TAILIEUCHUNG - the_handbook_of_ad_hoc_wireless_networks_5

Tham khảo tài liệu 'the_handbook_of_ad_hoc_wireless_networks_5', công nghệ thông tin, quản trị mạng phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Simpo PDF Merge and Split Unregistered Version - http perform the handover without participation of the MSC. Such handovers occur between cells that are controlled by the same BSC and are called internal handovers. They can be performed independently by the BSS the MSC is informed only about the successful execution of internal handovers. All other handovers require participation of at least one MSC or their BSSMAP and MAP parts respectively. These handovers are known as external handovers. As the MAHO scheme is similar to the GSM handover protocol the internal handover is analyzed in this chapter. The basic signaling structure for a GSM-to-MANET internal handover is presented in Fig. . In GSM-to-A-GSM handover protocol a MT requests a handover from its BSS by sending an encapsulated Handover Required message through its relay MT and starts the timer T3124 as specified in the GSM specification1 2 . The A-GSM Handover Required message Fig. contains the following elements Message type Cause handover type Cell identifier list Details of the resource that is required MT relay s The recipient MTs along the multihop path try first to see if direct communication with the BTS can be established. If so the message is sent directly to the BTS. Otherwise the Handover Required message is forwarded from each relay MT along the multihop path to the BTS. The forwarding process continues until either a relay MT found to have a direct link to BTS or a MT has neither a relay nor a direct link to BTS. In the latter case the packet is silently discarded and the handover phase resumes with failure. If failure occurs the node that reports the handover failure either sends an error message to the initiator of the handover or does not assume any action. In the former case the node that initiated the handover upon reception of the error message may initiate a new handover phase by sending a Handover Required message through a different mobile while in the latter .

• Quản trị mạng
• wireless net work
• giáo trình wireless net work
• sỏ tay wireless net work
• wireless networks
• giáo trình wireless networks