8/10/2019 CA With Per-CC Based Antenna Tilting in LTE-Advanced

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Carrier Aggregation with Per-CC based Different

Antenna Tilting in LTE-Advanced

Chang Min Park, PanKyu Suh, Duk Kyung Kim

Inha University, Incheon, South Korea

cmpark@inha.edu, sapchu@inha.edu, kdk@inha.ac.kr

Abstract Carrier aggregation (CA) technique in LTE-

Advanced has been proposed to aggregate two or more

component carriers (CC) for supporting high data rate

transmission over a wider bandwidth. In this paper, we propose

to apply per-CC based different antenna tilting to improve cell

edge throughput, where antenna electrical tilting angles of CCs

among eNB are set differently. We also propose a cell planning

for efficient per-CC different tilting and a cross-CC scheduling

algorithm to maximize the achievable performance gain.

Through intensive LTE-Advanced system level simulations, it isshown that the cell edge user throughput increases significantly

in linear and multi cells, by using the proposed scheme.

Index TermsLTE-Advanced; carrier aggregation; antenna;

electrical tilting; system level simulator;

I.INTRODUCTION

Due to recent increase in wireless devices such as smart

phones and tablet PCs, the wireless data traffic has been

increased dramatically. Currently, LTE has beencommercialized and numerous studies to achieve a higher data

rate have been conducted actively. Among LTE-Advanced

technologies, the Carrier aggregation (CA) that aggregatesmore than one component carriers (CCs) to support a wider

band has attracted much interest from operators and become

one of key features of 3GPP Release 10 [1,2].

The performance of the CA technique can be improved by

not only the expanded bandwidth but also some propermanagement of more than one CC. So far, a variety of CA

frequency combinations and CA deployment scenarios have

been suggested. In this paper, we propose a per-CC based

different antenna electrical tilting to improve the performance

of CA technique. Furthermore, an efficient cell planning and a

cross-CC scheduling algorithm are suggested to furtherenhance the system performance, especially the cell-edge user

throughput. For performance evaluation, we develop an LTE-Advanced based system level simulator [3], where the average

user throughput and 5% user (a.k.a, cell edge user) throughput

can be investigated in linear cell and multi cell environments.

II.PROPOSED CASCHEME

A.Per-CC based different antenna tilting

In CA deployment scenarios, coverage is decided by carrier

frequencies of CCs [1]. However, the coverage can be also

controlled by antenna electrical tilting [4]. We propose a new

CA scheme based on per-CC based different antenna electrical

tilting.

Figure 1 shows the proposed per-CC based different tilting

with two CCs. Lets take a simple example; Provided that CC1

and CC2 operate in the same frequency band, CC1 of eNB1

can set a large tilting angle while CC2 is set with a small tilting

angle. Meanwhile the CC1 of its neighboring eNB has a small

tilting angle, while its CC2 is set a large tilting angle. Then,two antenna beams go across each other. Each eNB is aware of

information of neighboring cell, and the users are connected to

the eNB which has the strongest signals for each CC. With this

management, the interference from neighboring cell can becontrolled on per-CC base and therefore, the cell edge user

throughput is improved.

B.Proposed cell planing and cross-CC Scheduling Algorithm

In a linear cell environment, the tilting angle of the same

CC can be crossed between neighboring eNBs. In case of multi

cell, however, every cell is not able to form crossed beams with

neighboring cells. So, an additional cell planning needs to be

done among neighboring 3 sectors so that they don t have the

same antenna tilting.

We propose a cross-CC scheduling algorithm to efficiently

manage the radio resource available over multiple CCs in the

proposed CA scheme. In CA proportional fair (PF) scheduling,resource allocation for the primary CC is conducted and theupdated data rate is informed to the secondary CC. And then,

the PF scheduling is performed for the secondary CC, by

taking into account the updated information after finishing the

scheduling for the primary CC. With the same antenna titling

for CCs, the order of scheduled CC has not been a concern for

the performance. However, in the proposed per-CC based

different antenna tilting, the coverage is decided according to

antenna electrical tilting. We propose to search for the CC with

the smallest coverage cell, whose antenna electrical tilting is

Fig. 1. Proposed per-CC based different antenna tilting

2013 19th Asia-Pacific Conference on Communications (APCC), Bali - Indonesia

978-1-4673-6050-0/13/$31.00 2013 IEEE 237

8/10/2019 CA With Per-CC Based Antenna Tilting in LTE-Advanced

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