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Chapter 7 – Aloha-Based Protocol
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Table 7.1 RFID standards and products
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Figure 7.1 Reader and tags interactions
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Figure 7.2 Pure Aloha with muting
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Figure 7.3 Pure Aloha with slow down
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Figure 7.4 Pure Aloha with fast mode
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Figure 7.5 Slotted Aloha with early end
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Figure 7.6 λ = 20, K = 5 λ is the offered load and K is the maximum retransmission delay Klair et al. 2009
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Figure 7.7 Number of collision to read n tags
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Figure 7.8 Number of idle slots encountered when reading n tags
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Table 7.2 Optimal frame sizes for a given tag range
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Figure 7.9 (a) A CD frame precedes each jump frame.
The number of slots in each jump frame corresponds to the number of successful transmissions in the CD frame; in this example, only two tags successfully transmitted their ID. Tags that transmitted successfully in the CD frame then send their full ID in the jump frame.
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Figure 7.9 (b) Collision detection using Manchester encoding
no transition in the middle of a bit indicates a collision
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Table 7.3 EDFSA frame sizes
n denotes the number of tags, N is the frame size, and M is the number of tag groups.
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Figure 7.10 ResMon Frames
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Figure 7.11 An example showing QT being used to identify the following tags: A (0111), B (0000), C (0101) and D (0001). In scenario (ii), only tags A and B contend with each other. Tag C and D will contend at a different time.
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Figure 7.12 Reading delay of BFSA, DFSA, and EDFSA variants
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Figure 7.13 Average number of collisions encountered when reading n tags
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Figure 7.14 Average number of idle slots encountered when reading n tags
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