In this letter, a constant-amplitude biorthogonal multicode (CABM) modulation is proposed. The proposed modulation is a biorthogonal modulation scheme that employs a constant-amplitude transmission of multicode signals by introducing a simple constant-amplitude coding scheme with redundant bits. The proposed CABM modulation can provide bandwidth efficiency up to the level (i.e., 9/16) of constant-amplitude orthogonal multicode (CAOM) modulation. We prove that our encoding scheme proposed in this letter provides this constant amplitude property. The bit-error rate (BER) performance expressions and the union bounds of the proposed CABM modulation and demodulation pairs are derived analytically. The results of the computer simulation and theoretical analysis performed show that the BER performance and the hardware complexity of the proposed CABM modulation are significantly better than those of a CAOM modulation

Recently, there has been rising concerns to provide more diverse geographic information services through the wireless Internet. However it takes too much time to transfer geographic data from server to client under the wireless Internet. It is due to the heavy geographic data and slow wireless communication speed. Also the data transmission has been restricted by mobile device capability. These lead to the limit in terms of using geographic information in the wireless environment. So it should be preceded with an effective process of reducing data size, which helps to transfer the geographic data more effectively. Macromedia's flash is real defector of vector animation with Web animation and programming capability. Flash has little data volume because it supports vector drawing techniques, and it is able to make an intuitional, dynamic, and high-quality image in real time on the Web. Besides more than 2.3 hundreds million people use it, and it is operated in the most of Web browser and computing environment. This thesis proposes a new strategy based on the dynamically generated flash using geographic data in the server side. The implementation of applicable flash shows that it considerably reduces data size and it offer fast performance and smart graphic interface on PDA.