NTT DoCoMo

About: NTT DoCoMo is a based out in . It is known for research contribution in the topics: Base station & Mobile station. The organization has 4032 authors who have published 8655 publications receiving 160533 citations.

Method for interference-minimizing resource block-size selection at a macrocell, a microcell and a femtocell

Abstract: A method for minimizing interference is applicable to a primary network whether or not spectrum resources are assigned to its users using a block-wise subcarrier assignment scheme or a randomized allocation scheme. The identified unused spectrum resources that are to be assigned to the users of the opportunistic network exclude un-used subcarriers adjacent to subcarriers used by the users of the primary network to avoid interference. The opportunistic network may assign the identified unused spectrum resources using a scheme that selects a block size for an adaptive modulation and coding scheme or for avoidance of waste of spectrum resources.

Link-Level Performance of Downlink NOMA with SIC Receiver Considering Error Vector Magnitude

Abstract: This paper presents the link-level performance of downlink non-orthogonal multiple access (NOMA) with successive interference cancellation (SIC) receiver, considering the influence of error vector magnitude (EVM) In our evaluations, for the case of a 1-by-2 transmission and the number of NOMA multiplexed users is two, we clarify the performance of NOMA for cell-center user equipment (UE) with codeword level SIC (CWIC) receiver and the performance of the cell-edge UE, which does not apply SIC Based on link-level performance evaluations, we show that the performance of CWIC receiver is almost the same as that of ideal SIC when the allocated transmit power ratio to cell-center UE is less than 035, the modulation and coding scheme (MCS) of cell-center UE is 16QAM (R = 051) or 64QAM (R = 047), and the MCS of cell-edge UE is QPSK (R = 051) Furthermore, we also show that, when EVM value is 4 % and the allocated power ratio to cell-center UE is between 02 and 037, the level of degradation due to the influence of EVM is below 06 dB, which is almost the same level of degradation as that of orthogonal frequency division multiple access (OFDMA) for the EVM value required by 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) On the other hand, we show that the influence of EVM is marginal for cell-edge UE compared to cell-center UE However, when the cell-center UE uses a higher order modulation such as 64QAM, we show that the required SNR of cell-edge UE increases due to the increase in inter-user interference Based on these results, we clarify that it is important for the base station (BS) to take into account the target BLER and influence of EVM when selecting the MCS and allocated transmit power ratio of NOMA UEs

Wavelet based multiresolution video representation with spatially scalable motion vectors

Abstract: Wavelet based multiresolution video representations generated by multi-scale motion compensated temporal filtering (MCTF) and spatial wavelet transform are disclosed. Since temporal filtering and spatial filtering are separated in generating such representations, there are many different ways to intertwine single-level MCTF and single-level spatial filtering, resulting in many different video representation schemes with spatially scalable motion vectors for the support of different combination of spatial scalability and temporal scalability. The problem of design of such a video representation scheme to full the spatial/temporal scalability requirements is studied. Signaling of the scheme to the decoder is also investigated. Since MCTF is performed subband by subband, motion vectors are available for reconstructing video sequences of any possible reduced spatial resolution, restricted by the dyadic decomposition pattern and the maximal spatial decomposition level. It is thus clear that the family of decomposition schemes provides efficient and versatile multiresolution video representations for fully scalable video coding.

Transmission apparatus, reception apparatus, mobile communications system and transmission control method

Abstract: A disclosed transmission apparatus comprises a switching portion that switches radio access methods; a frequency domain signal generation portion that allocates a radio resource to a spread chip sequence on which one of a fast Fourier transformation and a series/parallel conversion is performed in accordance with the switched radio accessed method, so as to generate a signal in a frequency domain; and a transmission signal generation portion that performs a fast inverse Fourier transformation on the signal in the frequency domain so as to generate a transmission signal.