This chapter contains sections titled: Introduction Overview of Multicarrier CDMA Systems Channel Model Performance of MC-CDMA System Performance of Overlapping Multicarrier DS-CDMA Systems Performance of Multicarrier DS-CDMA-I Systems Performance of AMC DS-CDMA Systems Performance of SFH/MC DS-CDMA Systems Chapter Summary and Conclusion 
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Overview of Multicarrier CDMA

A base station does not transmit any reference signal (RS) for channel measurement in a subframe in which transmission of an RS collides with transmission of a synchronization signal or a broadcast signal or in a resource block including the synchronization signal or the broadcast signal in the subframe. A user equipment assumes that any RS for channel measurement is not transmitted in a subframe or in a resource block when transmission of an RS collides with transmission of a synchronization signal or a broadcast signal in the subframe or in the resource block.

Method and base station for receiving reference signal, and method and user equipment for receiving reference signal

This user terminal is characterized by having: a transmission unit that uses an uplink control channel resource in a prescribed bandwidth part (BWP) and sends uplink control information; and a control unit that determines the correspondence between said uplink control channel resource and a prescribed index, on the basis of prescribed information, and specifies the uplink control channel resource. As a result of the present invention, reduction in communication throughput can be suppressed even when performing control on the basis of BWP.

User terminal and wireless communication method

This paper proposes broadband packet wireless access employing Variable Spreading Factor-Orthogonal Frequency and Code Division Multiplexing (VSF-OFCDM) with two-dimensional spreading that prioritizes time domain spreading in the forward link and multi-carrier/DS-CDMA (MC/DS-CDMA) in the reverse link for the system beyond IMT-2000. Based on the wireless access scheme, we propose major radio air interfaces in the physical layer to achieve our target maximum throughput beyond 100 Mbps and 20 Mbps in the forward and reverse links, respectively. Furthermore, we present key technologies such as the adaptive radio link parameter control coupled with link adaptation, pilot channel assisted coherent detection in both links, adaptive antenna array beam forming transmitter and receiver, cell search, and channel coding. Finally, simulation results elucidate that VSF-OFCDM using die proposed radio link parameters achieves a throughput above 100 Mbps at the average received signal energy per symbol-to-background noise power spectrum density ratio (Ea/No) of approximately 13 dB (101.5 MHz bandwidth, without antenna diversity reception, 12-path Rayleigh fading channel). Furthermore, MC/DS-CDMA realizes a throughput above 20 Mbps at the average received Ea/No of approximately 8 dB (40 MHz bandwidth, with antenna diversity reception, 6-path Rayleigh fading channel).

Broadband packet wireless access based on VSF-OFDM and MC/DS-CDMA

Frequency-domain equalization (FDE) based on minimum mean square error (MMSE) criterion can replace the conventional rake combining with significantly improved bit error rate (BER) performance for the downlink DS-CDMA in a frequency-selective fading channel. Recently, a new MMSE-FDE technique that requires no GI insertion has been proposed to avoid inter-block interference (IBI) (this technique is called overlap FDE). However, the residual IBI is produced and degrades the BER performance. Furthermore, the presence of an inter-chip interference (ICI) after MMSE-FDE limits the BER performance improvement. In this paper, we propose an iterative overlap FDE for DS-CDMA downlink to suppress both IBI and ICI. In the iterative overlap FDE, joint MMSE-FDE and ICI cancellation is repeated a sufficient number of times and the middle part of M chips is picked up. The BER performance with the iterative overlap FDE is evaluated by computer simulation.

http://www.mobile.ecei.tohoku.ac.jp/paper/pdf/inter_2006/14_in_2006_takeda.pdf

Iterative Overlap FDE for DS-CDMA without GI

Parameter Optimization for Adaptive Control CRE in HetNet

Disclosed is to properly perform communications even in an environment enabled to use different TTI lengths in combination. User equipment in one aspect of the present invention includes: a control unit that specifies a configuration of a plurality of transmission time intervals (TTI: Transmission Time Interval) contained in one subframe of an existing system; and a reception unit that receives downlink control information at a radio resource receiving allocation of PDCCH (Physical Downlink Control Channel) of the existing system or at a first TTI of the plural TTIs, and receives data at, at least, one of the plural TTIs on the basis of the downlink control information.

User equipment, wireless base station, wireless communication method, and wireless communication system

In a wireless communication system comprising a base station and a user equipment, the user equipment, which communicates with the base station, is provided with: a storage unit which stores association information that associates identifiers of beams formed by the base station and configuration information for use in transmission of a random access signal; a selection unit which selects a specific beam on the basis of reception quality of a signal transmitted from the base station by multiple different beams, and which, on the basis of the association information, selects configuration information corresponding to said specific beam; and a transmission unit which uses the configuration information selected by the selection unit to transmit a random access signal to the base station.

User equipment and random access method

The purpose of the present invention is to improve the performance of an uplink control channel to be code-division-multiplexed among multiple user devices. The user device has: a transmission unit for transmitting an uplink control channel, including data to which an orthogonal cover code is applied prior to discrete Fourier transform and a demodulation reference signal to which a cyclic shift is applied; and a control unit for performing control for the determination of the cyclic shift on the basis of an index of the orthogonal cover code, a time resource for the demodulation reference signal, and the length of the orthogonal cover code or the maximum value of the length.

User device and radio communication method

PROBLEM TO BE SOLVED: To provide a mobile terminal device, a radio communication method, and a radio communication system capable of efficiently transmitting feedback information on a physical uplink control channel.SOLUTION: The mobile terminal device of the present invention is a mobile terminal device for transmitting a plurality of ACK/NACK control information and reference signals by using a physical uplink control channel format configured from a plurality of time blocks, said terminal device comprising: cyclic shift imparting means for imparting a cyclic shift to a plurality of reference signal blocks among the plurality of time blocks; and orthogonal code multiplication means for multiplying the plurality of reference signal blocks by an orthogonal code. The cyclic shift imparting means imparts, to the plurality of reference signal blocks, a cyclic shift determined on the basis of the orthogonal code by which the plurality of ACK/NACK control information blocks among the plurality of time blocks are multiplied.

Takeda Kazuaki

Papers

Parameter Optimization for Adaptive Control CRE in HetNet

User equipment, wireless base station, wireless communication method, and wireless communication system

User equipment and random access method

User device and radio communication method

Mobile terminal device, radio communication method, and radio communication system