摘要:
In a cable television (CATV) data communication network, channel throughput and communications robustness are increased in a manner that improves speed of data transmission while maintaining compatibility with existing specifications and equipment. Enhanced throughput can be realized using the return channel of the CATV network. Alternatively, data retransmission and/or diversity techniques can be used to improve throughput.
摘要:
A single transducer digital communication receiver is described which is capable of extracting the data bits of at least one desired signal in the presence of interfering signals of similar type. The present invention also seeks to provide a communication system in which overlapping transmissions are tolerated and allowed. The present invention describes a design for a digital communication system, according to a specific frequency plan, which includes an appropriate digital demodulator that extracts the data bits of the desired signal(s) in the presence of closely spaced signals. The present invention enables reduced channel spacing in digital communication systems and thereby increases the system capacity (i.e. the number of users per bandwidth unit) without incurring any significant loss in system performance (e.g. power margins, BER, and channel availability). It also allows a reduced power margin that is required to maintain a pre-specified performance level without sacrificing system capacity. These two factors, power margin and system capacity, play a central role in the design and construction of state-of-the-art digital communication systems which seek to pack more users on the same frequency band without incurring significant power loss. Thus, the present invention also provides a method and apparatus for upgrading existing systems such as a cellular system for mobile wireless communications that is based on the IS-54 or the GSM standard.
摘要:
A method and apparatus for controlling an equalizer receiving the output of an unknown system in order to produce a desired response for recovering the input to the system are characterized by iteratively adjusting the equalizer such that the unknown system combined with the equalizer behaves essentially as a linear system whose (t,n) taps, for some combinations of t and n, are iteratively adjusted according to the following rule: ##EQU1## where s.sub.t,n denotes the (t,n) tap before the iteration, s'.sub.t,n denotes the (t,n) tap after the iteration, I is a preselected integer greater then or equal to one, .alpha..sub.i i=1,2 . . . I are preselected scalars that may vary from iteration to iteration, and p.sub.i, q.sub.i i=1,2, . . . I are preselected non-negative integers such that p.sub.i +q.sub.i .gtoreq.2.
摘要:
A method for data storage in a memory that includes a plurality of analog memory cells includes estimating respective achievable storage capacities of the analog memory cells. The memory cells are assigned respective storage configurations defining quantities of data to be stored in the memory cells based on the estimated achievable capacities. The data is stored in the memory cells in accordance with the respective assigned storage configurations. The achievable storage capacities of the analog memory cells are re-estimated after the memory has been installed in a host system and used for storing the data in the host system. The storage configurations are modified responsively to the re-estimated achievable capacities.
摘要:
A method for data storage includes storing data in a memory that includes one or more memory units, each memory unit including memory blocks. The stored data is compacted by copying at least a portion of the data from a first memory block to a second memory block, and subsequently erasing the first memory block. Upon detecting a failure in the second memory block after copying the portion of the data and before erasure of the first memory block, the portion of the data is recovered by reading the portion from the first memory block.
摘要:
A method for data storage in a memory that includes multiple analog memory cells fabricated using respective physical media, includes identifying a group of the memory cells whose physical media have deteriorated over time below a given storage quality level. A rejuvenation process, which causes the physical media of the memory cells in the group to meet the given storage quality level, is applied to the identified group. Data is stored in the rejuvenated group of the memory cells.
摘要:
A method for data storage includes, in a memory that includes at least N memory units, each memory unit including memory blocks, defining superblocks, each superblock including a respective set of N of the memory blocks that are allocated respectively in N different ones of the memory units, such that compaction of all the memory blocks in a given superblock is performed without any intervening programming operation in the given superblock. Data is stored in the memory by computing redundancy information for a selected portion of the data, and storing the selected portion and the redundancy information in the N memory blocks of a selected superblock.
摘要:
A method for data storage includes, in a memory that includes multiple memory blocks, specifying at a first time a first over-provisioning overhead, and storing data in the memory while retaining in the memory blocks memory areas, which do not hold valid data and whose aggregated size is at least commensurate with the specified first over-provisioning overhead. Portions of the data from one or more previously-programmed memory blocks containing one or more of the retained memory areas are compacted. At a second time subsequent to the first time, a second over-provisioning overhead, different from the first over-provisioning overhead, is specified, and data storage and data portion compaction is continued while complying with the second over-provisioning overhead.
摘要:
A method for data storage includes initially storing a sequence of data pages in a memory that includes multiple memory arrays, such that successive data pages in the sequence are stored in alternation in a first number of the memory arrays. The initially-stored data pages are rearranged in the memory so as to store the successive data pages in the sequence in a second number of the memory arrays, which is less than the first number. The rearranged data pages are read from the second number of the memory arrays.
摘要:
A method for data storage includes storing data, which is encoded with an Error Correction Code (ECC), in a group of analog memory cells by writing respective first storage values to the memory cells in the group. After storing the data, respective second storage values are read from the memory cells in the group, and the read second storage values are processed so as to decode the ECC. Responsively to a failure in decoding the ECC, one or more of the second storage values that potentially caused the failure are identified as suspect storage values. Respective third storage values are re-read from a subset of the memory cells that includes the memory cells holding the suspect storage values. The ECC is re-decoded using the third storage values so as to reconstruct the stored data.