The customized macro base station(MBS) adopting low frequency like 800MHz for wide coverage has become a key product for operators to re-farming and fill the blind in rural and suburb scenarios. However, in real network, the frequency resources of customized MBS are configured statically, while some MBSs adopts dynamic spectrum sharing(DSS) to optimize frequency. Therefore, inter-symbol interference(ISI) between LTE cell-specific reference signal(CRS) and NR synchronization signal/ physical broadcast channels (PBCH) block (SSB) signal in co-frequency is introduced in hybrid outdoor networking with LTE and NR coexistence. To solve ISI coordinately and consider resource allocation, we introduce rate split multiple access(RSMA) and propose a LTE and NR ISI optimization scheme based on OFDMA-RSMA jointly MBSs grouping and power allocation in DSS and static MBSs hybrid network to maximize the overall system throughput. We convert 4G/5G signal to common/private message to segment and separate the signal via RSMA. Then we decode all selected MBSs and combine common message in co-frequency to eliminate the interference and enhance the quality of service(QoS) via multiple MBSs collaboration networking. To choose the suitable MBSs for servicing the user, MBSs grouping algorithm based on SINR optimization is adopted and gradient descent is used to solve this convex issue to allocate power according to types of frequency and message. Simulation results show better system throughput performance and reduced ISI compared with the other three baseline algorithms.

The coexistence of NR and LTE in the same frequency is a promising technology to ensure a smooth migration path for the frequency reframing from LTE to NR. However, field trial results have shown the inter-cell interference caused by cell reference signal from surrounding LTE cells reduce the 5G system performance severely. The traditional CRS-IC based interference mitigation algorithms greatly increase the design complexity of UE receiver structures and have not been widely used in commercial network. In view of this fact, this paper proposes a novel low-complexity interference mitigation algorithm for NR system to reduce the co-channel interference from LTE cell. The performance of the proposed scheme is compared to the zero-power rate matching-based scheme by means of link level simulations that follow the 3GPP guidelines. The simulation results show that the proposed scheme can provide significant gains.

The model of memoryless Gaussian channel with deterministic interference are common in various engineering applications. In this letter we propose a non-data-aided algorithm for joint measurement of the interference level and the noise power. The algorithm applies an iterative approach based on the maximum likelihood criterion. The Cramer-Rao bound (CRB) is also derived as the performance benchmark. Simulation results show that the proposed approach has fast convergence speed and its measurement performance is almost identical to the CRB.

Based on the minimum mean-square error (MMSE) criterion, a new blind multiuser detector is proposed. The searching space for the optimal detector is constrained according to the spreading code and channel properties of the desired user. The proposed constraint technique can guarantee that the optimal detector associated with the desired user locates in the searching space, whereas the existing methods consider only the spreading code and, consequently, cannot guarantee that the target optimal detector locates in the constrained searching space. Theoretical analysis and numerical results are presented.