 of the terms "master" and "slave" is ONLY in association with the official terminology used in industry specifications and standards, and in no way diminishes Pearson's commitment to promoting diversity, equity, and inclusion, and challenging, countering, and/or combating bias and stereotyping in the global population of the learners we serve. The eNBs working together and cooperating with each other make up what is known as a coordina- tion set. And these scheduling and beamforming decisions are communicated using channel site in- formation (CSI) data shared between the eNBs over the X2 interface. These dynamic coordination techniques require the X2 connectivity between eNBs in the coordination set to be very low latency. Joint processing (JP) is very similar to the CS. However, in joint processing, the user data is avail- able to multiple eNBs, and a scheduling decision determines which eNB should handle transmission to the UE. With joint transmission (JT), multiple eNBs can send data to the edge UE at the same time and using the same frequency. This technique not only reduces interference but improves the received power at the UE and hence the signal quality and data throughput. Because all the eNBs and/or small cells in the coordination set are sending and receiving radio waves to the UE at the same time, then accurate phase/time synchronization is mandatory for any CoMP scenario to work. Table 10-6 summarizes these requirements. Table 10-6 Time Synchronization Requirement for CoMP Application Type of Coordination Phase Accuracy Reference CoMP moderate UL coordinated scheduling < 3 us 3GPP TS 36.104 DL coordinated scheduling 3GPP TS 36.133 CoMP tight DL coordinated beamforming < 3 us 3GPP TS 36.104 DL noncoherent joint transmission 3GPP TS 36.133 UL joint processing UL selection combining UL joint reception 10.3.1 Carrier Aggregation Carrier Aggregation (CA) increases the overall channel bandwidth by aggregating two or more car- riers to transmit data in an aggregated spectrum. CA was introduced in 3GPP Rele