What are the relationships between the conference rate and participant rate

WLAN rate refers to the wireless rate of data transmissions between APs and STAs or between bridges and downstream nodes. Devices on both ends work in half-duplex mode, that is, they can only receive or send data at a time. The WLAN rate is the sum of upstream and downstream rates. Common users mainly use Internet access services to browse web pages, most of which is downstream traffic. In this case, the WLAN rate refers to the downstream rate.

1. The WLAN physical rate is the physical layer rate of a radio interface, that is, the physical layer rate at which a radio interface keeps sending data. For example, the 802.11b physical rate is 11 Mbit/s and the 802.11g physical rate is 54 Mbit/s. 2. What is the relationship between the user theoretical rate and physical rate? The physical rate indicates only the performance of a radio interface, but users only care about how much bandwidth and rate they can use. The following uses the 802.11b standard as an example and assumes that a user packet is 1500 bytes. After a 32-byte header is prepended to the packet, the packet is longer than an Ethernet data frame. The checksum bits in 802.11b and Ethernet are both 4 bytes. The longest data frames (1536 bytes) are transmitted at the rate of 11 Mbit/s. The transmission time is [1536 (bytes) x 8 (bit)]/11 Mbit/s = 1117 microseconds. On the WLAN, a link code and PLCP header (exclusively used by WLAN) are prepended to a data frame. The transmission time of the link code and PLCP header is 192 microseconds. In addition to the interframe gap, a random period (delay offset) is required during the transmission of data frames on WLANs. In 802.11b, the average delay offset is 360 microseconds. On the WLAN, an ACK frame is received from the remote end each time a data frame is sent to confirm successful communication. The next data frame is sent only after the ACK frame is received. The total transmission time is 213 microseconds. The transmission time of a 1500-byte data frame includes the waiting time and ACK transmission time, equaling 1882 microseconds. 1117 + 192 + 360 + 213 = 1882 In this case, the theoretical maximum UDP throughput for 1500-byte data frames is 7.1 Mbit/s. 3. The preceding calculation result is based on the UDP model and 1500-byte frames. The actual usage scenarios are much complex than the preceding scenario. Additionally, the number of STAs also greatly affects AP performance. Therefore, the actual user rate is usually tested. In most cases, the actual rate of 802.11b can reach about 4.7 Mbit/s.

The impacts are as follows: - If the bandwidth, format, or protocol of each participant is inconsistent, rate adaptation resources of the MCU will be occupied. Under this situation, the rate adaptation function must be enabled when conferences are scheduled on the RM; otherwise, conferences cannot be held. When rate adaptation resources are sufficient, conferences can be properly held. If rate adaptation resources are insufficient, the system displays a message indicating that conferences cannot be held because of insufficient rate adaptation resources. - Generally, it is recommended that you set the same format, protocol, and rate for all participants on the RM to save rate adaptation resources. The rate of an E1 line participant is 1920 kbit/s.

When a conference is initiated on the MCU, the network bandwidth occupied by the MCU is the sum of network bandwidth occupied by all participants. For example, if 10 participants join a 2 Mbit/s conference, the network bandwidth occupied by the MCU is 20 Mbit/s (2 x 10).