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4th Generation Synchronization

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Wireless communication imposes immense challenges on receiver design in case the transmitter and receiver are not synchronized. Strongly centralized network topologies such as cellular communication networks rely on high-quality hardware at the base transceiver station (BTS). This allows the network to be in sync with a common external signal (such as GPS). On the Mobile Station (MS) side, however, it cannot be guaranteed that such an external common clock signal is available at all times. Therefore, the BTS transmits synchronization data which allows the MS to synchronize in time and frequency to its serving BTS. Each cellular standard (GSM, UMTS, LTE) has its own set of synchronization signals. In this work, the case for LTE and LTE-Advanced shall be analyzed.

Project Description

LTE synchronization consists of 4 parts:

  1. LTE center frequency detection.
  2. OFDM symbol timing and fractional frequency offset detection.
  3. LTE specific Primary Synchronization Sequence (PSS) detection.
  4. LTE specific Secondary Synchronization Sequence (SSS) detection.

During this project, the student is asked to find a complete synchronization approach for the LTE system and test it on an RF/FPGA testbed. The testbed includes an RF chip connected to an FPGA which in turn is connected to a PC.

A handful of publications dedicated to LTE synchronization offer solutions to parts of the problem only. In particular, [1] only offers a solution for FDD systems using normal cyclic prefix (CP). It even omits the fact that the first CP within an LTE slot is longer that the remaining CPs. This discrepancy is covered in [2], where also the extended CP is considered. Even though [2] states that an extension to TDD systems is straightforward, many details have to be considered for a hardware implementation. At least in [3] a dual mode receiver (FDD and TDD) is considered and a solution is offered for SSS detection. All previously mentioned publications assume a priori knowledge of the LTE center frequency. [4] addresses this issue for TDD systems only, where as [5] offers a solution for FDD and TDD center frequency detection.

Status: In Progress

Student: Elis Nycander (msc15f3)
Supervision: Benjamin Weber, Sandro Belfanti


Qiuting Huang


[1] K. Manolakis, D.M. Gutierrez Estevez, V. Jungnickel, W. Xu, and C. Drewes. A Closed Concept for Synchronization and Cell Search in 3GPP LTE Systems. In Wireless Communications and Networking Conference, 2009. WCNC 2009. IEEE, pages 1–6, April 2009.

[2] W. Xu and K. Manolakis. Robust Synchronization for 3GPP LTE Systems. In Global Telecommunications Conference (GLOBECOM 2010), 2010 IEEE, pages 1–5, Dec 2010.

[3] Jung-In Kim, Jung-Su Han, Hee-Jin Roh, and Hyung-Jin Choi. SSS Detection Method for Initial Cell Search in 3GPP LTE FDD/TDD Dual Mode Receiver. In Communications and Information Technology, 2009. ISCIT 2009. 9th International Symposium on, pages 199–203, Sept 2009.

[4] H. Xu, R.N. Challa, and H.A. Mahmoud. Frequency Scan Method for Determining the System Center Frequency for LTE TDD, September 6 2013. WO Patent App. PCT/US2013/028,674.

[5] T. Erpek, K. Steadman, R. Krishnan, and Qiao Chen. LTE Signal Classification and Center Frequency Detection Without Priori Information. In Dynamic Spectrum Access Networks (DYSPAN), 2012 IEEE International Symposium on, pages 299–304, Oct 2012.