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Methods and apparatus for partial interference reduction within wireless networks

專利號(hào)
US10785783B2
公開(kāi)日期
2020-09-22
申請(qǐng)人
APPLE INC.(US CA Cupertino)
發(fā)明人
Markus Mueck; Maik Bienas; Andreas Schmidt
IPC分類
H04K1/10; H04L27/28; H04W72/12; H04J11/00; H04L5/00; H04L25/497; H04B15/00; H04W72/08
技術(shù)領(lǐng)域
bs,ue,pilot,tones,in,data,cir,or,be,frequency
地域: CA CA Cupertino

摘要

Methods and apparatus that enable one or more wireless networks to minimize inter-cellular interference (ICI) at a receiver. In one embodiment, the network comprises an OFDM-based cellular network, and the method comprises utilizing a priori knowledge of non-data portions of signals from multiple base stations in order to schedule transmissions. In one variant, these non-data portions comprise pilot tones; the pilot tones can be scheduled onto various time-frequency resources of the network so as to minimize ICI. The mobility context of the receiver can also be used as a basis for dynamically adjusting the pilot tone density. In another variant, precoding (e.g., Tomlinson-Harashima precoding) can be applied to “shape” the non-data portions of the transmitted signals so as to mitigate ICI. In yet other variants, frame preambles and learning sequences are used as the basis for invoking selective transmission time shifts across the potentially interfering base stations so as to minimize ICI.

說(shuō)明書

In the present context, various definitions of a “neighboring cell” can be applied, depending on the particular network implementation (including e.g., the level of communications between cells, level of extant processing overhead, density of base stations, etc.). In one embodiment, a cell served by a BS #1 is considered to be a neighboring cell of cell (BS) #2 if: i) the transmission bands overlap at least partly between the BSs of cells #1 and #2; and ii) the maximum transmitted power spectral density from BS #1 perceived in cell #2 (i.e., typically the transmitted power spectral density of the BS in cell #1 combined with the propagation path loss which the signal undergoes prior to arriving in cell #2) is above a defined threshold. This threshold depends on the transmission parameters of the BS in cell #2, including for example the channel coding scheme, the signal constellation type (BPSK, QPSK, QAM16, QAM64, QAM256, etc.), the target Packet Error Rate (PER), etc. This threshold may be statically employed (i.e., does not change with time or operating conditions), or alternatively may be dynamically varied as a function of one or more of the foregoing parameters. For instance, if the target PER/BER increases, then more cells might be considered “neighbors” so as to account for or mitigate their interference effects. In one variant, a specific “threshold value” in the range from approx. 0 dB (assuming strong turbo coding or LDPC (low density parity check) coding, and very robust constellations such as BPSK) to approx. 45 dB (assuming channel coding and sensitive constellation types such as QAM256) is utilized, although it will be recognized that other values and ranges may be applied. Hence, with the foregoing definition, any cell that potentially impacts the decoding of the useful signal of a given cell is considered to be a “neighboring” of that latter cell.

權(quán)利要求

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