Results

**11 - 16**of**16**### 1 A New Peak-to-Average Power-Ratio Reduction Algorithm for OFDM Systems via Constellation Extension

"... Abstract — Peak-to-average power-ratio (PAPR) reduction for OFDM systems is investigated in a probabilistic framework. A new constellation extension technique is developed whereby the data for each subcarrier are represented either by points in the original constellation or by extended points. An op ..."

Abstract
- Add to MetaCart

(Show Context)
Abstract — Peak-to-average power-ratio (PAPR) reduction for OFDM systems is investigated in a probabilistic framework. A new constellation extension technique is developed whereby the data for each subcarrier are represented either by points in the original constellation or by extended points. An optimal representation of the OFDM signal is achieved by using a de-randomization algorithm where the conditional probability involved is handled by using the Chernoff bound and the evaluation of the many hyperbolic cosine functions involved is replaced by a tight upper bound for these functions. The proposed algorithm can be used by itself or be combined with a selective rotation technique described in the paper and with other known algorithms such as the coordinate descent optimization and selective mapping algorithms to achieve further performance enhancements at the cost of a slight increase in the computational complexity. When compared with other existing PAPR-reduction algorithms, the enhanced algorithm offers improved PAPRreduction performance and improved computational complexity although the transmit power is increased somewhat. Index Terms — OFDM, peak-to-average power-ratio reduction, constellation extension, de-randomization.

### On the Perfect Cyclically Conjugated Even and Odd Periodic Autocorrelation Properties of Quaternary Golay Sequences

"... A sequence is called perfect if its autocorrelation function is a delta function. In this paper, we give a new definition of autocorrelation function: generalized even and odd periodic autocorrelation, and generalized even and odd periodic cyclically conjugated autocorrelation. In particular, we stu ..."

Abstract
- Add to MetaCart

(Show Context)
A sequence is called perfect if its autocorrelation function is a delta function. In this paper, we give a new definition of autocorrelation function: generalized even and odd periodic autocorrelation, and generalized even and odd periodic cyclically conjugated autocorrelation. In particular, we study a special case of autocorrelation function called cyclically conjugated autocorrelation function. As a result, we present several classes of perfect cyclically conjugated even periodic and odd periodic autocorrelation of quaternary Golay sequences. We also considered such perfect property for 4q-QAM Golay sequences, q ≥ 2 being an integer. Those proposed sequences could be used for synchronization and detection if the time delay is known. Index Terms. Golay sequence, quadrature amplitude modulation (QAM), cyclically conjugated even periodic autocorrelation, cyclically conjugated odd periodic autocorrelation. 1

### Optimal Odd-Length Binary Z-Complementary Pairs

, 2013

"... A pair of sequences is called a Golay complementary pair (GCP) if their aperiodic auto-correlation sums are zero for all out-of-phase time shifts. Existing known binary GCPs only have even-lengths in the form of 21026 (where ; ;
are non-negative integers). To fill the gap left by the odd-lengths, ..."

Abstract
- Add to MetaCart

A pair of sequences is called a Golay complementary pair (GCP) if their aperiodic auto-correlation sums are zero for all out-of-phase time shifts. Existing known binary GCPs only have even-lengths in the form of 21026 (where ; ;
are non-negative integers). To fill the gap left by the odd-lengths, we investigate the optimal odd-length binary pairs which display the closest correlation property to that of GCPs. Our criteria of “closeness ” is that each pair has the maximum possible zero-correlation zone (ZCZ) width and minimum possible out-of-zone aperiodic auto-correlation sums. Such optimal pairs are called optimal odd-length binary Z-complementary pairs (OB-ZCP) in this paper. We show that each optimal OB-ZCP has maximum ZCZ width of (N+1)=2, and minimum out-of-zone aperiodic sum magnitude of 2, where N denotes the sequence length (odd). Systematic constructions of such optimal OP-ZCPs are proposed by insertion and deletion of certain binary GCPs, which settle the 2011 Li-Fan-Tang-Tu open problem positively. The proposed optimal OB-ZCPs may serve as a replacement for GCPs in many engineering applications where odd sequence lengths are preferred. In addition, they give rise to a new family of base-two almost difference families (ADF) which are useful in studying partially balanced incomplete block design (BIBD).

### New Methods to Construct Golay Complementary Sequences Over the QAM Constellation

"... Abstract. In this paper, based on binary Golay complementary se-quences, we propose some methods to construct Golay complementary sequences of length 2n for integer n, over theM2-QAM constellation and 2M-Q-PAM constellations,where M = 2m for integer m. A method to judge whether a sequence constructe ..."

Abstract
- Add to MetaCart

(Show Context)
Abstract. In this paper, based on binary Golay complementary se-quences, we propose some methods to construct Golay complementary sequences of length 2n for integer n, over theM2-QAM constellation and 2M-Q-PAM constellations,where M = 2m for integer m. A method to judge whether a sequence constructed using the new general offset pairs over the QAM constellation is Golay complementary sequence is proposed. Base on this judging rule, we can construct many new Golay complementary sequences. In particular, we study Golay complementary sequences over 16-QAM constellation and 64-QAM constellation,many new Golay complementary sequences over these constellations have been found.

### Golay Complementary Sequences Over the QAM Constellation

"... Abstract. In this paper,we present new constructions for M2-QAM and 2M Q-PAM Golay complementary sequences of length 2n for inte-ger n, where M = 2m for integer m. New decision conditions are pro-posed to judge whether the sequences with offset pairs proposed by Ying Li are Golay complementary, and ..."

Abstract
- Add to MetaCart

(Show Context)
Abstract. In this paper,we present new constructions for M2-QAM and 2M Q-PAM Golay complementary sequences of length 2n for inte-ger n, where M = 2m for integer m. New decision conditions are pro-posed to judge whether the sequences with offset pairs proposed by Ying Li are Golay complementary, and with the new decision conditions, we prove the conjecture 1 and point out some drawbacks in conjecture 2 proposed by Ying Li. We describe a new offset pairs and construct new 64-QAM Golay sequences based on this new offset pairs. We also study the 128-QAM Golay complementary sequences, and propose a new de-cision condition to judge whether the sequences are 128-QAM Golay complementary.

### A Generalized Boolean Function Generator for Complementary Sequences

"... Abstract- We present a general algorithm for generating arbitrary standard complementary pairs of sequences (including binary, polyphase, M-PSK and QAM) of length ..."

Abstract
- Add to MetaCart

(Show Context)
Abstract- We present a general algorithm for generating arbitrary standard complementary pairs of sequences (including binary, polyphase, M-PSK and QAM) of length