公开(公告)号：US12108064B2

公开(公告)日：2024-10-01

申请号：US18479521

申请日：2023-10-02

Applicant: KIOXIA CORPORATION

Inventor： Daisuke Yashima ,  Masato Sumiyoshi ,  Keiri Nakanishi ,  Takashi Miura ,  Kohei Oikawa ,  Sho Kodama ,  Youhei Fukazawa ,  Zheye Wang

IPC: H04N19/423 ,  H04N19/13 ,  H04N19/146 ,  H04N19/184

CPC classification number: H04N19/423 ,  H04N19/13 ,  H04N19/146 ,  H04N19/184

Abstract: According to one embodiment, a memory system includes a frequency value update unit, a first intra-group rearranging unit, a second intra-group rearranging unit, and a routing unit. The frequency value update unit adds a first value to each of one or more first frequency values that are associated with one or more first symbols, respectively, in one or more entries in a table. The first intra-group rearranging unit rearranges first entries, which belong to a first group, using frequency values in the first entries. The second intra-group rearranging unit rearranges second entries, which belong to a second group lower than the first group, using frequency values. The routing unit rearranges at least one of the first entries and at least one of the second entries.

公开(公告)号：US12081241B2

公开(公告)日：2024-09-03

申请号：US17941345

申请日：2022-09-09

Applicant: Kioxia Corporation

Inventor： Sho Kodama ,  Masato Sumiyoshi

IPC: H03M7/40 ,  H03M7/30

CPC classification number: H03M7/405 ,  H03M7/3077 ,  H03M7/3079 ,  H03M7/4062

Abstract: According to one embodiment, a code table generation device includes a table generation unit, a merge unit and a tree generation unit. The table generation unit generates a frequency table including symbols and frequencies of occurrence respectively associated with the symbols, based on a frequency of occurrence for each symbol of input symbols. The merge unit acquires top K symbols in descending order of the frequencies of occurrence and remaining symbols from the symbols, divides the remaining symbols into one or more symbol sets, and determines a frequency of occurrence associated with a root node of each of subtrees correspond to the respective symbol sets. The tree generation unit generates a Huffman tree using the K symbols and the root node of each of the subtrees.

公开(公告)号：US11770132B2

公开(公告)日：2023-09-26

申请号：US17304130

申请日：2021-06-15

Applicant: Kioxia Corporation

Inventor： Sho Kodama ,  Masato Sumiyoshi ,  Keiri Nakanishi

IPC: H03M7/00 ,  H03M7/40 ,  G06F3/06

CPC classification number: H03M7/4093 ,  G06F3/0608 ,  G06F3/0659 ,  G06F3/0679 ,  G06F3/0655

Abstract: According to one embodiment, a compression device includes a coding information generation unit. The unit determines code lengths that are respectively associated with a plurality of symbols, based on a frequency of occurrence of each of the plurality of symbols. When the plurality of symbols include one or more first symbols that are respectively associated with one or more first code lengths exceeding an upper limit, the unit changes the first code lengths to the upper limit, selects, from one or more second symbols of the plurality of symbols that are respectively associated with one or more second code lengths shorter than the upper limit, at least one symbol in descending associated code length order, changes at least one code length associated with the symbol to the upper limit.

公开(公告)号：US11561738B2

公开(公告)日：2023-01-24

申请号：US17191845

申请日：2021-03-04

Applicant: Kioxia Corporation

Inventor： Masato Sumiyoshi ,  Keiri Nakanishi ,  Sho Kodama ,  Kohei Oikawa

IPC: H03M7/00 ,  G06F3/06 ,  H03M7/30 ,  G11C16/04 ,  H03M7/40 ,  H03M7/42

Abstract: A memory system includes a storage device and a memory controller. The memory controller includes an encoder and a decoder. The encoder includes a first code table updating section configured to update the encoding code table and an encoding flow controlling section configured to control input to the first code table updating section by using a first data amount indicating a data amount of the input symbol. The first data amount is calculated based on the input symbol. The decoder includes a second code table updating section configured to update the decoding code table and a decoding flow controlling section configured to control input to the second code table updating section by using a second data amount indicating a data amount of the output symbol. The second data amount is calculated based on the output symbol in the same way as the calculation of the first data amount.