Codebook

About: Codebook is a research topic. Over the lifetime, 8492 publications have been published within this topic receiving 115995 citations.

Code-excited linear predictive coder and decoder with conversion filter for converting stochastic and impulsive excitation signals

Abstract: A code-excited linear predictive coder or decoder for a speech signal has an adaptive codebook (105), a stochastic codebook (106), and a pulse codebook (107). A constant excitation signal (ec) is obtained by choosing between a stochastic excitation signal (es) selected from the stochastic codebook and an impulsive excitation signal (ep) selected from the pulse codebook. The constant excitation signal is filtered to produce a varied excitation signal more closely resembling the original speech signal. The varied excitation signal is combined with an adaptive excitation signal (ea) selected from the adaptive codebook to produce a final excitation signal (e) which is filtered to generate a synthesized speech signal. The final excitation signal (e) is also used to update the adaptive codebook.

Kerdock Codes for Limited Feedback Precoded MIMO Systems

Abstract: Codebook based limited feedback is a practical way to obtain partial channel state information at the transmitter in a precoded multiple-input multiple-output wireless system. In this correspondence, we propose a systematic codebook design. The proposed Kerdock codebook consists of multiple mutually unbiased unitary basis matrices with quaternary alphabet and the identity matrix. We propose to derive the beamforming and precoding codebooks from this base codebook, eliminating the requirement to store multiple codebooks. Furthermore, we show that quaternary alphabet facilitates efficient codebook storage and codeword search. We derive the chordal distance for two and four antenna codebooks, showing that the proposed codebooks compare favorably with prior designs. Monte Carlo simulations compare achievable rates and error rates for different codebooks sizes.

Embedded algebraic vector quantizers (EAVQ) with application to wideband speech coding

Abstract: A new lattice vector quantization scheme, namely embedded algebraic vector quantizers (EAVQ), is proposed. This scheme makes use of spherical subsets of the rotated Gosset lattice RE/sub 8/ to constitute a vector-quantizer codebook. The codebook consists of several sub-codebooks and has an embedded structure. The codewords can be generated using an algebraic method and do not have to be stored. In combination with transform coded excitation (TCX) coding, this quantization technique is applied to 16 kbps wideband speech coding in order to quantize the so-called target signal in the frequency domain. Compared to a stochastic complex vector quantization scheme, EAVQ can achieve better performance and lead to significant savings of memory requirements.

Precoding matrix codebook design for advanced wireless communications systems

Abstract: Methods and apparatus of constructing rank-1 and/or rank-2 codebooks for advanced communication systems with 4 transmit antennas and two-dimensional (2D) M×N transmit antenna elements are provided. A double-codebook structure is considered for 4-Tx antenna configuration. Single-codebook and double-codebook structures are considered for two-dimensional (2D) M×N transmit antenna elements.

Protocol message compression in a wireless communications system

Abstract: A method, apparatus, system, and computer software for compressing and decompressing a message for transmission. The method of compressing a text message for transmission may include parsing text strings and encoding numerical values with a binary representation and analyzing values of the text strings and populating a session specific codebook with partial strings from the values. The method of compressing a message for transmission may also include parsing the message with a template and generating at least one substring to be transmitted; parsing the at least one substring with entries in a session specific codebook and generating a first part of the compressed message; populating the session specific codebook with entries for unknown field values; parsing any unmatched substrings with entries from a first static dictionary and generating a second part of the compressed message; parsing any still unmatched substrings with entries from a second static dictionary and generating a third part of the compressed message; compressing a remainder of the substrings with a compression algorithm; and combining the first part, the second part, and the third part of the compressed message to obtain a compressed message for transmission.