A 40nm 4-downlink and 2-uplink RF Transceiver Supporting LTE-
Advanced Carrier Aggregation
Abstract—A multi-band multi-mode LTE-Advanced (LTE-
A) transceiver is demonstrated in this paper. There are 4
receivers (RX) to support inter-band and intra-band
downlink (DL) carrier aggregation (CA) with 256QAM
modulation. The RX noise figure (NF) is better than 2.5 dB for
RF frequencies < 2.7 GHz and the NF is 3.5 dB in the 5 GHz
band. In addition, there are two transmitters (TX) to support
inter-band and intra-band uplink (UL) CA with 64QAM
modulation. The TX EVM is 1.59% in the 3.5 GHz band. The
system architecture and circuit techniques to overcome the
4RX/2TX CA spurs and interferences are described in this
paper. It is shown that there is no unwanted CA spur in the
signal bandwidth.
Index Terms—LTE-Advanced, carrier aggregation, LTE,
spur, isolation, transceiver
I. INTRODUCTION AND TOP PLAN
In recent years, LTE-A has evolved rapidly to increase
the data throughput by aggregating more and more carriers.
Several papers have reported the latest CA developments
[1-3]. In this paper, a RFIC that supports up to 4 DL
inter/intra-band CA and 2 UL inter/intra-band CA is
demonstrated as shown in Fig. 1. This work integrates two
individual RFICs in a single package to achieve the best CA
performance. Each RFIC consists of two direct conversion
receivers, a direct conversion transmitter and a TX
detection path for power measurement. This transceiver
supports 0.6 ~ 6 GHz RX DL and 0.6 ~ 3.8 GHz TX UL.
The number of bands has increased rapidly from GSM to
LTE communication systems. GSM had only 4 bands while
LTE has increased to more than 40 bands. In LTE-A, these
bands can form hundreds of CA combinations. This work
supports all CA combinations defined in the 3GPP standard
(3GPP TS 36.101 V14.3.0) including 16 sets of contiguous
CA (CCA), 13 sets of intra-band non-contiguous CA
(NCCA), 137 sets of 2 ICA, 146 sets of 3 ICA, and 72 sets
of 4 ICA.
A CA example is shown in Fig. 2. This example supports
B1/B3/B7/B8/B20/B42 European bands; and among the
supported CA combinations, there are 15 sets of 2 inter-
band CA (ICA), 20 sets of 3 ICA, and 15 sets of 4 ICA.
LNA, mixer and LO architectures in this work are designed
with enough flexibility to support any of the CA
combinations in Fig. 2. It is worthwhile mentioning that this
design could be extended to cover the worldwide CA
scenarios.
RX1
Primary
+Diversity
TX1
TX
Detection
Path 1
TX Det.
IQ1
TXIQ1
RXIQ2RXIQ1
RX2
P+D
Top
Misc.
Circuits
Die-1
Die-2
RXIQ3 RXIQ4
TXIQ2
TX Det.
IQ2
TX2
TX
Detection
Path 2
RX3
P+D
RX4
P+D
BSI,
CLK
Fig. 1. Transceiver block diagram (4RX/2TX Transceiver)
Fig. 2. CA combinations for popular bands in Europe.
Conventional receiver design focuses only on the single-
path RX performance such as NF and linearity for LTE
bands while LTE-A receiver design needs to consider RX
desensitization caused by the spur coupling between
multiple receivers and transmitter paths. The
intermodulation products (IMD) of 4RX and 2TX paths are
calculated and identified [4].
B1 B3
B7
B8B20
B42
2CA # :
3CA # :
4CA # :
MB MB
HB
LBLB
UHB
Tzung-Han Wu
1
, Yuan-Yu Fu
1
, Sheng-Che Tseng
1
, Ying-Tsang Lu
1
, Yangjian Chen
2
,
Chien-Shan Chiang
1
, Zong-You Li
1
, Bo-Yu Lin
1
, Min-Hua Wu
1
, Jui-Chih Kao
1
, Tzu-Yu Yeh
1
,
Li-Shin Lai
1
, Chao-Wei Wang
1
, Chih-Hao Eric Sun
1
, Yen-Horng Chen
1
, Chinq-Shiun Chiu
1
,
Shih-Chieh Yen
1
, Guang-Kaai Dehng
1
, George Chien
3
, and Bernard Tenbroek
2
1
MediaTek, Taiwan
2
MediaTek, UK
3
MediaTek, Singapore
978-1-5386-4545-1/18/$31.00 © 2018 IEEE 2018 IEEE Radio Frequency Integrated Circuits Symposium
RTU2B-5
316