Techniques for measuring and reducing signal misalignment in a dual connectivity environment are discussed herein. When using Non-Standalone Architecture (NSA), a device initially communicates with a network using a Long-Term Evolution (LTE) connection. After the LTE connection is established, an LTE base station may instruct the device to measure signal strength of a neighboring New Radio (NR) cell during a specified LTE measurement gap. When the NR cell is implemented by an indoor NR base station, the NR signal may not be sufficiently synchronized with the LTE signal and the device may be unable to measure the NR signal during the measurement gap. In these cases, the device can determine the frame timing difference between the LTE and NR signals, obtain an adjusted measurement gap that reduces any measurement gap misalignment, and attempt to measure the signal strength of the NR cell using the adjusted measurement gap.

This disclosure relates to orthogonal frequency division multiple access (OFDMA) communication in wireless local area networks (WLANs). According to some embodiments, a downlink OFDMA frame may be transmitted. An uplink OFDMA frame including acknowledgements associated with the downlink OFDMA frame may be received. The uplink OFDMA frame may be processed, in some instances including determining which devices receiving the downlink OFDMA frame transmitted an acknowledgement associated with the downlink OFDMA frame in the uplink OFDMA frame.

The Direct Synchronization of Synthesized Clock (DSSC) contributes a method, system and apparatus for reliable and inexpensive synthesis of inherently stable local clock synchronized to a referencing signal received from an external source. Such local clock can be synchronized to a referencing frame or a data signal received from wireless or wired communication link and can be utilized for synchronizing local data transmitter or data receiver. Such DSSC can be particularly useful in OFDM systems such as LTE/WiMAX/WiFI or Powerline/ADSL/VDSL, since it can secure lower power consumption, better noise immunity and much more reliable and faster receiver tuning than those enabled by conventional solutions.

Certain aspects of the present disclosure relate to methods and apparatus for generating synchronization signals for cell synchronization. Certain aspects of the present disclosure provide a method for wireless communication. The method generally includes determining a symbol index for transmitting a sequence; determining an amount of cyclical shift in one of a frequency domain and a time domain to apply to the sequence, wherein the amount of cyclical shift in the frequency domain is based on the sequence and the symbol index; shifting the sequence by the amount of cyclical shift; and transmitting the shifted sequence in a symbol corresponding to the symbol index.

The detection and validation of Secondary Synchronization Signal comprising generating a set of samples by performing DFT operation on a time domain LTE signal, wherein the signal comprising an LTE frame divided into an even half and odd half frame, First and second set of hypotheses from even samples in even and odd half frame are generated and third and fourth set of hypotheses from odd samples in even and odd half frame are generated using first and second hypotheses. Even half frame is selected as start of boundary of the frame when location of the peak of first hypotheses is smaller than that of second hypotheses or location of the peak of fourth hypotheses is smaller than that of third hypotheses. The physical layer cell identity is determined from the locations of the peak of the first, second, third and fourth set of hypotheses averaged over multiple frames.

A coarse timing method for a communication system is provided. The coarse timing method may include: calculating timing metric values for received signal samples using a self-correlation based timing metric function; calculating average timing metric values based on previous timing metric values; and determining whether there is a data frame based on the timing metric values and the average timing metric values.

In order to reduce ambiguity in NB-SSS and complexity of receiver processing, a transmitter apparatus generates an SSS, wherein the SSS signal comprises a sequence of OFDM symbols, wherein each symbol of the sequence of SSS symbols is mapped to a codeword symbol of an FEC code. Source symbols of the sequence of SSS symbols carry a PCID and frame timing information, and parity symbols of the sequence of SSS symbols introduce redundancy and coding gain. A receiver receives the NB-SSS over multiple OFDM symbols, each symbol of the SSS comprising a short ZC sequence with a combination of root index and cyclic shift. The apparatus derives path metrics using cross-correlation for each of the plurality of symbols, determines a candidate SSS source message based on the derived path metrics and coding constraints of FEC codewords, and identifies a PCID and timing information based on the candidate SSS source message.

There is provided an apparatus for detecting repetitive information in data packets communicated between a first node and a second node over a wireless network. The apparatus includes a processing circuitry. The processing circuitry is configured to: (a) collect samples of a data communication signal transmitted between said first node and the second node over said wireless network at a plurality of respective times; (b) group the collected samples into a plurality of sequences of samples; (c) combine the sequences of samples into at least one united signal; and (d) based on an analysis of the at least one united signal, provide a signal indicative of repetitive information in a plurality of data packets carried by said data communication signal.

According to an exemplary embodiment, a method of making a Hermetic transform to mitigate noise comprises: receiving over a channel signal frames comprising predetermined data and gaps comprising noise; framing the predetermined data; constructing a set of linear equations which relate a transfer function matrix of the channel to the predetermined data; determining the transfer function matrix by inverting the linear equations using a first pseudo inverse matrix; incorporating transfer function matrix into linear equations for a hermetic transform; and determining the hermetic transform using a second pseudo inverse matrix based on the predetermined data and the noise.

A symbol boundary in a data packet having a guard interval preceding a preamble having a predetermined sequence of symbols is detected by receiving a signal representing a data packet; sampling the received signal at a sampling rate; estimating channel impulse responses from a set of samples in dependence on the predetermined sequence of symbols of the preamble; determining an energy value for each of a plurality of windows of channel impulse responses, each of the windows corresponding to W number of consecutive samples, the energy value for each of the windows being indicative of the total energy associated with the channel impulse responses of that window; determining which of the windows has the greatest energy value; and identifying the earliest sample of the consecutive W samples in said determined greatest energy window, the earliest sample being indicative of a symbol boundary for the preamble.