiency per unit area. However, inter-cell cross-slot interference and uplink/downlink configuration are the key problems in TDD (Time Division Duplexing) system. In the paper, a traffic adaptation scheme with consideration of traffic demands and interference le...

Due to the dominance of the downlink traffic in Wireless Local Area Networks (WLANs), a large number of previous research efforts have been put to enhance the transmission from the Access Point (AP) to stations (STAs). IEEE 802.11ac, the amendment for next generation WLANs, will support MultiUser Multiple-Input Multiple-Output (MU-MIMO) in the downlink, which is considered as one of the key tec...

IEEE 802.16 mesh mode defines routing tree for transmitting data in centralized scheduling but it does not define any explicit proposal for combining uplink and downlink subframes. Deploying combined uplink and downlink subframes on the centralized scheduling scheme can be more flexible and utilization is improved. However, existing interferences among the transmission of neighboring nodes lead...

This paper develops an optimization framework for self-organizing networks (SON). The objective is to ensure efficient network operation by a joint optimization of different SON functionalities, which includes capacity, coverage and load balancing. Based on the axiomatic framework of monotone and strictly subhomogeneous function, we formulate an optimization problem for the uplink and propose a...

OFDMA is the access scheme used in the third and fourth generation wireless cellular networks. Proper allocation of bandwidth and power is essential for ensuring the optimal performance and utilization of the resources in the OFDMA based cellular networks. The resource allocation in uplink direction and downlink directional will need different approaches. In uplink direction, different categori...

A main challenge in providing connectivity to the low altitude unmanned aerial vehicles (UAVs) through existing cellular network arises due to the increased interference in the network. The increased altitude and favourable propagation condition cause UAVs to generate more interference to the neighbouring cells, and at the same time experience more interference from the downlink transmissions o...

We propose a combined uplink/downlink opportunistic scheduling algorithm for infrastructure WLANs. In the presence of both uplink and downlink flows, an infrastructure WLAN suffers from the uplink/downlink unfairness problem which severely decreases the throughput of the access point (AP). We resolve the unfairness by maintaining a separate queue and a backoff timer for each associated mobile s...

Radio planning and coverage optimization are critical issues when deploying and expanding third generation cellular systems. We investigate mixed integer programming models for locating and configuring base stations in UMTS networks so as to maximize coverage and minimize installation costs. The overall model considers both uplink and downlink directions, that we studied separately in Amaldi et...