Question
Asked 6th Dec, 2014

Can single antenna be used for transmission and reception both, considering the node as full duplex?

A mobile node (GSM) is equipped with single monopole antenna operating in full-duplex mode (uses different frequencies for transmission and reception). In fact, the node is half-duplex. In literature, many works are discussed regarding the analysis of full-duplex node equipped with two different antennas for transmission and reception. Can it be possible for this purpose to use full-duplex node having single antenna?

Most recent answer

1st Sep, 2015
Shahriar Shirvani Moghaddam
Shahid Rajaee University
Single antenna can be used for duplex or semiduplex scenarios. In full-duplex if you use a duplexer between TX-RX and antenna, you can send and receive simultaneously in different frequencies. For TDD case, in a slot time you can send and in the another slot time you can receive. For TDD transmission, transmitting and receiving frequencies are the same.  

Popular answers (1)

9th Dec, 2014
Gert Cuypers
KU Leuven
Theoretically it is also possible to use the same antenna for reception and transmission *simultaneously*. This could be implemented using a circulator, i.e. a microwave device with three ports, which routes the signals from port 1 to 2, 2 to 3 and 3 to 1. By connecting the transmitter to port 1, the antenna to port 2 and the receiver to port 3, it is possible to transmit and receive simultaneously.
In practice this would not work very well. Unless the antenna has an extremely low return loss, some transmitted signal will leak to the receiver. Because the transmit power is much larger than the received power, the incoming signal would be completely drowned. But it is possible in theory.
7 Recommendations

All Answers (17)

6th Dec, 2014
Saso Tomazic
University of Ljubljana
Of course it can using different frequency band for tranmision and reception (FDM) or different time slots (TDM).
Saso
4 Recommendations
6th Dec, 2014
Amit Kumar Garg
Indian Institute of Information Technology Kota
Yes, generally these modules are called TRANSCEIVERS.
1 Recommendation
7th Dec, 2014
El Ouadih Abdelhakim
Université Mundiapolis
Actualy as for radar, it uses the same antenna but there is transmission period alternating with a receiving time. It's half duplex and the dissociation between transmission and reception (to avoid also receiving high power that can destruct the receiver) is garanted by an equipment that is called duplexer. For GSM use, technically the antenna functions in half duplex using decalled timeslots in different frequencies but the user that is a human being is senstive to timeslot value (~544 microseconds) will feel the GSM link as a full duplex and as a continuous one.
1 Recommendation
7th Dec, 2014
El Ouadih Abdelhakim
Université Mundiapolis
I said the user is NOT sensitive to tie
1 Recommendation
8th Dec, 2014
Arjav Bavarva
Marwadi Education Foundation’s Group of Institutions
Yes, almost in all communication system having one antenna is used for transmission and reception purpose. It can be done with the help of the device called duplexer. Also compare duplexer with diplexer. It is easily available on google. 
9th Dec, 2014
Amipara Manilal D
Balaji Institute of Engineering & technology, Junagadh
Lot of people has already answered as "YES" 7 it is true. Only one point I would like to add here is , Antenna point of view, it's Bandwidth with regards to frequency should be enough to accommodate Tx & Rx freq. (especially S11 & Gain). Additionally, very good duplexing unit to isolate/protect receiver from its own transmitting power, especially if it is very high 
2 Recommendations
9th Dec, 2014
Shahriar Shirvani Moghaddam
Shahid Rajaee University
It is possible in two modes, TDD and FDD. In TDD mode, transmitter and receiver have similar frequency but their active times are different. In this mode, When transmitter is active, receiver is off and vice versa. In FDD, it is needed to assign two different frequencies, one for transmission and other one for reception. In this case, we need duplexer as well as diplexer.
1 Recommendation
9th Dec, 2014
Gert Cuypers
KU Leuven
Theoretically it is also possible to use the same antenna for reception and transmission *simultaneously*. This could be implemented using a circulator, i.e. a microwave device with three ports, which routes the signals from port 1 to 2, 2 to 3 and 3 to 1. By connecting the transmitter to port 1, the antenna to port 2 and the receiver to port 3, it is possible to transmit and receive simultaneously.
In practice this would not work very well. Unless the antenna has an extremely low return loss, some transmitted signal will leak to the receiver. Because the transmit power is much larger than the received power, the incoming signal would be completely drowned. But it is possible in theory.
7 Recommendations
9th Dec, 2014
Alberto Giuseppe Perotti
Huawei Technologies
There have been and there are currently ongoing research activities on the implementation of true full-duplex transceivers (meaning that the same antenna is used for simultaneous transmission and reception in the same frequencies).
This paper, for example, describes a full-duplex WiFi transceiver design:
A more general approach is described here:
3 Recommendations
9th Dec, 2014
Elangovan Sundaram
ALL INDIA RADIO
Dear Gert Cuypers,
In circulator the reflected RF power due to antenna mismatch  also available at the port no 3.In VHF transmitters circulators are used between two amplifier stages with a non inductive resistor on Port 3 to kill the reflected power due to mismatch. Practically no antenna is ideal .So circulator can't be used in practical as stated in your suggestion.Any promlem with you Antenna tuning unit will kill the receiver front end by burning most of the active components.
Dear Amit Kumar Garg ,
In Transceiver a separate mechnical or preferably electronic switching circuits are built in for automatic change over.In transmit mode antenna will be connected to RF Amplifier output and in receiving mode connection changes to receiver front end. 
1 Recommendation
10th Dec, 2014
Shilpa Lambor
Vishwakarma Institute of Technology
Yes. You can use the same antenna as a transmitter and as a receiver. We then call it a transceiver. The data path to the antenna and from the antenna are separate. Modulation is performed before transmission and demodulation is performed after reception
1 Recommendation
10th Dec, 2014
Abhishek Goudar
Carnegie Mellon University
+1 Saso Tomazic
12th Dec, 2014
Liawas Barukang
Universiti Malaysia Sabah (UMS)
Silpa Lambor understood the question wrongly I see. Pawan was talking about simultaneity of transmitting and receiving signal from single antenna.
Antenna is a 'serial' device, by default transmission and reception are time slotted. Gert's explaination works well practically in transmission schemes where transmitted and received signals are of different center frequency, but still requires two separate antennas tuned to tx and rx frequency.
If tx and rx signal to an antenna is not time slotted, then whose signal is it in the antenna at an instantaneous time t?
5 Recommendations
12th Dec, 2014
Martin Haenggi
University of Notre Dame
You can achieve virtual fullduplex with a single antenna using the technique described in this paper:
2 Recommendations
13th Dec, 2014
Pawan Kumar
National Institute of Technology Rourkela
Thank you dear Martin.
And thanks to all for your erudite answers.
24th Dec, 2014
V. K. Singh
S R Group of Institutions(CEMT) Jhansi
An antenna diplexer or RF diplexer is a unit that in one application can be used to enable more than one transmitter to operate on a single RF antenna. Sometimes these units may be called antenna duplexers. Typically an antenna diplexer would enable transmitters operating of different frequencies to use the same antenna. In another application, an antenna diplexer may be used to allow a single antenna to be used for transmissions on one band of frequencies and reception on another band. Antenna diplexers find many uses.
In one common example an antenna diplexer or RF diplexer is used in a cellular base station to allow it to transmit and receive simultaneously.
1st Sep, 2015
Shahriar Shirvani Moghaddam
Shahid Rajaee University
Single antenna can be used for duplex or semiduplex scenarios. In full-duplex if you use a duplexer between TX-RX and antenna, you can send and receive simultaneously in different frequencies. For TDD case, in a slot time you can send and in the another slot time you can receive. For TDD transmission, transmitting and receiving frequencies are the same.  

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