Field Octet Bits Values [0] Line coding 0:8B10B, 1:HCM 0:2-PAM 1:4-PAM [3:1] Modulation 2:8-PAM 3:16-PAM Stream 1 3 >3: reserved 0: NHCM=0 1: NHCM=1 [7:4] NHCM … 15: NHCM=15 Stream 2-4 4-6 [31:8] … … Table 4: Descriptor for the MCS vector. IRS type defines the use of time- or frequency-domain IRS. Time-domain IRSs typically apply for transmission without FDE at lower optical clock rates. They are also sufficient for stream transmission. Frequency-domain IRSs enable transmission at higher optical clock rates using FDE and orthogonal transmission and detection of IRSs for multiple streams. If FT=1 (probe frame), optional fields provide a time reference, descriptors for explicit reference sequences (ERS) and the ERS themselves. ERS enable measurement of the direct channel matrix from individual transmitters to individual receivers. The most important role of a probe frame is the beacon sent at the beginning of a superframe. Field Octet Bits Description Start of probe frame, Time_stamp 3-6 [31:0] 10 time resolution ERS_type 7 [7:0] Type of ERS NERS 8 [7:0] Number of ERS ERS n. a. n. a. Block of ERS Table 5 Optional fields for FT=1.
Field Octet Bits Values Stream 1 3 [0] Line coding 0:8B10B, 1:HCM [3:1] Modulation 0:2-PAM 1:4-PAM 2:8-PAM 3:16-PAM >3: reserved [7:4] NHCM 0: NHCM=0 1: NHCM=1 … 15: NHCM=15 Stream 2-4 4-6 [31:8] … … Table 4: Descriptor for the MCS vector. IRS type defines the use of time- or frequency-domain IRS. Time-domain IRSs typically apply for transmission without FDE at lower optical clock rates. They are also sufficient for transmission. Frequency-domain IRSs enable transmission at higher optical clock rates using FDE and orthogonal transmission and detection of IRSs for multiple streams. If FT=1 (probe frame), optional fields provide a time reference, descriptors for explicit reference sequences (ERS) and the ERS themselves. ERS enable measurement of the direct channel matrix from individual transmitters to individual receivers. The most important role of a probe frame is the beacon sent at the beginning of a superframe. Field Octet Bits Description Time_stamp 3-6 [31:0] Start of probe frame, 10 time resolution ERS_type 7 [7:0] Type of ERS NERS 8 [7:0] Number of ERS ERS n. a. n. a. Block of ERS Table 5 Optional fields for FT=1. stream