Pyeong-Jung Song

The Design of a Dual-Polarized Small Base Station Antenna With High Isolation Having a Metallic Cube

A dual-polarized small base station antenna is presented that has a metallic cube and high isolation. The antenna is composed of a micro-strip feed line board, planar dipole radiators, micro-strip coupling feeds, a metallic cube, and a radome. The measured impedance bandwidth is 2.36-2.95 GHz at port-1 and 2.4-2.83 GHz at port-2. The proposed base station antenna has a high isolation of greater than 40 dB at the operating frequency. The measured peak gain is 9 dBi, and the cross polarizations are all less than 25 dB below the co-polarization level.

The Design of a Dual-Polarized Small Base Station Antenna with High Isolation Having Dielectric Feeding Structure

A dual-polarized small base station antenna with a dielectric feeding structure is presented. The proposed antenna is composed of a micro-strip feed line board, eight metallic shorting plates, four dielectric feed substrates, four metallic radiators, a metallic cube, and a radome. A wide impedance bandwidth of 20% (2.45 to 3.0GHz) is achieved. The proposed antenna has an isolation of greater than 50dB over the operating bandwidth. Details of the proposed antenna design, and the simulated and measured results are presented and discussed.

Impacts of joint packet scheduling for heterogeneous component carriers in multi-carrier systems

Component carriers (CCs) in a Long Term Evolution - Advanced (LTE-A) system are limited by maximum 100 radio bearers (RBs) on a 20 MHz CC due to a fixed 15 KHz subcarrier bandwidth. However it is able to be changed in the future, so that a study regarding heterogeneous CCs which have diverse RBs above 100 on a CC is needed at this moment. To support non-contiguous carrier aggregation (CA) with the these conditions, a heterogeneous joint CC packet scheduling algorithm interacting with a radio resource control (RRC) is considered in this paper. The performance of the joint CC packet scheduling algorithm on heterogeneous CCs with different channel characteristics has been analyzed and compared through computer simulations as well. According to the results, we found that an 800 MHz CC exhibits approximately 4 dB better channel gains than a 2.1 GHz CC. We also obtained a capacity increase of about 15-40% for a joint CC maximum rate (MR) algorithm and about 2-28 % for a joint CC proportional fair (PF) algorithm when the number of users is increased. On the other hand, in a round-robin (RR) scenario, we were unable to notice any differences between the independent CC and joint CC packet scheduling policies. Furthermore, looking at the impacts of different amounts of RBs on 800 MHz + 2.1 GHz CCs, we can conclude that a one-to-one RB ratio with respect to the MR, PF, and RR algorithms has a better performance compared to other cases, and thus, owing to the better channel gain, the smaller the RBs of the 800 MHz CC, the better the performance achieved.

Measurement of Inter-Frequency Small Cell in Heterogeneous Networks

Inter-frequency small cell deployments on hotspot locations are seen as a potential solution to offload macro user traffic to small cells. In order to discover inter-frequency small cells, macro user equipments (UE) are required to perform gap-assisted measurement. The currently existing short measurement periods can increase offloading, but at low UE speeds, it leads to unnecessarily measurement to scan neighbor cells and results in waste of UE battery. Long measurement periods are discussed in 3GPP to reduce UE power consumption. However, due to long measurement periods and consequently delayed cell discovery, inter-frequency mobility and offloading performance are degraded, especially at UE high speeds. In this paper, it is shown using simulation that mobility performance and the small cell dwelling time are degraded at high UE speeds when adopting the long measurement periods. Based the simulation results, it is proposed that applying the long measurement period is effective for low mobility UE to reduce the UE power consumption while keeping the acceptable handover failure rate and the offloading performance.