• The role of spectrum manager in IEEE 802.22 standard

      Afzal, Humaira; Mufti, Muhammad R.; Nadeem, M.; Awan, Irfan U.; Khan, U.S. (2014)
      The IEEE 802.22 is the first worldwide standard for wireless regional area network (WRAN) based on cognitive radio techniques. It provides access to use unused TV band without causing any harmful interference to the incumbents. This paper aims to elaborate the significance of the Spectrum Manager (SM) in WRAN Base Station (BS). It is responsible to maintain spectrum availability information of the cell. Using incumbent database, geolocation and spectrum sensing results, the SM defines the status of the channels with respect to incumbent detection. On the basis of channel status, the SM classifies the channel into different categories. A pseudocode has been proposed for the SM to perform channel decision process in two steps. Spectrum etiquette procedure is activated due to incumbent detection, neighboring WRAN cell detection/update, operating channel switching request and contention request obtained from neighboring WRAN cells. An example is given to demonstrate this procedure in a WRAN cells. Spectrum handoff mechanisms is initiated through the SM either when primary user is detected on the licensed channel or when the specified transmission time is terminated as discussed in the IEEE 802.22 standard. Other responsibilities of the SM are to impose IEEE 802.22 policies within the cell to ensure incumbent protection and maintain QoS in WRAN system. The policies are concerned with events and their corresponding actions. The SM also controls the sensing behavior of the Spectrum Sensing Automation (SSA), where SSA is an entity that must be present in all IEEE 802.22 devices which performs spectrum sensing through spectrum sensing function (SSF) after receiving request from SM.