The collision channel without feedback (CCw/oFB) introduced by Massey and Mathys, depicts a scenario where multiple users share a communication channel but have arbitrary time offsets, and can never learn these time offsets due to the lack of feedback. This paper considers an extension of the CCw/oFB, which allows the receiver to use successive interference cancellation (SIC) to cancel the interference caused by those collided packets whose contents have been known by the receiver. We derive the zero-packet-loss throughput regions of this model for both the unsynchronized and slot-synchronized cases. Given an arbitrary number of users and a packet alphabet of arbitrary size, it is shown that these two regions coincide, and the outer boundary of this common region is the set of all points with only nonnegative components that add up to one. It is further shown that all points on this outer boundary with only rational components can be achieved without packet loss in the slot-synchronized case. The constructive proofs are based on a joint design of protocol sequences, identification/location algorithm and erasure correcting codes. These findings indicate that the negative impact of the lack of time synchronization on the throughput performance can be removed by the help of SIC.

中文翻译：

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在没有反馈和任意时间偏移的情况下实现冲突通道的零丢包吞吐量1


Massey和Mathys提出的无反馈碰撞信道（CCw/oFB）描述了多个用户共享通信信道但具有任意时间偏移的场景，并且由于缺乏反馈而永远无法学习这些时间偏移。本文考虑CCw/oFB的扩展，它允许接收器使用连续干扰消除（SIC）来消除那些接收器已知其内容的冲突数据包所造成的干扰。我们针对非同步和时隙同步情况得出了该模型的零丢包吞吐量区域。给定任意数量的用户和任意大小的数据包字母表，表明这两个区域重合，并且该公共区域的外边界是仅具有加起来为 1 的非负分量的所有点的集合。进一步表明，在时隙同步情况下，仅用有理分量即可实现该外边界上的所有点，而不会丢失数据包。构造性证明基于协议序列、识别/定位算法和纠删码的联合设计。这些发现表明，缺乏时间同步对吞吐量性能的负面影响可以通过 SIC 的帮助消除。