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The existing cooperative spatial multiplexing (CSM) schemes for MIMO-CDMA network have four vital problems to hinder CSM's application: exact synchronization among the mobile stations(MSs) and base station (BS), spatial channels' estimation for MSs, space-time coding and decoding for BS and MSs, the implementation complexity of BS and MSs. To solve the problems, a simplified cooperative spatial multiplexing...
The existing encodable irregular LDPC codes may have a degraded BER performance when it is derived from classical regular QC LDPC codes since both girth property and weight property are not carefully given attention to two or more thing, which lead to some codes with large girths have small minimum weights and poor BER performance. To solve the problem, we propose a new approach to construct the encodable...
This paper reveals that the current LDPC codes in DVB-S2 are not good, since they have the codes of minimum weight of 5, which leads to their BER can not satisfy the requirements of DVB-S2. This paper develops an algorithm to estimate the minimum weight of LDPC codes based on generator matrices. Using it, we can find the minimum weight problem of the current LDPC codes in DVB-S2. To enhance the minimum...
To combine presented MIMO scheme with multiuser detectors for uplink will suffer from the problems of high computation complexity and channel coherency. So, in this paper we propose a MIMO multiuser detection (MUD) scheme that reduces considerably the system computation complexity. The proposed algorithm adopts inverse channel matrix for MIMO decoding, which is not sensitive to the coherency of channels...
Because of the independency of the MIMO Rayleigh channels, the capacity of a MIMO CDMA network is often limited by co-channel interference. In the uplink, sophisticated multiuser detection (MUD) can be implemented at the base stations (BS) to counter the co-channel interference. However, on the downlink, the receivers at the mobile stations (MS) are usually required to be simple, therefore complex...
The presented LDPC-codec has no encrypting function since its rediscovering, and the presented encrypting for signal transmission needs additional algorithm and program, which leads the great time delay for the signal receiving. This paper reveals that LDPC-codec itself can have the desired encrypting faction if adopting our processing approach for the generator matrices of transmitters and parity...
Presented low-density parity-check (LDPC) decoding exhibits poor BER performance for multipath channel (MPC). To solve the problem, this paper proposes an adaptive LDPC decoding system, which composes two parts: adaptive equalizer and LDPC decoder. In this scheme, adaptive equalizer resorts to the training sequence transmitted from transmitter, removes the multipath interference (MPI), then LDPC decoder...
The BER performance of presented quasi-cyclic (QC) low-density parity-check (LDPC) codes is not good as that of randomly constructed LDPC codes, while the lack of structure of randomly constructed LDPC codes implies serious disadvantages in terms of storing and accessing a large parity-check matrix. To solve the problems, this paper proposes a design of good quasi-cyclic (QC) low-density parity-check...
Turbo-code has been applied in many fields except for the field of secret communication since its appearance. This paper presents a method on designing soft encrypting wireless channel based on turbo-code. The method utilizes existing wireless transmitting channel to realize secret communication based on turbo-code en-decoders. This paper also presents the encrypting method, which has the compositive...
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