2015/5/15(五) 14:20 - 李穎 教授 (元智大學通訊系) - In Search of Orthogonality: From Barker to Golay Complementary Sequences
Topic：In Search of Orthogonality: From Barker to Golay Complementary Sequences
Date&Time：2015/5/15(五) 14:20
Speaker：李穎 教授 (元智大學通訊系)
Location：清華大學台達館 R216
Abstract：
Moving correlation is an operation used in communications to “find” a signal. If a signal is orthogonal to its shifted versions, it can be found with high precision, and can also provide information such as the system’s impulse response. In digital communications, such a signal corresponds to a sequence with an impulse(-like) auto-correlation function. The construction of such sequences—with small alphabets and variable lengths—has proved to be very challenging and sometimes impossible. One way to alleviate this difficulty is to construct sequence pairs that are “shift orthogonal” in a pairwise sense instead. In this talk, background on Golay complementary sequence pairs is introduced and some recent results are presented. Golay complementary sequences have been employed in WLAN(IEEE 802.11b/g), WiMAX(IEEE 802.16) and WPAN(IEEE802.15.3c). It is now known that Golay complementary sequences with small alphabets exist for all sequence lengths. Extension to multi-dimensional Golay complementary array pairs is also discussed.
Date&Time：2015/5/15(五) 14:20
Speaker：李穎 教授 (元智大學通訊系)
Location：清華大學台達館 R216
Abstract：
Moving correlation is an operation used in communications to “find” a signal. If a signal is orthogonal to its shifted versions, it can be found with high precision, and can also provide information such as the system’s impulse response. In digital communications, such a signal corresponds to a sequence with an impulse(-like) auto-correlation function. The construction of such sequences—with small alphabets and variable lengths—has proved to be very challenging and sometimes impossible. One way to alleviate this difficulty is to construct sequence pairs that are “shift orthogonal” in a pairwise sense instead. In this talk, background on Golay complementary sequence pairs is introduced and some recent results are presented. Golay complementary sequences have been employed in WLAN(IEEE 802.11b/g), WiMAX(IEEE 802.16) and WPAN(IEEE802.15.3c). It is now known that Golay complementary sequences with small alphabets exist for all sequence lengths. Extension to multi-dimensional Golay complementary array pairs is also discussed.