The Erlang capacity of multi-service multi-access systems supporting several different radio access technologies was analyzed and compared according to two different operation methods: the separate and common operation methods, by simultaneously considering the link capacity limit per sector as well as channel element (CE) limit in a base station (BS). In a numerical example with GSM-like and WCDMA-like sub-systems, it is shown that we can get up to 60% Erlang capacity improvement through the common operation method using a near optimum so-called service-based user assignment scheme when there is no CE limit in BS. Even with the worst-case assignment scheme, we can still get about 15% capacity improvement over the separate operation method. However, a limited number of CEs in BS reduces the capacity gains of multi-service multi-access systems in both the common operation and separate operation. In order to fully extract the Erlang capacity of multi-service multi-access systems, an efficient method is needed in order to select a proper number of CE in BS while minimizing the equipment cost.

In the adaptive modulation and coding (AMC)-based orthogonal frequency division multiple access (OFDMA) system for broadband wireless service, a large number of users with short packets cause a serious capacity mismatch problem, which incurs resource under-utilization when the data rate of subchannel increases with a better channel condition. To handle the capacity mismatch problem, we propose an AMC-based subchannel multiplexing (ASM) scheme, which allows for sharing the same subchannel among the different simultaneous flows of the same user. Along with the ASM scheme, we also consider multi-class scheduling scheme, which employs the different packet scheduling algorithm for the different service class, e.g., packet loss rate-based (PLR) scheduling algorithm for real-time (RT) service and modified minimum bit rate-based (MMBR) scheduling algorithm for non-real-time (NRT) service. In the typical integrated service scenario with voice, video, and data traffic, we have shown that the proposed schemes significantly improve the overall system capacity.

In this paper, we propose a Distributed Request based CDMA Reservation ALOHA protocol to support multi-class services, such as voice, data, and videophone services, efficiently in multi-rate transmission cellular systems. The proposed protocol introduces a frame structure composed of an access slot and an transmission slot and an adaptive access permission probability based on the estimated number of contending users for each service, in order to control MAI by limiting the access to slots. It can provide voice service without the voice packet dropping probability through the proposed code assignment scheme, unlike other CDMA/PRMA protocols. The code reservation is allowed for voice and videophone services. The low-rate data service basically uses the remaining codes among the codes reserved for the voice service, but it can also use the codes already assigned to voice calls during the their silent periods to utilize codes efficiently. On the other hand, the high-rate data service uses the codes reserved for itself and the remaining codes among the codes reserved for the videophone service. Using the analytic method based on the Markov-chain subsystem model for each service including the handoff calls in uplink cellular systems, we show that the proposed protocol can guarantee the constant GoS for the handoff calls even with a large number of contending users through the proposed code assignment scheme and the access permission probability. Also, we show that the data services are integrated efficiently on the multi-rate transmission environment.