An uplink common physical channel (random access channel) frame structure is disclosed with a separate preamble and data portion. The preamble is used by a base station to detect that a mobile station is attempting a random access request. The data portion of the channel includes user data, and pilot symbols that provide energy for channel estimation during reception of the data portion. A guard interval (TG) is preferably inserted between the preamble and data portion of the frame, which enables data detection to occur during an idle period. As such, the frame structures for both the common physical (random access) uplink channel and dedicated physical (traffic) uplink channel are compatible.

Random access in a mobile telecommunications system

An integrated communication system supporting multiple TDMA or TDD communication protocols, and includes means for selectively communicating according to either protocol. Each protocol defines time frames and/or time slots of a different duration (901, 911), from which is derived a composite time frame (925) having a predefined timing structure. A first base station unit (104) communicates in a first set of time slots of the composite time frame according to a first TDMA or TDD protocol, and a second base station unit (104) (which may be collocated with the first base station unit) communicates in a second set of time slots of the composite time frame according to a second TDMA or TDD protocol. Coordinating electronics (such as a GPS receiver in one or both base station units) are provided so as to prevent collisions between communications occurring between each base station unit and its respective users. In a particular embodiment, a first protocol is GSM protocol, and a second protocol is a TDD protocol utilizing spread spectrum techniques. The TDD protocol is structured so that each time slot is twice the duration of a GSM time slot, and each time frame is four times the duration of a GSM time frame. The system may comprise a number of 'stacked' base stations in a single cell, each operating over a different frequency or using different spreading codes.

Coexisting communication systems

A system and method for optimizing usage of a communications transmission medium. The transmission medium may be sliced into time and frequency domains so as to create time-frequency slices for assignment to users having varying access rates and user-application requirements. Through scheduling of the various speed users within the frequency and time domains, the system and method can efficiently allocate and make use of the available spectrum, thereby accommodating higher rate users requiring greater bandwidths and time slot assignments while still preserving cost-efficient access for lower speed users. Depending on the signal modulation scheme, the time-frequency slices may be allocated on non-contiguous frequency bands. The system and method is also applicable to code-division multiple access (CDMA) techniques by slicing the available code space along time-code domains, frequency-code domains or, in three dimensions, along time-frequency-code domains. Users may be efficiently scheduled based on code space requirements so as to optimize use of the communication medium.

System and method for optimizing spectral efficiency using time-frequency-code slicing

Multi-carrier point-to-multi-point CDMA system implementation reduces hardware changes in legacy single-carrier systems. The number of common downlink channels, such as timing/synchronization and paging channels, is reduced by designating an anchor carrier for transmitting these channels. Procedures for adding carriers and carrier acquisition are simplified through common carrier timing, signaling by the network to the user equipment (UE) of timing offsets and scrambling code selection, and other measures. Channel reuse is employed to minimize changes in asymmetric systems with different numbers of uplink and downlink carriers. Channel Quality Indicator (CQI) field is divided into multiple subfields to enable transmission of multiple CQIs and ACK/NACK indicators on one uplink carrier. Joint and separate scheduling schemes are shown for concurrent scheduling of a data stream transmission to a UE via multiple downlink carriers.

Multi-carrier operation in data transmission systems

A method for operating a cellular communications system of a type that includes a first type of terminal having real-time transmission needs and a second type of terminal having nonreal-time transmission needs. The method includes the steps of (a) determining at periodic intervals a total amount of capacity required to service the first type of terminals; (b) subtracting the determined amount from a current maximum capacity; and (c) allocating all or some of the remaining capacity, if any, to one or more of the second type of terminals.

Load control method and apparatus for CDMA cellular system having circuit and packet switched terminals

The invention relates to a communication method for a digital cellular mobile telephone system and a digital cellular mobile telephone system comprising several base stations and mobiles utilizing time division multiple access. In the system communication is carried out on a predetermined frequency band in a predetermined number of time slots having a predetermined length. In the communication between the mobiles and the base station within the TDMA time slot with the predetermined length, the transmissions to communicate information comprising a few bits or several bits from the mobiles communicating with the same base station at least within the same time slot are mutually substantially orthogonal. Preferably, in order to communicate information, preferably information of the on-off type, such as acknowledgments and channel allocation requests, the mobiles communicating with the same base station use substantially orthogonal transmissions at least to the same base station in the same time slot. Preferably each mobile transmits within the TDMA burst of said TDMA time slot of the predetermined length as a part of the burst a predetermined bit sequence corresponding to the transmitted information bit combination, whereby the predetermined frequency band is unchanged. The bit sequences transmitted by different mobiles to the same base station are mutually substantially orthogonal. By using such substantially orthogonal transmissions it is possible to avoid collisions between the communications of information comprising a few or several bits, typically 1 to 10 bits, such as acknowledgments and channel allocation requests, which typically occur in a time division multiple access system.

Esa Malkamaeki

Papers

A multiple access radio system