Classical random access protocols support prioritized user groups by allowing a high priority user to transmit with a relatively high probability. However, when a high priority user competes for the channel with a large number of low priority users, transmission success probability of the high priority user can still diminish to zero. In this paper, a distributed medium access control (MAC) framework is proposed to support hierarchical user groups in a random multiple access system in the following senses. First, when the number of primary users is small, the MAC framework guarantees that channel availability should stay above a pre-determined threshold no matter how many secondary users are competing for the channel. Second, when the number of primary users is large, the MAC framework drives transmission probabilities of the secondary users to zero but does not reject channel access to the primary users. These properties are achieved in a distributed environment without direct message exchange between users, without knowledge on the number of users, and without knowing whether each transmission should belong to a primary or a secondary user. The MAC framework is also extended to systems where each user can be equipped with multiple transmission options.

中文翻译：

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分级用户的随机多重访问

经典的随机接入协议通过允许高优先级用户以相对高的概率进行传输来支持优先用户组。但是，当高优先级用户与大量低优先级用户竞争信道时，高优先级用户的传输成功概率仍然可以降为零。在本文中，提出了一种分布式媒体访问控制（MAC）框架，以在以下意义上支持随机多址系统中的分层用户组。首先，当主用户数量较少时，无论有多少次用户竞争信道，MAC 框架都保证信道可用性应保持在预定阈值以上。其次，当初级用户数量较多时，MAC 框架将次要用户的传输概率驱动为零，但不拒绝对主要用户的信道访问。这些特性是在分布式环境中实现的，用户之间没有直接的消息交换，不知道用户的数量，也不知道每次传输应该属于主要用户还是次要用户。MAC 框架还扩展到每个用户都可以配备多种传输选项的系统。