1.2 RFID System Anti-Collision Technology
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Fig. 1.1 The comparison of the four channel capacities
Compared with SISO, SIMO, and MISO systems, the channel capacity of the
MIMO system increases linearly, and the channel capacity of the four systems and
SNR ξ is logarithmic. Therefore, it is possible and effective to increase the data
transmission rate and channel capacity by increasing the number of transmitting
antennas and receiving tags.
MIMO (4 × 4) and SISO (1 × 1), SIMO (1X4), and MISO (4 × 1) channels
were selected for simulation, with the minimum SNR min = 0dB and maximum
SNR max = 45dB. Figure 1.1 shows the relationship between channel capacity and
SNR of SISO, SIMO, MISO, and MIMO channels.
As can be seen from Fig. 1.1, the channel capacity of SIMO (1 × 4) and MISO
(4 × 1) systems is basically the same; Under the same signal-to-noise ratio, the
channel capacity of MIMO (4 × 4) system is significantly higher than that of SIMO
(1 × 4) and MISO (4 × 1) system. The channel capacity of SIMO (1 × 4) and
MSO(4 × systems is increased compared to that of SISO systems.
The MIMO channel capacity of different tag combinations was analyzed when N
= M, and the 2 × 2, 4 × 4, 6 × 6, and 8 × 8 multi-tag and multi-antenna systems were
selected to establish the simulation model. Figure 1.2 shows the relationship curve
between the channel capacity of different tag combinations and SNR. At this point,
the channel capacity increases logarithmically with the number of readers and tags.
In other words, the channel capacity can be increased exponentially by increasing
the number of antennas at the sending end and tags at the receiving end.
13
Fig. 1.1 The comparison of the four channel capacities
Compared with SISO, SIMO, and MISO systems, the channel capacity of the
MIMO system increases linearly, and the channel capacity of the four systems and
SNR ξ is logarithmic. Therefore, it is possible and effective to increase the data
transmission rate and channel capacity by increasing the number of transmitting
antennas and receiving tags.
MIMO (4 × 4) and SISO (1 × 1), SIMO (1X4), and MISO (4 × 1) channels
were selected for simulation, with the minimum SNR min = 0dB and maximum
SNR max = 45dB. Figure 1.1 shows the relationship between channel capacity and
SNR of SISO, SIMO, MISO, and MIMO channels.
As can be seen from Fig. 1.1, the channel capacity of SIMO (1 × 4) and MISO
(4 × 1) systems is basically the same; Under the same signal-to-noise ratio, the
channel capacity of MIMO (4 × 4) system is significantly higher than that of SIMO
(1 × 4) and MISO (4 × 1) system. The channel capacity of SIMO (1 × 4) and
MSO(4 × systems is increased compared to that of SISO systems.
The MIMO channel capacity of different tag combinations was analyzed when N
= M, and the 2 × 2, 4 × 4, 6 × 6, and 8 × 8 multi-tag and multi-antenna systems were
selected to establish the simulation model. Figure 1.2 shows the relationship curve
between the channel capacity of different tag combinations and SNR. At this point,
the channel capacity increases logarithmically with the number of readers and tags.
In other words, the channel capacity can be increased exponentially by increasing
the number of antennas at the sending end and tags at the receiving end.